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dscho
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entry_count is used in update_one() for two purposes: 1. to skip through the number of processed entries in in-memory index 2. to record the number of entries this cache-tree covers on disk Unfortunately when CE_REMOVE is present these numbers are not the same because CE_REMOVE entries are automatically removed before writing to disk but entry_count is not adjusted and still counts CE_REMOVE entries. Separate the two use cases into two different variables. #1 is taken care by the new field count in struct cache_tree_sub and entry_count is prepared for #2. Signed-off-by: Nguyễn Thái Ngọc Duy <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
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The DWIM mode of checkout allows you to run "git checkout foo" when there is no existing local ref or path called "foo", and there is exactly _one_ remote with a remote-tracking branch called "foo". Git will automatically create a new local branch called "foo" using the remote-tracking "foo" as its starting point and configured upstream. For example, consider the following unconventional (but perfectly valid) remote setup: [remote "origin"] fetch = refs/heads/*:refs/remotes/origin/* [remote "frotz"] fetch = refs/heads/*:refs/remotes/frotz/nitfol/* Case 1: Assume both "origin" and "frotz" have remote-tracking branches called "foo", at "refs/remotes/origin/foo" and "refs/remotes/frotz/nitfol/foo" respectively. In this case "git checkout foo" should fail, because there is more than one remote with a "foo" branch. Case 2: Assume only "frotz" have a remote-tracking branch called "foo". In this case "git checkout foo" should succeed, and create a local branch "foo" from "refs/remotes/frotz/nitfol/foo", using remote branch "foo" from "frotz" as its upstream. The current code hardcodes the assumption that all remote-tracking branches must match the "refs/remotes/$remote/*" pattern (which is true for remotes with "conventional" refspecs, but not true for the "frotz" remote above). When running "git checkout foo", the current code looks for exactly one ref matching "refs/remotes/*/foo", hence in the above example, it fails to find "refs/remotes/frotz/nitfol/foo", which causes it to fail both case #1 and #2. The better way to handle the above example is to actually study the fetch refspecs to deduce the candidate remote-tracking branches for "foo"; i.e. assume "foo" is a remote branch being fetched, and then map "refs/heads/foo" through the refspecs in order to get the corresponding remote-tracking branches "refs/remotes/origin/foo" and "refs/remotes/frotz/nitfol/foo". Finally we check which of these happens to exist in the local repo, and if there is exactly one, we have an unambiguous match for "git checkout foo", and may proceed. This fixes most of the failing tests introduced in the previous patch. Signed-off-by: Johan Herland <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
dscho
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We have two ways of dealing with empty pathspec: 1. limit it to current prefix 2. match the entire working directory Some commands go with #1, some #2. get_pathspec() and parse_pathspec() only support #1. Make parse_pathspec() reject empty pathspec by default. #1 and #2 can be specified via new flags. This makes it more expressive about default behavior at command level. Signed-off-by: Nguyễn Thái Ngọc Duy <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
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In 41c21f2 (branch.c: Validate tracking branches with refspecs instead of refs/remotes/*), we changed the rules for what is considered a valid tracking branch (a.k.a. upstream branch). We now use the configured remotes and their refspecs to determine whether a proposed tracking branch is in fact within the domain of a remote, and we then use that information to deduce the upstream configuration (branch.<name>.remote and branch.<name>.merge). However, with that change, we also check that - in addition to a matching refspec - the result of mapping the tracking branch through that refspec (i.e. the corresponding ref name in the remote repo) happens to start with "refs/heads/". In other words, we require that a tracking branch refers to a _branch_ in the remote repo. Now, consider that you are e.g. setting up an automated building/testing infrastructure for a group of similar "source" repositories. The build/test infrastructure consists of a central scheduler, and a number of build/test "slave" machines that perform the actual build/test work. The scheduler monitors the group of similar repos for changes (e.g. with a periodic "git fetch"), and triggers builds/tests to be run on one or more slaves. Graphically the changes flow between the repos like this: Source #1 -------v ----> Slave #1 / Source #2 -----> Scheduler -----> Slave #2 \ Source #3 -------^ ----> Slave #3 ... ... The scheduler maintains a single Git repo with each of the source repos set up as distinct remotes. The slaves also need access to all the changes from all of the source repos, so they pull from the scheduler repo, but using the following custom refspec: remote.origin.fetch = "+refs/remotes/*:refs/remotes/*" This makes all of the scheduler's remote-tracking branches automatically available as identical remote-tracking branches in each of the slaves. Now, consider what happens if a slave tries to create a local branch with one of the remote-tracking branches as upstream: git branch local_branch --track refs/remotes/source-1/some_branch Git now looks at the configured remotes (in this case there is only "origin", pointing to the scheduler's repo) and sees refs/remotes/source-1/some_branch matching origin's refspec. Mapping through that refspec we find that the corresponding remote ref name is "refs/remotes/source-1/some_branch". However, since this remote ref name does not start with "refs/heads/", we discard it as a suitable upstream, and the whole command fails. This patch adds a testcase demonstrating this failure by creating two source repos ("a" and "b") that are forwarded through a scheduler ("c") to a slave repo ("d"), that then tries create a local branch with an upstream. See the next patch in this series for the exciting conclusion to this story... Reported-by: Per Cederqvist <[email protected]> Signed-off-by: Johan Herland <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
dscho
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Sep 10, 2014
The main loop in strbuf_utf8_replace() could summed up as:
while ('src' is still valid) {
1) advance 'src' to copy ANSI escape sequences
2) advance 'src' to copy/replace visible characters
}
The problem is after #1, 'src' may have reached the end of the string
(so 'src' points to NUL) and #2 will continue to copy that NUL as if
it's a normal character. Because the output is stored in a strbuf,
this NUL accounted in the 'len' field as well. Check after #1 and
break the loop if necessary.
The test does not look obvious, but the combination of %>>() should
make a call trace like this
show_log()
pretty_print_commit()
format_commit_message()
strbuf_expand()
format_commit_item()
format_and_pad_commit()
strbuf_utf8_replace()
where %C(auto)%d would insert a color reset escape sequence in the end
of the string given to strbuf_utf8_replace() and show_log() uses
fwrite() to send everything to stdout (including the incorrect NUL
inserted by strbuf_utf8_replace)
Signed-off-by: Nguyễn Thái Ngọc Duy <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
dscho
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Jan 18, 2015
Don't chop test_expect_success line into pieces and concatenate with '\'. That's so 2005. Signed-off-by: Junio C Hamano <[email protected]>
dscho
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dscho
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Signed-off-by: Junio C Hamano <[email protected]>
dscho
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The collect_parents() function now is responsible for
1. parsing the commits given on the command line into a list of
commits to be merged;
2. filtering these parents into independent ones; and
3. optionally calling fmt_merge_msg() via prepare_merge_message()
to prepare an auto-generated merge log message, using fake
contents that FETCH_HEAD would have had if these commits were
fetched from the current repository with "git pull . $args..."
Make "git merge FETCH_HEAD" to be the same as the traditional
git merge "$(git fmt-merge-msg <.git/FETCH_HEAD)" $commits
invocation of the command in "git pull", where $commits are the ones
that appear in FETCH_HEAD that are not marked as not-for-merge, by
making it do a bit more, specifically:
- noticing "FETCH_HEAD" is the only "commit" on the command line
and picking the commits that are not marked as not-for-merge as
the list of commits to be merged (substitute for step #1 above);
- letting the resulting list fed to step #2 above;
- doing the step #3 above, using the contents of the FETCH_HEAD
instead of fake contents crafted from the list of commits parsed
in the step #1 above.
Note that this changes the semantics. "git merge FETCH_HEAD" has
always behaved as if the first commit in the FETCH_HEAD file were
directly specified on the command line, creating a two-way merge
whose auto-generated merge log said "merge commit xyz". With this
change, if the previous fetch was to grab multiple branches (e.g.
"git fetch $there topic-a topic-b"), the new world order is to
create an octopus, behaving as if "git pull $there topic-a topic-b"
were run. This is a deliberate change to make that happen, and
can be seen in the changes to t3033 tests.
Signed-off-by: Junio C Hamano <[email protected]>
dscho
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Oct 30, 2023
When "update-index --unresolve $path" cannot find the resolve-undo record for the path the user requested to unresolve, it stuffs the blobs from HEAD and MERGE_HEAD to stage #2 and stage #3 as a fallback. For this reason, the operation does not even start unless both "HEAD" and "MERGE_HEAD" exist. This is suboptimal in a few ways: * It does not recreate stage #1. Even though it is a correct design decision not to do so (because it is impossible to recreate in general cases, without knowing how we got there, including what merge strategy was used), it is much less useful not to have that information in the index. * It limits the "unresolve" operation only during a conflicted "git merge" and nothing else. Other operations like "rebase", "cherry-pick", and "switch -m" may result in conflicts, and the user may want to unresolve the conflict that they incorrectly resolved in order to redo the resolution, but the fallback would not kick in. * Most importantly, the entire "unresolve" operation is disabled after a conflicted merge is committed and MERGE_HEAD is removed, even though the index has perfectly usable resolve-undo records. By lazily reading the HEAD and MERGE_HEAD only when we need to go to the fallback codepath, we will allow cases where resolve-undo records are available (which is 100% of the time, unless the user is reading from an index file created by Git more than 10 years ago) to proceed even after a conflicted merge was committed, during other mergy operations that do not use MERGE_HEAD, or after the result of such mergy operations has been committed. Signed-off-by: Junio C Hamano <[email protected]>
dscho
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Jan 24, 2024
It is tempting to think of "files and directories" of the current directory as valid inputs to the add and set subcommands of git sparse-checkout. However, in non-cone mode, they often aren't and using them as potential completions leads to *many* forms of confusion: Issue #1. It provides the *wrong* files and directories. For git sparse-checkout add we always want to add files and directories not currently in our sparse checkout, which means we want file and directories not currently present in the current working tree. Providing the files and directories currently present is thus always wrong. For git sparse-checkout set we have a similar problem except in the subset of cases where we are trying to narrow our checkout to a strict subset of what we already have. That is not a very common scenario, especially since it often does not even happen to be true for the first use of the command; for years we required users to create a sparse-checkout via git sparse-checkout init git sparse-checkout set <args...> (or use a clone option that did the init step for you at clone time). The init command creates a minimal sparse-checkout with just the top-level directory present, meaning the set command has to be used to expand the checkout. Thus, only in a special and perhaps unusual cases would any of the suggestions from normal file and directory completion be appropriate. Issue #2: Suggesting patterns that lead to warnings is unfriendly. If the user specifies any regular file and omits the leading '/', then the sparse-checkout command will warn the user that their command is problematic and suggest they use a leading slash instead. Issue #3: Completion gets confused by leading '/', and provides wrong paths. Users often want to anchor their patterns to the toplevel of the repository, especially when listing individual files. There are a number of reasons for this, but notably even sparse-checkout encourages them to do so (as noted above). However, if users do so (via adding a leading '/' to their pattern), then bash completion will interpret the leading slash not as a request for a path at the toplevel of the repository, but as a request for a path at the root of the filesytem. That means at best that completion cannot help with such paths, and if it does find any completions, they are almost guaranteed to be wrong. Issue #4: Suggesting invalid patterns from subdirectories is unfriendly. There is no per-directory equivalent to .gitignore with sparse-checkouts. There is only a single worktree-global $GIT_DIR/info/sparse-checkout file. As such, paths to files must be specified relative to the toplevel of a repository. Providing suggestions of paths that are relative to the current working directory, as bash completion defaults to, is wrong when the current working directory is not the worktree toplevel directory. Issue #5: Paths with special characters will be interpreted incorrectly The entries in the sparse-checkout file are patterns, not paths. While most paths also qualify as patterns (though even in such cases it would be better for users to not use them directly but prefix them with a leading '/'), there are a variety of special characters that would need special escaping beyond the normal shell escaping: '*', '?', '\', '[', ']', and any leading '#' or '!'. If completion suggests any such paths, users will likely expect them to be treated as an exact path rather than as a pattern that might match some number of files other than 1. However, despite the first four issues, we can note that _if_ users are using tab completion, then they are probably trying to specify a path in the index. As such, we transform their argument into a top-level-rooted pattern that matches such a file. For example, if they type: git sparse-checkout add Make<TAB> we could "complete" to git sparse-checkout add /Makefile or, if they ran from the Documentation/technical/ subdirectory: git sparse-checkout add m<TAB> we could "complete" it to: git sparse-checkout add /Documentation/technical/multi-pack-index.txt Note in both cases I use "complete" in quotes, because we actually add characters both before and after the argument in question, so we are kind of abusing "bash completions" to be "bash completions AND beginnings". The fifth issue is a bit stickier, especially when you consider that we not only need to deal with escaping issues because of special meanings of patterns in sparse-checkout & gitignore files, but also that we need to consider escaping issues due to ls-files needing to sometimes quote or escape characters, and because the shell needs to escape some characters. The multiple interacting forms of escaping could get ugly; this patch makes no attempt to do so and simply documents that we decided to not deal with those corner cases for now but at least get the common cases right. Signed-off-by: Elijah Newren <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
dscho
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Recent versions of the gcc and clang Address Sanitizer produce test
failures related to regexec(). This triggers with gcc-10 and clang-8
(but not gcc-9 nor clang-7). Running:
make CC=gcc-10 SANITIZE=address test
results in failures in t4018, t3206, and t4062.
The cause seems to be that when built with ASan, we use a different
version of regexec() than normal. And this version doesn't understand
the REG_STARTEND flag. Here's my evidence supporting that.
The failure in t4062 is an ASan warning:
expecting success of 4062.2 '-G matches':
git diff --name-only -G "^(0{64}){64}$" HEAD^ >out &&
test 4096-zeroes.txt = "$(cat out)"
=================================================================
==672994==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7fa76f672000 at pc 0x7fa7726f75b6 bp 0x7ffe41bdda70 sp 0x7ffe41bdd220
READ of size 4097 at 0x7fa76f672000 thread T0
#0 0x7fa7726f75b5 (/lib/x86_64-linux-gnu/libasan.so.6+0x4f5b5)
#1 0x562ae0c9c40e in regexec_buf /home/peff/compile/git/git-compat-util.h:1117
#2 0x562ae0c9c40e in diff_grep /home/peff/compile/git/diffcore-pickaxe.c:52
#3 0x562ae0c9cc28 in pickaxe_match /home/peff/compile/git/diffcore-pickaxe.c:166
[...]
In this case we're looking in a buffer which was mmap'd via
reuse_worktree_file(), and whose size is 4096 bytes. But libasan's
regex tries to look at byte 4097 anyway! If we tweak Git like this:
diff --git a/diff.c b/diff.c
index 8e2914c..cfae60c120 100644
--- a/diff.c
+++ b/diff.c
@@ -3880,7 +3880,7 @@ static int reuse_worktree_file(struct index_state *istate,
*/
if (ce_uptodate(ce) ||
(!lstat(name, &st) && !ie_match_stat(istate, ce, &st, 0)))
- return 1;
+ return 0;
return 0;
}
to use a regular buffer (with a trailing NUL) instead of an mmap, then
the complaint goes away.
The other failures are actually diff output with an incorrect funcname
header. If I instrument xdiff to show the funcname matching like so:
diff --git a/xdiff-interface.c b/xdiff-interface.c
index 8509f9e..f6c3dc1986 100644
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -197,6 +197,7 @@ struct ff_regs {
struct ff_reg {
regex_t re;
int negate;
+ char *printable;
} *array;
};
@@ -218,7 +219,12 @@ static long ff_regexp(const char *line, long len,
for (i = 0; i < regs->nr; i++) {
struct ff_reg *reg = regs->array + i;
- if (!regexec_buf(®->re, line, len, 2, pmatch, 0)) {
+ int ret = regexec_buf(®->re, line, len, 2, pmatch, 0);
+ warning("regexec %s:\n regex: %s\n buf: %.*s",
+ ret == 0 ? "matched" : "did not match",
+ reg->printable,
+ (int)len, line);
+ if (!ret) {
if (reg->negate)
return -1;
break;
@@ -264,6 +270,7 @@ void xdiff_set_find_func(xdemitconf_t *xecfg, const char *value, int cflags)
expression = value;
if (regcomp(®->re, expression, cflags))
die("Invalid regexp to look for hunk header: %s", expression);
+ reg->printable = xstrdup(expression);
free(buffer);
value = ep + 1;
}
then when compiling with ASan and gcc-10, running the diff from t4018.66
produces this:
$ git diff -U1 cpp-skip-access-specifiers
warning: regexec did not match:
regex: ^[ ]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*])
buf: private:
warning: regexec matched:
regex: ^((::[[:space:]]*)?[A-Za-z_].*)$
buf: private:
diff --git a/cpp-skip-access-specifiers b/cpp-skip-access-specifiers
index 4d4a9db..ebd6f42 100644
--- a/cpp-skip-access-specifiers
+++ b/cpp-skip-access-specifiers
@@ -6,3 +6,3 @@ private:
void DoSomething();
int ChangeMe;
};
void DoSomething();
- int ChangeMe;
+ int IWasChanged;
};
That first regex should match (and is negated, so it should be telling
us _not_ to match "private:"). But it wouldn't if regexec() is looking
at the whole buffer, and not just the length-limited line we've fed to
regexec_buf(). So this is consistent again with REG_STARTEND being
ignored.
The correct output (compiling without ASan, or gcc-9 with Asan) looks
like this:
warning: regexec matched:
regex: ^[ ]*[A-Za-z_][A-Za-z_0-9]*:[[:space:]]*($|/[/*])
buf: private:
[...more lines that we end up not using...]
warning: regexec matched:
regex: ^((::[[:space:]]*)?[A-Za-z_].*)$
buf: class RIGHT : public Baseclass
diff --git a/cpp-skip-access-specifiers b/cpp-skip-access-specifiers
index 4d4a9db..ebd6f42 100644
--- a/cpp-skip-access-specifiers
+++ b/cpp-skip-access-specifiers
@@ -6,3 +6,3 @@ class RIGHT : public Baseclass
void DoSomething();
- int ChangeMe;
+ int IWasChanged;
};
So it really does seem like libasan's regex engine is ignoring
REG_STARTEND. We should be able to work around it by compiling with
NO_REGEX, which would use our local regexec(). But to make matters even
more interesting, this isn't enough by itself.
Because ASan has support from the compiler, it doesn't seem to intercept
our call to regexec() at the dynamic library level. It actually
recognizes when we are compiling a call to regexec() and replaces it
with ASan-specific code at that point. And unlike most of our other
compat code, where we might have git_mmap() or similar, the actual
symbol name in the compiled compat/regex code is regexec(). So just
compiling with NO_REGEX isn't enough; we still end up in libasan!
We can work around that by having the preprocessor replace regexec with
git_regexec (both in the callers and in the actual implementation), and
we truly end up with a call to our custom regex code, even when
compiling with ASan. That's probably a good thing to do anyway, as it
means anybody looking at the symbols later (e.g., in a debugger) would
have a better indication of which function is which. So we'll do the
same for the other common regex functions (even though just regexec() is
enough to fix this ASan problem).
Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
dscho
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When reusing objects from a pack, we keep track of a set of one or more
`reused_chunk`s, corresponding to sections of one or more object(s) from
a source pack that we are reusing. Each chunk contains two pieces of
information:
- the offset of the first object in the source pack (relative to the
beginning of the source pack)
- the difference between that offset, and the corresponding offset in
the pack we're generating
The purpose of keeping track of these is so that we can patch an
OFS_DELTAs that cross over a section of the reuse pack that we didn't
take.
For instance, consider a hypothetical pack as shown below:
(chunk #2)
__________...
/
/
+--------+---------+-------------------+---------+
... | <base> | <other> | (unused) | <delta> | ...
+--------+---------+-------------------+---------+
\ /
\______________/
(chunk #1)
Suppose that we are sending objects "base", "other", and "delta", and
that the "delta" object is stored as an OFS_DELTA, and that its base is
"base". If we don't send any objects in the "(unused)" range, we can't
copy the delta'd object directly, since its delta offset includes a
range of the pack that we didn't copy, so we have to account for that
difference when patching and reassembling the delta.
In order to compute this value correctly, we need to know not only where
we are in the packfile we're assembling (with `hashfile_total(f)`) but
also the position of the first byte of the packfile that we are
currently reusing. Currently, this works just fine, since when reusing
only a single pack those two values are always identical (because
verbatim reuse is the first thing pack-objects does when enabled after
writing the pack header).
But when reusing multiple packs which have one or more gaps, we'll need
to account for these two values diverging.
Together, these two allow us to compute the reused chunk's offset
difference relative to the start of the reused pack, as desired.
Helped-by: Jeff King <[email protected]>
Signed-off-by: Taylor Blau <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
dscho
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The t5309 script triggers a racy false positive with SANITIZE=leak on a
multi-core system. Running with "--stress --run=6" usually fails within
10 seconds or so for me, complaining with something like:
+ git index-pack --fix-thin --stdin
fatal: REF_DELTA at offset 46 already resolved (duplicate base 01d7713666f4de822776c7622c10f1b07de280dc?)
=================================================================
==3904583==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 32 byte(s) in 1 object(s) allocated from:
#0 0x7fa790d01986 in __interceptor_realloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:98
#1 0x7fa790add769 in __pthread_getattr_np nptl/pthread_getattr_np.c:180
#2 0x7fa790d117c5 in __sanitizer::GetThreadStackTopAndBottom(bool, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:150
#3 0x7fa790d11957 in __sanitizer::GetThreadStackAndTls(bool, unsigned long*, unsigned long*, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:598
#4 0x7fa790d03fe8 in __lsan::ThreadStart(unsigned int, unsigned long long, __sanitizer::ThreadType) ../../../../src/libsanitizer/lsan/lsan_posix.cpp:51
#5 0x7fa790d013fd in __lsan_thread_start_func ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:440
#6 0x7fa790adc3eb in start_thread nptl/pthread_create.c:444
#7 0x7fa790b5ca5b in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
SUMMARY: LeakSanitizer: 32 byte(s) leaked in 1 allocation(s).
Aborted
What happens is this:
0. We construct a bogus pack with a duplicate object in it and trigger
index-pack.
1. We spawn a bunch of worker threads to resolve deltas (on my system
it is 16 threads).
2. One of the threads sees the duplicate object and bails by calling
exit(), taking down all of the threads. This is expected and is the
point of the test.
3. At the time exit() is called, we may still be spawning threads from
the main process via pthread_create(). LSan hooks thread creation
to update its book-keeping; it has to know where each thread's
stack is (so it can find entry points for reachable memory). So it
calls pthread_getattr_np() to get information about the new thread.
That may allocate memory that must be freed with a matching call to
pthread_attr_destroy(). Probably LSan does that immediately, but
if you're unlucky enough, the exit() will happen while it's between
those two calls, and the allocated pthread_attr_t appears as a
leak.
This isn't a real leak. It's not even in our code, but rather in the
LSan instrumentation code. So we could just ignore it. But the false
positive can cause people to waste time tracking it down.
It's possibly something that LSan could protect against (e.g., cover the
getattr/destroy pair with a mutex, and then in the final post-exit()
check for leaks try to take the same mutex). But I don't know enough
about LSan to say if that's a reasonable approach or not (or if my
analysis is even completely correct).
In the meantime, it's pretty easy to avoid the race by making creation
of the worker threads "atomic". That is, we'll spawn all of them before
letting any of them start to work. That's easy to do because we already
have a work_lock() mutex for handing out that work. If the main process
takes it, then all of the threads will immediately block until we've
finished spawning and released it.
This shouldn't make any practical difference for non-LSan runs. The
thread spawning is quick, and could happen before any worker thread gets
scheduled anyway.
Probably other spots that use threads are subject to the same issues.
But since we have to manually insert locking (and since this really is
kind of a hack), let's not bother with them unless somebody experiences
a similar racy false-positive in practice.
Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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Includes these pull requests: #1 #6 #10 #11 msysgit#157 msysgit#212 msysgit#260 msysgit#270 Signed-off-by: Derrick Stolee <[email protected]>
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Includes these pull requests: #1 #6 #10 #11 msysgit#157 msysgit#212 msysgit#260 msysgit#270 Signed-off-by: Derrick Stolee <[email protected]>
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Commit d6a8c58 (midx-write.c: support reading an existing MIDX with `packs_to_include`, 2024-05-29) changed the MIDX generation machinery to support reading from an existing MIDX when writing a new one. Unfortunately, the rest of the MIDX generation machinery is not prepared to deal with such a change. For instance, the function responsible for adding to the object ID fanout table from a MIDX source (midx_fanout_add_midx_fanout()) will gladly add objects from an existing MIDX for some fanout level regardless of whether or not those objects came from packs that are to be included in the subsequent MIDX write. This results in broken pseudo-pack object order (leading to incorrect object traversal results) and segmentation faults, like so (generated by running the added test prior to the changes in midx-write.c): #0 0x000055ee31393f47 in midx_pack_order (ctx=0x7ffdde205c70) at midx-write.c:590 #1 0x000055ee31395a69 in write_midx_internal (object_dir=0x55ee32570440 ".git/objects", packs_to_include=0x7ffdde205e20, packs_to_drop=0x0, preferred_pack_name=0x0, refs_snapshot=0x0, flags=15) at midx-write.c:1171 #2 0x000055ee31395f38 in write_midx_file_only (object_dir=0x55ee32570440 ".git/objects", packs_to_include=0x7ffdde205e20, preferred_pack_name=0x0, refs_snapshot=0x0, flags=15) at midx-write.c:1274 [...] In stack frame #0, the code on midx-write.c:590 is using the new pack ID corresponding to some object which was added from the existing MIDX. Importantly, the pack from which that object was selected in the existing MIDX does not appear in the new MIDX as it was excluded via `--stdin-packs`. In this instance, the pack in question had pack ID "1" in the existing MIDX, but since it was excluded from the new MIDX, we never filled in that entry in the pack_perm table, resulting in: (gdb) p *ctx->pack_perm@2 $1 = {0, 1515870810} Which is what causes the segfault above when we try and read: struct pack_info *pack = &ctx->info[ctx->pack_perm[i]]; if (pack->bitmap_pos == BITMAP_POS_UNKNOWN) pack->bitmap_pos = 0; Fundamentally, we should be able to read information from an existing MIDX when generating a new one. But in practice the midx-write.c code assumes that we won't run into issues like the above with incongruent pack IDs, and often makes those assumptions in extremely subtle and fragile ways. Instead, let's avoid reading from an existing MIDX altogether, and stick with the pre-d6a8c58675 implementation. Harden against any regressions in this area by adding a test which demonstrates these issues. Signed-off-by: Taylor Blau <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
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When performing multi-pack reuse, reuse_partial_packfile_from_bitmap() is responsible for generating an array of bitmapped_pack structs from which to perform reuse. In the multi-pack case, we loop over the MIDXs packs and copy the result of calling `nth_bitmapped_pack()` to construct the list of reusable paths. But we may also want to do pack-reuse over a single pack, either because we only had one pack to perform reuse over (in the case of single-pack bitmaps), or because we explicitly asked to do single pack reuse even with a MIDX[^1]. When this is the case, the array we generate of reusable packs contains only a single element, which is either (a) the pack attached to the single-pack bitmap, or (b) the MIDX's preferred pack. In 795006f (pack-bitmap: gracefully handle missing BTMP chunks, 2024-04-15), we refactored the reuse_partial_packfile_from_bitmap() function and stopped assigning the pack_int_id field when reusing only the MIDX's preferred pack. This results in an uninitialized read down in try_partial_reuse() like so: ==7474==WARNING: MemorySanitizer: use-of-uninitialized-value #0 0x55c5cd191dde in try_partial_reuse pack-bitmap.c:1887:8 #1 0x55c5cd191dde in reuse_partial_packfile_from_bitmap_1 pack-bitmap.c:2001:8 #2 0x55c5cd191dde in reuse_partial_packfile_from_bitmap pack-bitmap.c:2105:3 #3 0x55c5cce0bd0e in get_object_list_from_bitmap builtin/pack-objects.c:4043:3 #4 0x55c5cce0bd0e in get_object_list builtin/pack-objects.c:4156:27 #5 0x55c5cce0bd0e in cmd_pack_objects builtin/pack-objects.c:4596:3 #6 0x55c5ccc8fac8 in run_builtin git.c:474:11 which happens when try_partial_reuse() tries to call midx_pair_to_pack_pos() when it tries to reject cross-pack deltas. Avoid the uninitialized read by ensuring that the pack_int_id field is set in the single-pack reuse case by setting it to either the MIDX preferred pack's pack_int_id, or '-1', in the case of single-pack bitmaps. In the latter case, we never read the pack_int_id field, so the choice of '-1' is intentional as a "garbage in, garbage out" measure. Guard against further regressions in this area by adding a test which ensures that we do not throw out deltas from the preferred pack as "cross-pack" due to an uninitialized pack_int_id. [^1]: This can happen for a couple of reasons, either because the repository is configured with 'pack.allowPackReuse=(true|single)', or because the MIDX was generated prior to the introduction of the BTMP chunk, which contains information necessary to perform multi-pack reuse. Reported-by: Kyle Lippincott <[email protected]> Signed-off-by: Taylor Blau <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
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Memory sanitizer (msan) is detecting a use of an uninitialized variable
(`size`) in `read_attr_from_index`:
==2268==WARNING: MemorySanitizer: use-of-uninitialized-value
#0 0x5651f3416504 in read_attr_from_index git/attr.c:868:11
#1 0x5651f3415530 in read_attr git/attr.c
#2 0x5651f3413d74 in bootstrap_attr_stack git/attr.c:968:6
#3 0x5651f3413d74 in prepare_attr_stack git/attr.c:1004:2
#4 0x5651f3413d74 in collect_some_attrs git/attr.c:1199:2
#5 0x5651f3413144 in git_check_attr git/attr.c:1345:2
#6 0x5651f34728da in convert_attrs git/convert.c:1320:2
#7 0x5651f3473425 in would_convert_to_git_filter_fd git/convert.c:1373:2
#8 0x5651f357a35e in index_fd git/object-file.c:2630:34
#9 0x5651f357aa15 in index_path git/object-file.c:2657:7
#10 0x5651f35db9d9 in add_to_index git/read-cache.c:766:7
#11 0x5651f35dc170 in add_file_to_index git/read-cache.c:799:9
#12 0x5651f321f9b2 in add_files git/builtin/add.c:346:7
#13 0x5651f321f9b2 in cmd_add git/builtin/add.c:565:18
#14 0x5651f321d327 in run_builtin git/git.c:474:11
#15 0x5651f321bc9e in handle_builtin git/git.c:729:3
#16 0x5651f321a792 in run_argv git/git.c:793:4
#17 0x5651f321a792 in cmd_main git/git.c:928:19
#18 0x5651f33dde1f in main git/common-main.c:62:11
The issue exists because `size` is an output parameter from
`read_blob_data_from_index`, but it's only modified if
`read_blob_data_from_index` returns non-NULL. The read of `size` when
calling `read_attr_from_buf` unconditionally may read from an
uninitialized value. `read_attr_from_buf` checks that `buf` is non-NULL
before reading from `size`, but by then it's already too late: the
uninitialized read will have happened already. Furthermore, there's no
guarantee that the compiler won't reorder things so that it checks
`size` before checking `!buf`.
Make the call to `read_attr_from_buf` conditional on `buf` being
non-NULL, ensuring that `size` is not read if it's never set.
Signed-off-by: Kyle Lippincott <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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Signed-off-by: Junio C Hamano <[email protected]>
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When using `--fixed-value` with a key whose value is left empty (implied
as being "true"), 'git config' may crash when invoked like either of:
$ git config set --file=config --value=value --fixed-value \
section.key pattern
$ git config --file=config --fixed-value section.key value pattern
The original bugreport[1] bisects to 00bbdde (builtin/config:
introduce "set" subcommand, 2024-05-06), which is a red-herring, since
the original bugreport uses the new 'git config set' invocation.
The behavior likely bisects back to c90702a (config: plumb
--fixed-value into config API, 2020-11-25), which introduces the new
--fixed-value option in the first place.
Looking at the relevant frame from a failed process's coredump, the
crash appears in config.c::matches() like so:
(gdb) up
#1 0x000055b3e8b06022 in matches (key=0x55b3ea894360 "section.key", value=0x0,
store=0x7ffe99076eb0) at config.c:2884
2884 return !strcmp(store->fixed_value, value);
where we are trying to compare the `--fixed-value` argument to `value`,
which is NULL.
Avoid attempting to match `--fixed-value` for configuration keys with no
explicit value. A future patch could consider the empty value to mean
"true", "yes", "on", etc. when invoked with `--type=bool`, but let's
punt on that for now in the name of avoiding the segfault.
[1]: https://lore.kernel.org/git/CANrWfmTek1xErBLrnoyhHN+gWU+rw14y6SQ+abZyzGoaBjmiKA@mail.gmail.com/
Reported-by: Han Jiang <[email protected]>
Signed-off-by: Taylor Blau <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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It was recently reported that concurrent reads and writes may cause the
reftable backend to segfault. The root cause of this is that we do not
properly keep track of reftable readers across reloads.
Suppose that you have a reftable iterator and then decide to reload the
stack while iterating through the iterator. When the stack has been
rewritten since we have created the iterator, then we would end up
discarding a subset of readers that may still be in use by the iterator.
The consequence is that we now try to reference deallocated memory,
which of course segfaults.
One way to trigger this is in t5616, where some background maintenance
jobs have been leaking from one test into another. This leads to stack
traces like the following one:
+ git -c protocol.version=0 -C pc1 fetch --filter=blob:limit=29999 --refetch origin
AddressSanitizer:DEADLYSIGNAL
=================================================================
==657994==ERROR: AddressSanitizer: SEGV on unknown address 0x7fa0f0ec6089 (pc 0x55f23e52ddf9 bp
0x7ffe7bfa1700 sp 0x7ffe7bfa1700 T0)
==657994==The signal is caused by a READ memory access.
#0 0x55f23e52ddf9 in get_var_int reftable/record.c:29
#1 0x55f23e53295e in reftable_decode_keylen reftable/record.c:170
#2 0x55f23e532cc0 in reftable_decode_key reftable/record.c:194
#3 0x55f23e54e72e in block_iter_next reftable/block.c:398
#4 0x55f23e5573dc in table_iter_next_in_block reftable/reader.c:240
#5 0x55f23e5573dc in table_iter_next reftable/reader.c:355
#6 0x55f23e5573dc in table_iter_next reftable/reader.c:339
#7 0x55f23e551283 in merged_iter_advance_subiter reftable/merged.c:69
#8 0x55f23e55169e in merged_iter_next_entry reftable/merged.c:123
#9 0x55f23e55169e in merged_iter_next_void reftable/merged.c:172
#10 0x55f23e537625 in reftable_iterator_next_ref reftable/generic.c:175
#11 0x55f23e2cf9c6 in reftable_ref_iterator_advance refs/reftable-backend.c:464
#12 0x55f23e2d996e in ref_iterator_advance refs/iterator.c:13
#13 0x55f23e2d996e in do_for_each_ref_iterator refs/iterator.c:452
#14 0x55f23dca6767 in get_ref_map builtin/fetch.c:623
#15 0x55f23dca6767 in do_fetch builtin/fetch.c:1659
#16 0x55f23dca6767 in fetch_one builtin/fetch.c:2133
#17 0x55f23dca6767 in cmd_fetch builtin/fetch.c:2432
#18 0x55f23dba7764 in run_builtin git.c:484
#19 0x55f23dba7764 in handle_builtin git.c:741
#20 0x55f23dbab61e in run_argv git.c:805
#21 0x55f23dbab61e in cmd_main git.c:1000
#22 0x55f23dba4781 in main common-main.c:64
#23 0x7fa0f063fc89 in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58
#24 0x7fa0f063fd44 in __libc_start_main_impl ../csu/libc-start.c:360
#25 0x55f23dba6ad0 in _start (git+0xadfad0) (BuildId: 803b2b7f59beb03d7849fb8294a8e2145dd4aa27)
While it is somewhat awkward that the maintenance processes survive
tests in the first place, it is totally expected that reftables should
work alright with concurrent writers. Seemingly they don't.
The only underlying resource that we need to care about in this context
is the reftable reader, which is responsible for reading a single table
from disk. These readers get discarded immediately (unless reused) when
calling `reftable_stack_reload()`, which is wrong. We can only close
them once we know that there are no iterators using them anymore.
Prepare for a fix by converting the reftable readers to be refcounted.
Reported-by: Jeff King <[email protected]>
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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An internal customer reported a segfault when running `git sparse-checkout set` with the `index.sparse` config enabled. I was unable to reproduce it locally, but with their help we debugged into the failing process and discovered the following stacktrace: ``` #0 0x00007ff6318fb7b0 in rehash (map=0x3dfb00d0440, newsize=1048576) at hashmap.c:125 #1 0x00007ff6318fbc66 in hashmap_add (map=0x3dfb00d0440, entry=0x3dfb5c58bc8) at hashmap.c:247 #2 0x00007ff631937a70 in hash_index_entry (istate=0x3dfb00d0400, ce=0x3dfb5c58bc8) at name-hash.c:122 #3 0x00007ff631938a2f in add_name_hash (istate=0x3dfb00d0400, ce=0x3dfb5c58bc8) at name-hash.c:638 #4 0x00007ff631a064de in set_index_entry (istate=0x3dfb00d0400, nr=8291, ce=0x3dfb5c58bc8) at sparse-index.c:255 #5 0x00007ff631a06692 in add_path_to_index (oid=0x5ff130, base=0x5ff580, path=0x3dfb4b725da "<redacted>", mode=33188, context=0x5ff570) at sparse-index.c:307 #6 0x00007ff631a3b48c in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41f60, base=0x5ff580, depth=2, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:46 #7 0x00007ff631a3b60b in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41e80, base=0x5ff580, depth=1, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:80 #8 0x00007ff631a3b60b in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41ac8, base=0x5ff580, depth=0, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:80 #9 0x00007ff631a06a95 in expand_index (istate=0x3dfb00d0100, pl=0x0) at sparse-index.c:422 #10 0x00007ff631a06cbd in ensure_full_index (istate=0x3dfb00d0100) at sparse-index.c:456 #11 0x00007ff631990d08 in index_name_stage_pos (istate=0x3dfb00d0100, name=0x3dfb0020080 "algorithm/levenshtein", namelen=21, stage=0, search_mode=EXPAND_SPARSE) at read-cache.c:556 #12 0x00007ff631990d6c in index_name_pos (istate=0x3dfb00d0100, name=0x3dfb0020080 "algorithm/levenshtein", namelen=21) at read-cache.c:566 #13 0x00007ff63180dbb5 in sanitize_paths (argc=185, argv=0x3dfb0030018, prefix=0x0, skip_checks=0) at builtin/sparse-checkout.c:756 #14 0x00007ff63180de50 in sparse_checkout_set (argc=185, argv=0x3dfb0030018, prefix=0x0) at builtin/sparse-checkout.c:860 #15 0x00007ff63180e6c5 in cmd_sparse_checkout (argc=186, argv=0x3dfb0030018, prefix=0x0) at builtin/sparse-checkout.c:1063 #16 0x00007ff6317234cb in run_builtin (p=0x7ff631ad9b38 <commands+2808>, argc=187, argv=0x3dfb0030018) at git.c:548 #17 0x00007ff6317239c0 in handle_builtin (argc=187, argv=0x3dfb0030018) at git.c:808 #18 0x00007ff631723c7d in run_argv (argcp=0x5ffdd0, argv=0x5ffd78) at git.c:877 #19 0x00007ff6317241d1 in cmd_main (argc=187, argv=0x3dfb0030018) at git.c:1017 #20 0x00007ff631838b60 in main (argc=190, argv=0x3dfb0030000) at common-main.c:64 ``` The very bottom of the stack being the `rehash()` method from `hashmap.c` as called within the `name-hash` API made me look at where these hashmaps were being used in the sparse index logic. These were being copied across indexes, which seems dangerous. Indeed, clearing these hashmaps and setting them as not initialized fixes the segfault. The second commit is a response to a test failure that happens in `t1092-sparse-checkout-compatibility.sh` where `git stash pop` starts to fail because the underlying `git checkout-index` process fails due to colliding files. Passing the `-f` flag appears to work, but it's unclear why this name-hash change causes that change in behavior.
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This one is a little bit more curious. In t6112, we have a test that
exercises the `git rev-list --filter` option with invalid filters. We
execute git-rev-list(1) via `test_must_fail`, which means that we check
for leaks even though Git exits with an error code. This causes the
following leak:
Direct leak of 27 byte(s) in 1 object(s) allocated from:
#0 0x5555555e6946 in realloc.part.0 lsan_interceptors.cpp.o
#1 0x5555558fb4b6 in xrealloc wrapper.c:137:8
#2 0x5555558b6e06 in strbuf_grow strbuf.c:112:2
#3 0x5555558b7550 in strbuf_add strbuf.c:311:2
#4 0x5555557c1a88 in strbuf_addstr strbuf.h:310:2
#5 0x5555557c1d4c in parse_list_objects_filter list-objects-filter-options.c:261:3
#6 0x555555885ead in handle_revision_pseudo_opt revision.c:2899:3
#7 0x555555884e20 in setup_revisions revision.c:3014:11
#8 0x5555556c4b42 in cmd_rev_list builtin/rev-list.c:588:9
#9 0x5555555ec5e3 in run_builtin git.c:483:11
#10 0x5555555eb1e4 in handle_builtin git.c:749:13
#11 0x5555555ec001 in run_argv git.c:819:4
#12 0x5555555eaf94 in cmd_main git.c:954:19
#13 0x5555556fd569 in main common-main.c:64:11
#14 0x7ffff7ca714d in __libc_start_call_main (.../lib/libc.so.6+0x2a14d)
#15 0x7ffff7ca7208 in __libc_start_main@GLIBC_2.2.5 (.../libc.so.6+0x2a208)
#16 0x5555555ad064 in _start (git+0x59064)
This leak is valid, as we call `die()` and do not clean up the memory at
all. But what's curious is that this is the only leak reported, because
we don't clean up any other allocated memory, either, and I have no idea
why the leak sanitizer treats this buffer specially.
In any case, we can work around the leak by shuffling things around a
bit. Instead of calling `gently_parse_list_objects_filter()` and dying
after we have modified the filter spec, we simply do so beforehand. Like
this we don't allocate the buffer in the error case, which makes the
reported leak go away.
It's not pretty, but it manages to make t6112 leak free.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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When running t5601 with the leak checker enabled we can see a hang in
our CI systems. This hang seems to be system-specific, as I cannot
reproduce it on my own machine.
As it turns out, the issue is in those testcases that exercise cloning
of `~repo`-style paths. All of the testcases that hang eventually end up
interpreting "repo" as the username and will call getpwnam(3p) with that
username. That should of course be fine, and getpwnam(3p) should just
return an error. But instead, the leak sanitizer seems to be recursing
while handling a call to `free()` in the NSS modules:
#0 0x00007ffff7fd98d5 in _dl_update_slotinfo (req_modid=1, new_gen=2) at ../elf/dl-tls.c:720
#1 0x00007ffff7fd9ac4 in update_get_addr (ti=0x7ffff7a91d80, gen=<optimized out>) at ../elf/dl-tls.c:916
#2 0x00007ffff7fdc85c in __tls_get_addr () at ../sysdeps/x86_64/tls_get_addr.S:55
#3 0x00007ffff7a27e04 in __lsan::GetAllocatorCache () at ../../../../src/libsanitizer/lsan/lsan_linux.cpp:27
#4 0x00007ffff7a2b33a in __lsan::Deallocate (p=0x0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:127
#5 __lsan::lsan_free (p=0x0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:220
...
#261505 0x00007ffff7fd99f2 in free (ptr=<optimized out>) at ../include/rtld-malloc.h:50
#261506 _dl_update_slotinfo (req_modid=1, new_gen=2) at ../elf/dl-tls.c:822
#261507 0x00007ffff7fd9ac4 in update_get_addr (ti=0x7ffff7a91d80, gen=<optimized out>) at ../elf/dl-tls.c:916
#261508 0x00007ffff7fdc85c in __tls_get_addr () at ../sysdeps/x86_64/tls_get_addr.S:55
#261509 0x00007ffff7a27e04 in __lsan::GetAllocatorCache () at ../../../../src/libsanitizer/lsan/lsan_linux.cpp:27
#261510 0x00007ffff7a2b33a in __lsan::Deallocate (p=0x5020000001e0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:127
#261511 __lsan::lsan_free (p=0x5020000001e0) at ../../../../src/libsanitizer/lsan/lsan_allocator.cpp:220
#261512 0x00007ffff793da25 in module_load (module=0x515000000280) at ./nss/nss_module.c:188
#261513 0x00007ffff793dee5 in __nss_module_load (module=0x515000000280) at ./nss/nss_module.c:302
#261514 __nss_module_get_function (module=0x515000000280, name=name@entry=0x7ffff79b9128 "getpwnam_r") at ./nss/nss_module.c:328
#261515 0x00007ffff793e741 in __GI___nss_lookup_function (fct_name=<optimized out>, ni=<optimized out>) at ./nss/nsswitch.c:137
#261516 __GI___nss_next2 (ni=ni@entry=0x7fffffffa458, fct_name=fct_name@entry=0x7ffff79b9128 "getpwnam_r", fct2_name=fct2_name@entry=0x0, fctp=fctp@entry=0x7fffffffa460,
status=status@entry=0, all_values=all_values@entry=0) at ./nss/nsswitch.c:120
#261517 0x00007ffff794c6a7 in __getpwnam_r (name=name@entry=0x501000000060 "repo", resbuf=resbuf@entry=0x7ffff79fb320 <resbuf>, buffer=<optimized out>,
buflen=buflen@entry=1024, result=result@entry=0x7fffffffa4b0) at ../nss/getXXbyYY_r.c:343
#261518 0x00007ffff794c4d8 in getpwnam (name=0x501000000060 "repo") at ../nss/getXXbyYY.c:140
#261519 0x00005555557e37ff in getpw_str (username=0x5020000001a1 "repo", len=4) at path.c:613
#261520 0x00005555557e3937 in interpolate_path (path=0x5020000001a0 "~repo", real_home=0) at path.c:654
#261521 0x00005555557e3aea in enter_repo (path=0x501000000040 "~repo", strict=0) at path.c:718
#261522 0x000055555568f0ba in cmd_upload_pack (argc=1, argv=0x502000000100, prefix=0x0, repo=0x0) at builtin/upload-pack.c:57
#261523 0x0000555555575ba8 in run_builtin (p=0x555555a20c98 <commands+3192>, argc=2, argv=0x502000000100, repo=0x555555a53b20 <the_repo>) at git.c:481
#261524 0x0000555555576067 in handle_builtin (args=0x7fffffffaab0) at git.c:742
#261525 0x000055555557678d in cmd_main (argc=2, argv=0x7fffffffac58) at git.c:912
#261526 0x00005555556963cd in main (argc=2, argv=0x7fffffffac58) at common-main.c:64
Note that this stack is more than 260000 function calls deep. Run under
the debugger this will eventually segfault, but in our CI systems it
seems like this just hangs forever.
I assume that this is a bug either in the leak sanitizer or in glibc, as
I cannot reproduce it on my machine. In any case, let's work around the
bug for now by marking those tests with the "!SANITIZE_LEAK" prereq.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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There's a race with LSan when spawning threads and one of the threads
calls die(). We worked around one such problem with index-pack in the
previous commit, but it exists in git-grep, too. You can see it with:
make SANITIZE=leak THREAD_BARRIER_PTHREAD=YesOnLinux
cd t
./t0003-attributes.sh --stress
which fails pretty quickly with:
==git==4096424==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 32 byte(s) in 1 object(s) allocated from:
#0 0x7f906de14556 in realloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:98
#1 0x7f906dc9d2c1 in __pthread_getattr_np nptl/pthread_getattr_np.c:180
#2 0x7f906de2500d in __sanitizer::GetThreadStackTopAndBottom(bool, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:150
#3 0x7f906de25187 in __sanitizer::GetThreadStackAndTls(bool, unsigned long*, unsigned long*, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:614
#4 0x7f906de17d18 in __lsan::ThreadStart(unsigned int, unsigned long long, __sanitizer::ThreadType) ../../../../src/libsanitizer/lsan/lsan_posix.cpp:53
#5 0x7f906de143a9 in ThreadStartFunc<false> ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:431
#6 0x7f906dc9bf51 in start_thread nptl/pthread_create.c:447
#7 0x7f906dd1a677 in __clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:78
As with the previous commit, we can fix this by inserting a barrier that
makes sure all threads have finished their setup before continuing. But
there's one twist in this case: the thread which calls die() is not one
of the worker threads, but the main thread itself!
So we need the main thread to wait in the barrier, too, until all
threads have gotten to it. And thus we initialize the barrier for
num_threads+1, to account for all of the worker threads plus the main
one.
If we then test as above, t0003 should run indefinitely.
Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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In 1b9e9be (csum-file.c: use unsafe SHA-1 implementation when available, 2024-09-26) we have converted our `struct hashfile` to use the unsafe SHA1 backend, which results in a significant speedup. One needs to be careful with how to use that structure now though because callers need to consistently use either the safe or unsafe variants of SHA1, as otherwise one can easily trigger corruption. As it turns out, we have one inconsistent usage in our tree because we directly initialize `struct hashfile_checkpoint::ctx` with the safe variant of SHA1, but end up writing to that context with the unsafe ones. This went unnoticed so far because our CI systems do not exercise different hash functions for these two backends, and consequently safe and unsafe variants are equivalent. But when using SHA1DC as safe and OpenSSL as unsafe backend this leads to a crash an t1050: ++ git -c core.compression=0 add large1 AddressSanitizer:DEADLYSIGNAL ================================================================= ==1367==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000040 (pc 0x7ffff7a01a99 bp 0x507000000db0 sp 0x7fffffff5690 T0) ==1367==The signal is caused by a READ memory access. ==1367==Hint: address points to the zero page. #0 0x7ffff7a01a99 in EVP_MD_CTX_copy_ex (/nix/store/h1ydpxkw9qhjdxjpic1pdc2nirggyy6f-openssl-3.3.2/lib/libcrypto.so.3+0x201a99) (BuildId: 41746a580d39075fc85e8c8065b6c07fb34e97d4) #1 0x555555ddde56 in openssl_SHA1_Clone ../sha1/openssl.h:40:2 #2 0x555555dce2fc in git_hash_sha1_clone_unsafe ../object-file.c:123:2 #3 0x555555c2d5f8 in hashfile_checkpoint ../csum-file.c:211:2 #4 0x555555b9905d in deflate_blob_to_pack ../bulk-checkin.c:286:4 #5 0x555555b98ae9 in index_blob_bulk_checkin ../bulk-checkin.c:362:15 #6 0x555555ddab62 in index_blob_stream ../object-file.c:2756:9 #7 0x555555dda420 in index_fd ../object-file.c:2778:9 #8 0x555555ddad76 in index_path ../object-file.c:2796:7 #9 0x555555e947f3 in add_to_index ../read-cache.c:771:7 #10 0x555555e954a4 in add_file_to_index ../read-cache.c:804:9 #11 0x5555558b5c39 in add_files ../builtin/add.c:355:7 #12 0x5555558b412e in cmd_add ../builtin/add.c:578:18 #13 0x555555b1f493 in run_builtin ../git.c:480:11 #14 0x555555b1bfef in handle_builtin ../git.c:740:9 #15 0x555555b1e6f4 in run_argv ../git.c:807:4 #16 0x555555b1b87a in cmd_main ../git.c:947:19 #17 0x5555561649e6 in main ../common-main.c:64:11 #18 0x7ffff742a1fb in __libc_start_call_main (/nix/store/65h17wjrrlsj2rj540igylrx7fqcd6vq-glibc-2.40-36/lib/libc.so.6+0x2a1fb) (BuildId: bf320110569c8ec2425e9a0c5e4eb7e97f1fb6e4) #19 0x7ffff742a2b8 in __libc_start_main@GLIBC_2.2.5 (/nix/store/65h17wjrrlsj2rj540igylrx7fqcd6vq-glibc-2.40-36/lib/libc.so.6+0x2a2b8) (BuildId: bf320110569c8ec2425e9a0c5e4eb7e97f1fb6e4) #20 0x555555772c84 in _start (git+0x21ec84) ==1367==Register values: rax = 0x0000511000001080 rbx = 0x0000000000000000 rcx = 0x000000000000000c rdx = 0x0000000000000000 rdi = 0x0000000000000000 rsi = 0x0000507000000db0 rbp = 0x0000507000000db0 rsp = 0x00007fffffff5690 r8 = 0x0000000000000000 r9 = 0x0000000000000000 r10 = 0x0000000000000000 r11 = 0x00007ffff7a01a30 r12 = 0x0000000000000000 r13 = 0x00007fffffff6b38 r14 = 0x00007ffff7ffd000 r15 = 0x00005555563b9910 AddressSanitizer can not provide additional info. SUMMARY: AddressSanitizer: SEGV (/nix/store/h1ydpxkw9qhjdxjpic1pdc2nirggyy6f-openssl-3.3.2/lib/libcrypto.so.3+0x201a99) (BuildId: 41746a580d39075fc85e8c8065b6c07fb34e97d4) in EVP_MD_CTX_copy_ex ==1367==ABORTING ./test-lib.sh: line 1023: 1367 Aborted git $config add large1 error: last command exited with $?=134 not ok 4 - add with -c core.compression=0 Fix the issue by using the unsafe variant instead. Signed-off-by: Patrick Steinhardt <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
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Same as with the preceding commit, git-fast-import(1) is using the safe
variant to initialize a hashfile checkpoint. This leads to a segfault
when passing the checkpoint into the hashfile subsystem because it would
use the unsafe variants instead:
++ git --git-dir=R/.git fast-import --big-file-threshold=1
AddressSanitizer:DEADLYSIGNAL
=================================================================
==577126==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000040 (pc 0x7ffff7a01a99 bp 0x5070000009c0 sp 0x7fffffff5b30 T0)
==577126==The signal is caused by a READ memory access.
==577126==Hint: address points to the zero page.
#0 0x7ffff7a01a99 in EVP_MD_CTX_copy_ex (/nix/store/h1ydpxkw9qhjdxjpic1pdc2nirggyy6f-openssl-3.3.2/lib/libcrypto.so.3+0x201a99) (BuildId: 41746a580d39075fc85e8c8065b6c07fb34e97d4)
#1 0x555555ddde56 in openssl_SHA1_Clone ../sha1/openssl.h:40:2
#2 0x555555dce2fc in git_hash_sha1_clone_unsafe ../object-file.c:123:2
#3 0x555555c2d5f8 in hashfile_checkpoint ../csum-file.c:211:2
#4 0x5555559647d1 in stream_blob ../builtin/fast-import.c:1110:2
#5 0x55555596247b in parse_and_store_blob ../builtin/fast-import.c:2031:3
#6 0x555555967f91 in file_change_m ../builtin/fast-import.c:2408:5
#7 0x55555595d8a2 in parse_new_commit ../builtin/fast-import.c:2768:4
#8 0x55555595bb7a in cmd_fast_import ../builtin/fast-import.c:3614:4
#9 0x555555b1f493 in run_builtin ../git.c:480:11
#10 0x555555b1bfef in handle_builtin ../git.c:740:9
#11 0x555555b1e6f4 in run_argv ../git.c:807:4
#12 0x555555b1b87a in cmd_main ../git.c:947:19
#13 0x5555561649e6 in main ../common-main.c:64:11
#14 0x7ffff742a1fb in __libc_start_call_main (/nix/store/65h17wjrrlsj2rj540igylrx7fqcd6vq-glibc-2.40-36/lib/libc.so.6+0x2a1fb) (BuildId: bf320110569c8ec2425e9a0c5e4eb7e97f1fb6e4)
#15 0x7ffff742a2b8 in __libc_start_main@GLIBC_2.2.5 (/nix/store/65h17wjrrlsj2rj540igylrx7fqcd6vq-glibc-2.40-36/lib/libc.so.6+0x2a2b8) (BuildId: bf320110569c8ec2425e9a0c5e4eb7e97f1fb6e4)
#16 0x555555772c84 in _start (git+0x21ec84)
==577126==Register values:
rax = 0x0000511000000cc0 rbx = 0x0000000000000000 rcx = 0x000000000000000c rdx = 0x0000000000000000
rdi = 0x0000000000000000 rsi = 0x00005070000009c0 rbp = 0x00005070000009c0 rsp = 0x00007fffffff5b30
r8 = 0x0000000000000000 r9 = 0x0000000000000000 r10 = 0x0000000000000000 r11 = 0x00007ffff7a01a30
r12 = 0x0000000000000000 r13 = 0x00007fffffff6b60 r14 = 0x00007ffff7ffd000 r15 = 0x00005555563b9910
AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/nix/store/h1ydpxkw9qhjdxjpic1pdc2nirggyy6f-openssl-3.3.2/lib/libcrypto.so.3+0x201a99) (BuildId: 41746a580d39075fc85e8c8065b6c07fb34e97d4) in EVP_MD_CTX_copy_ex
==577126==ABORTING
./test-lib.sh: line 1039: 577126 Aborted git --git-dir=R/.git fast-import --big-file-threshold=1 < input
error: last command exited with $?=134
not ok 167 - R: blob bigger than threshold
The segfault is only exposed in case the unsafe and safe backends are
different from one another.
Fix the issue by initializing the context with the unsafe SHA1 variant.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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Our CI jobs sometimes see false positive leaks like this:
=================================================================
==3904583==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 32 byte(s) in 1 object(s) allocated from:
#0 0x7fa790d01986 in __interceptor_realloc ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:98
#1 0x7fa790add769 in __pthread_getattr_np nptl/pthread_getattr_np.c:180
#2 0x7fa790d117c5 in __sanitizer::GetThreadStackTopAndBottom(bool, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:150
#3 0x7fa790d11957 in __sanitizer::GetThreadStackAndTls(bool, unsigned long*, unsigned long*, unsigned long*, unsigned long*) ../../../../src/libsanitizer/sanitizer_common/sanitizer_linux_libcdep.cpp:598
#4 0x7fa790d03fe8 in __lsan::ThreadStart(unsigned int, unsigned long long, __sanitizer::ThreadType) ../../../../src/libsanitizer/lsan/lsan_posix.cpp:51
#5 0x7fa790d013fd in __lsan_thread_start_func ../../../../src/libsanitizer/lsan/lsan_interceptors.cpp:440
#6 0x7fa790adc3eb in start_thread nptl/pthread_create.c:444
#7 0x7fa790b5ca5b in clone3 ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
This is not a leak in our code, but appears to be a race between one
thread calling exit() while another one is in LSan's stack setup code.
You can reproduce it easily by running t0003 or t5309 with --stress
(these trigger it because of the threading in git-grep and index-pack
respectively).
This may be a bug in LSan, but regardless of whether it is eventually
fixed, it is useful to work around it so that we stop seeing these false
positives.
We can recognize it by the mention of the sanitizer functions in the
DEDUP_TOKEN line. With this patch, the scripts mentioned above should
run with --stress indefinitely.
Signed-off-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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Includes these pull requests: #1 #6 #10 #11 msysgit#157 msysgit#212 msysgit#260 msysgit#270 Signed-off-by: Derrick Stolee <[email protected]>
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An internal customer reported a segfault when running `git sparse-checkout set` with the `index.sparse` config enabled. I was unable to reproduce it locally, but with their help we debugged into the failing process and discovered the following stacktrace: ``` #0 0x00007ff6318fb7b0 in rehash (map=0x3dfb00d0440, newsize=1048576) at hashmap.c:125 #1 0x00007ff6318fbc66 in hashmap_add (map=0x3dfb00d0440, entry=0x3dfb5c58bc8) at hashmap.c:247 #2 0x00007ff631937a70 in hash_index_entry (istate=0x3dfb00d0400, ce=0x3dfb5c58bc8) at name-hash.c:122 #3 0x00007ff631938a2f in add_name_hash (istate=0x3dfb00d0400, ce=0x3dfb5c58bc8) at name-hash.c:638 #4 0x00007ff631a064de in set_index_entry (istate=0x3dfb00d0400, nr=8291, ce=0x3dfb5c58bc8) at sparse-index.c:255 #5 0x00007ff631a06692 in add_path_to_index (oid=0x5ff130, base=0x5ff580, path=0x3dfb4b725da "<redacted>", mode=33188, context=0x5ff570) at sparse-index.c:307 #6 0x00007ff631a3b48c in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41f60, base=0x5ff580, depth=2, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:46 #7 0x00007ff631a3b60b in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41e80, base=0x5ff580, depth=1, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:80 #8 0x00007ff631a3b60b in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41ac8, base=0x5ff580, depth=0, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:80 #9 0x00007ff631a06a95 in expand_index (istate=0x3dfb00d0100, pl=0x0) at sparse-index.c:422 #10 0x00007ff631a06cbd in ensure_full_index (istate=0x3dfb00d0100) at sparse-index.c:456 #11 0x00007ff631990d08 in index_name_stage_pos (istate=0x3dfb00d0100, name=0x3dfb0020080 "algorithm/levenshtein", namelen=21, stage=0, search_mode=EXPAND_SPARSE) at read-cache.c:556 #12 0x00007ff631990d6c in index_name_pos (istate=0x3dfb00d0100, name=0x3dfb0020080 "algorithm/levenshtein", namelen=21) at read-cache.c:566 #13 0x00007ff63180dbb5 in sanitize_paths (argc=185, argv=0x3dfb0030018, prefix=0x0, skip_checks=0) at builtin/sparse-checkout.c:756 #14 0x00007ff63180de50 in sparse_checkout_set (argc=185, argv=0x3dfb0030018, prefix=0x0) at builtin/sparse-checkout.c:860 #15 0x00007ff63180e6c5 in cmd_sparse_checkout (argc=186, argv=0x3dfb0030018, prefix=0x0) at builtin/sparse-checkout.c:1063 #16 0x00007ff6317234cb in run_builtin (p=0x7ff631ad9b38 <commands+2808>, argc=187, argv=0x3dfb0030018) at git.c:548 #17 0x00007ff6317239c0 in handle_builtin (argc=187, argv=0x3dfb0030018) at git.c:808 #18 0x00007ff631723c7d in run_argv (argcp=0x5ffdd0, argv=0x5ffd78) at git.c:877 #19 0x00007ff6317241d1 in cmd_main (argc=187, argv=0x3dfb0030018) at git.c:1017 #20 0x00007ff631838b60 in main (argc=190, argv=0x3dfb0030000) at common-main.c:64 ``` The very bottom of the stack being the `rehash()` method from `hashmap.c` as called within the `name-hash` API made me look at where these hashmaps were being used in the sparse index logic. These were being copied across indexes, which seems dangerous. Indeed, clearing these hashmaps and setting them as not initialized fixes the segfault. The second commit is a response to a test failure that happens in `t1092-sparse-checkout-compatibility.sh` where `git stash pop` starts to fail because the underlying `git checkout-index` process fails due to colliding files. Passing the `-f` flag appears to work, but it's unclear why this name-hash change causes that change in behavior.
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When trying to create a Unix socket in a path that exceeds the maximum
socket name length we try to first change the directory into the parent
folder before creating the socket to reduce the length of the name. When
this fails we error out of `unix_sockaddr_init()` with an error code,
which indicates to the caller that the context has not been initialized.
Consequently, they don't release that context.
This leads to a memory leak: when we have already populated the context
with the original directory that we need to chdir(3p) back into, but
then the chdir(3p) into the socket's parent directory fails, then we
won't release the original directory's path. The leak is exposed by
t0301, but only when running tests in a directory hierarchy whose path
is long enough to make the socket name length exceed the maximum socket
name length:
Direct leak of 129 byte(s) in 1 object(s) allocated from:
#0 0x5555555e85c6 in realloc.part.0 lsan_interceptors.cpp.o
#1 0x55555590e3d6 in xrealloc ../wrapper.c:140:8
#2 0x5555558c8fc6 in strbuf_grow ../strbuf.c:114:2
#3 0x5555558cacab in strbuf_getcwd ../strbuf.c:605:3
#4 0x555555923ff6 in unix_sockaddr_init ../unix-socket.c:65:7
#5 0x555555923e42 in unix_stream_connect ../unix-socket.c:84:6
#6 0x55555562a984 in send_request ../builtin/credential-cache.c:46:11
#7 0x55555562a89e in do_cache ../builtin/credential-cache.c:108:6
#8 0x55555562a655 in cmd_credential_cache ../builtin/credential-cache.c:178:3
#9 0x555555700547 in run_builtin ../git.c:480:11
#10 0x5555556ff0e0 in handle_builtin ../git.c:740:9
#11 0x5555556ffee8 in run_argv ../git.c:807:4
#12 0x5555556fee6b in cmd_main ../git.c:947:19
#13 0x55555593f689 in main ../common-main.c:64:11
#14 0x7ffff7a2a1fb in __libc_start_call_main (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a1fb) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#15 0x7ffff7a2a2b8 in __libc_start_main@GLIBC_2.2.5 (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a2b8) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#16 0x5555555ad1d4 in _start (git+0x591d4)
DEDUP_TOKEN: ___interceptor_realloc.part.0--xrealloc--strbuf_grow--strbuf_getcwd--unix_sockaddr_init--unix_stream_connect--send_request--do_cache--cmd_credential_cache--run_builtin--handle_builtin--run_argv--cmd_main--main--__libc_start_call_main--__libc_start_main@GLIBC_2.2.5--_start
SUMMARY: LeakSanitizer: 129 byte(s) leaked in 1 allocation(s).
Fix this leak.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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We don't free the result of `remote_default_branch()`, leading to a
memory leak. This leak is exposed by t9211, but only when run with Meson
with the `-Db_sanitize=leak` option:
Direct leak of 5 byte(s) in 1 object(s) allocated from:
#0 0x5555555cfb93 in malloc (scalar+0x7bb93)
#1 0x5555556b05c2 in do_xmalloc ../wrapper.c:55:8
#2 0x5555556b06c4 in do_xmallocz ../wrapper.c:89:8
#3 0x5555556b0656 in xmallocz ../wrapper.c:97:9
#4 0x5555556b0728 in xmemdupz ../wrapper.c:113:16
#5 0x5555556b07a7 in xstrndup ../wrapper.c:119:9
#6 0x5555555d3a4b in remote_default_branch ../scalar.c:338:14
#7 0x5555555d20e6 in cmd_clone ../scalar.c:493:28
#8 0x5555555d196b in cmd_main ../scalar.c:992:14
#9 0x5555557c4059 in main ../common-main.c:64:11
#10 0x7ffff7a2a1fb in __libc_start_call_main (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a1fb) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#11 0x7ffff7a2a2b8 in __libc_start_main@GLIBC_2.2.5 (/nix/store/h7zcxabfxa7v5xdna45y2hplj31ncf8a-glibc-2.40-36/lib/libc.so.6+0x2a2b8) (BuildId: 0a855678aa0cb573cecbb2bcc73ab8239ec472d0)
#12 0x555555592054 in _start (scalar+0x3e054)
DEDUP_TOKEN: __interceptor_malloc--do_xmalloc--do_xmallocz--xmallocz--xmemdupz--xstrndup--remote_default_branch--cmd_clone--cmd_main--main--__libc_start_call_main--__libc_start_main@GLIBC_2.2.5--_start
SUMMARY: LeakSanitizer: 5 byte(s) leaked in 1 allocation(s).
As the `branch` variable may contain a string constant obtained from
parsing command line arguments we cannot free the leaking variable
directly. Instead, introduce a new `branch_to_free` variable that only
ever gets assigned the allocated string and free that one to plug the
leak.
It is unclear why the leak isn't flagged when running the test via our
Makefile.
Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>
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Submodule merges are, in general, similar to other merges based on oid three-way-merge. When a conflict happens, however, Git has two special cases (introduced in 68d03e4) on handling the conflict before yielding it to the user. From the merge-ort and merge-recursive sources: - "Case #1: a is contained in b or vice versa": both strategies try to perform a fast-forward in the submodules if the commit referred by the conflicted submodule is descendant of another; - "Case #2: There are one or more merges that contain a and b in the submodule. If there is only one, then present it as a suggestion to the user, but leave it marked unmerged so the user needs to confirm the resolution." Add a small paragraph on merge-strategies.adoc describing this behavior. Helped-by: Junio C Hamano <[email protected]> Helped-by: Elijah Newren <[email protected]> Signed-off-by: Lucas Seiki Oshiro <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
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Includes these pull requests: #1 #6 #10 #11 msysgit#157 msysgit#212 msysgit#260 msysgit#270 Signed-off-by: Derrick Stolee <[email protected]>
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An internal customer reported a segfault when running `git sparse-checkout set` with the `index.sparse` config enabled. I was unable to reproduce it locally, but with their help we debugged into the failing process and discovered the following stacktrace: ``` #0 0x00007ff6318fb7b0 in rehash (map=0x3dfb00d0440, newsize=1048576) at hashmap.c:125 #1 0x00007ff6318fbc66 in hashmap_add (map=0x3dfb00d0440, entry=0x3dfb5c58bc8) at hashmap.c:247 #2 0x00007ff631937a70 in hash_index_entry (istate=0x3dfb00d0400, ce=0x3dfb5c58bc8) at name-hash.c:122 #3 0x00007ff631938a2f in add_name_hash (istate=0x3dfb00d0400, ce=0x3dfb5c58bc8) at name-hash.c:638 #4 0x00007ff631a064de in set_index_entry (istate=0x3dfb00d0400, nr=8291, ce=0x3dfb5c58bc8) at sparse-index.c:255 #5 0x00007ff631a06692 in add_path_to_index (oid=0x5ff130, base=0x5ff580, path=0x3dfb4b725da "<redacted>", mode=33188, context=0x5ff570) at sparse-index.c:307 #6 0x00007ff631a3b48c in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41f60, base=0x5ff580, depth=2, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:46 #7 0x00007ff631a3b60b in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41e80, base=0x5ff580, depth=1, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:80 #8 0x00007ff631a3b60b in read_tree_at (r=0x7ff631c026a0 <the_repo>, tree=0x3dfb5b41ac8, base=0x5ff580, depth=0, pathspec=0x5ff5a0, fn=0x7ff631a064e5 <add_path_to_index>, context=0x5ff570) at tree.c:80 #9 0x00007ff631a06a95 in expand_index (istate=0x3dfb00d0100, pl=0x0) at sparse-index.c:422 #10 0x00007ff631a06cbd in ensure_full_index (istate=0x3dfb00d0100) at sparse-index.c:456 #11 0x00007ff631990d08 in index_name_stage_pos (istate=0x3dfb00d0100, name=0x3dfb0020080 "algorithm/levenshtein", namelen=21, stage=0, search_mode=EXPAND_SPARSE) at read-cache.c:556 #12 0x00007ff631990d6c in index_name_pos (istate=0x3dfb00d0100, name=0x3dfb0020080 "algorithm/levenshtein", namelen=21) at read-cache.c:566 #13 0x00007ff63180dbb5 in sanitize_paths (argc=185, argv=0x3dfb0030018, prefix=0x0, skip_checks=0) at builtin/sparse-checkout.c:756 #14 0x00007ff63180de50 in sparse_checkout_set (argc=185, argv=0x3dfb0030018, prefix=0x0) at builtin/sparse-checkout.c:860 #15 0x00007ff63180e6c5 in cmd_sparse_checkout (argc=186, argv=0x3dfb0030018, prefix=0x0) at builtin/sparse-checkout.c:1063 #16 0x00007ff6317234cb in run_builtin (p=0x7ff631ad9b38 <commands+2808>, argc=187, argv=0x3dfb0030018) at git.c:548 #17 0x00007ff6317239c0 in handle_builtin (argc=187, argv=0x3dfb0030018) at git.c:808 #18 0x00007ff631723c7d in run_argv (argcp=0x5ffdd0, argv=0x5ffd78) at git.c:877 #19 0x00007ff6317241d1 in cmd_main (argc=187, argv=0x3dfb0030018) at git.c:1017 #20 0x00007ff631838b60 in main (argc=190, argv=0x3dfb0030000) at common-main.c:64 ``` The very bottom of the stack being the `rehash()` method from `hashmap.c` as called within the `name-hash` API made me look at where these hashmaps were being used in the sparse index logic. These were being copied across indexes, which seems dangerous. Indeed, clearing these hashmaps and setting them as not initialized fixes the segfault. The second commit is a response to a test failure that happens in `t1092-sparse-checkout-compatibility.sh` where `git stash pop` starts to fail because the underlying `git checkout-index` process fails due to colliding files. Passing the `-f` flag appears to work, but it's unclear why this name-hash change causes that change in behavior.
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Signed-off-by: Junio C Hamano <[email protected]>
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The GitHub's CI workflow uses 'actions/checkout@v4' to checkout the repository. This action defaults to using the GitHub REST API to obtain the repository if the `git` executable isn't available. The step to build Git in the GitHub workflow can be summarized as: ... - uses: actions/checkout@v4 #1 - run: ci/install-dependencies.sh #2 ... - run: sudo --preserve-env --set-home --user=builder ci/run-build-and-tests.sh #3 ... Step #1, clones the repository, since the `git` executable isn't present at this step, it uses GitHub's REST API to obtain a tar of the repository. Step #2, installs all dependencies, which includes the `git` executable. Step #3, sets up the build, which includes setting up meson in the meson job. At this point the `git` executable is present. This means while the `git` executable is present, the repository doesn't contain the '.git' folder. To keep both the CI's (GitLab and GitHub) behavior consistent and to ensure that the build is performed on a real-world scenario, install `git` before the repository is checked out. This ensures that 'actions/checkout@v4' will clone the repository instead of using a tarball. We also update the package cache while installing `git`, this is because some distros will fail to locate the package without updating the cache. Helped-by: Phillip Wood <[email protected]> Signed-off-by: Karthik Nayak <[email protected]> Signed-off-by: Junio C Hamano <[email protected]>
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