Define a file descriptor reservation/commit/rollback abstraction. #311
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Signed-off-by: Wedson Almeida Filho <[email protected]>
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Review of
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LGTM. |
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The name sounds a bit long, can it just be |
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I think being consistent with the Perhaps |
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On the other hand, if we expect other |
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Let's put the naming discussion in an issue. |
Created #313 to follow up on this. |
Oops, I was doing that in parallel, I will add my comments there :) |
ojeda
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Feb 16, 2024
…_locked The SEV platform device can be shutdown with a null psp_master, e.g., using DEBUG_TEST_DRIVER_REMOVE. Found using KASAN: [ 137.148210] ccp 0000:23:00.1: enabling device (0000 -> 0002) [ 137.162647] ccp 0000:23:00.1: no command queues available [ 137.170598] ccp 0000:23:00.1: sev enabled [ 137.174645] ccp 0000:23:00.1: psp enabled [ 137.178890] general protection fault, probably for non-canonical address 0xdffffc000000001e: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN NOPTI [ 137.182693] KASAN: null-ptr-deref in range [0x00000000000000f0-0x00000000000000f7] [ 137.182693] CPU: 93 PID: 1 Comm: swapper/0 Not tainted 6.8.0-rc1+ #311 [ 137.182693] RIP: 0010:__sev_platform_shutdown_locked+0x51/0x180 [ 137.182693] Code: 08 80 3c 08 00 0f 85 0e 01 00 00 48 8b 1d 67 b6 01 08 48 b8 00 00 00 00 00 fc ff df 48 8d bb f0 00 00 00 48 89 f9 48 c1 e9 03 <80> 3c 01 00 0f 85 fe 00 00 00 48 8b 9b f0 00 00 00 48 85 db 74 2c [ 137.182693] RSP: 0018:ffffc900000cf9b0 EFLAGS: 00010216 [ 137.182693] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 000000000000001e [ 137.182693] RDX: 0000000000000000 RSI: 0000000000000008 RDI: 00000000000000f0 [ 137.182693] RBP: ffffc900000cf9c8 R08: 0000000000000000 R09: fffffbfff58f5a66 [ 137.182693] R10: ffffc900000cf9c8 R11: ffffffffac7ad32f R12: ffff8881e5052c28 [ 137.182693] R13: ffff8881e5052c28 R14: ffff8881758e43e8 R15: ffffffffac64abf8 [ 137.182693] FS: 0000000000000000(0000) GS:ffff889de7000000(0000) knlGS:0000000000000000 [ 137.182693] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 137.182693] CR2: 0000000000000000 CR3: 0000001cf7c7e000 CR4: 0000000000350ef0 [ 137.182693] Call Trace: [ 137.182693] <TASK> [ 137.182693] ? show_regs+0x6c/0x80 [ 137.182693] ? __die_body+0x24/0x70 [ 137.182693] ? die_addr+0x4b/0x80 [ 137.182693] ? exc_general_protection+0x126/0x230 [ 137.182693] ? asm_exc_general_protection+0x2b/0x30 [ 137.182693] ? __sev_platform_shutdown_locked+0x51/0x180 [ 137.182693] sev_firmware_shutdown.isra.0+0x1e/0x80 [ 137.182693] sev_dev_destroy+0x49/0x100 [ 137.182693] psp_dev_destroy+0x47/0xb0 [ 137.182693] sp_destroy+0xbb/0x240 [ 137.182693] sp_pci_remove+0x45/0x60 [ 137.182693] pci_device_remove+0xaa/0x1d0 [ 137.182693] device_remove+0xc7/0x170 [ 137.182693] really_probe+0x374/0xbe0 [ 137.182693] ? srso_return_thunk+0x5/0x5f [ 137.182693] __driver_probe_device+0x199/0x460 [ 137.182693] driver_probe_device+0x4e/0xd0 [ 137.182693] __driver_attach+0x191/0x3d0 [ 137.182693] ? __pfx___driver_attach+0x10/0x10 [ 137.182693] bus_for_each_dev+0x100/0x190 [ 137.182693] ? __pfx_bus_for_each_dev+0x10/0x10 [ 137.182693] ? __kasan_check_read+0x15/0x20 [ 137.182693] ? srso_return_thunk+0x5/0x5f [ 137.182693] ? _raw_spin_unlock+0x27/0x50 [ 137.182693] driver_attach+0x41/0x60 [ 137.182693] bus_add_driver+0x2a8/0x580 [ 137.182693] driver_register+0x141/0x480 [ 137.182693] __pci_register_driver+0x1d6/0x2a0 [ 137.182693] ? srso_return_thunk+0x5/0x5f [ 137.182693] ? esrt_sysfs_init+0x1cd/0x5d0 [ 137.182693] ? __pfx_sp_mod_init+0x10/0x10 [ 137.182693] sp_pci_init+0x22/0x30 [ 137.182693] sp_mod_init+0x14/0x30 [ 137.182693] ? __pfx_sp_mod_init+0x10/0x10 [ 137.182693] do_one_initcall+0xd1/0x470 [ 137.182693] ? __pfx_do_one_initcall+0x10/0x10 [ 137.182693] ? parameq+0x80/0xf0 [ 137.182693] ? srso_return_thunk+0x5/0x5f [ 137.182693] ? __kmalloc+0x3b0/0x4e0 [ 137.182693] ? kernel_init_freeable+0x92d/0x1050 [ 137.182693] ? kasan_populate_vmalloc_pte+0x171/0x190 [ 137.182693] ? srso_return_thunk+0x5/0x5f [ 137.182693] kernel_init_freeable+0xa64/0x1050 [ 137.182693] ? __pfx_kernel_init+0x10/0x10 [ 137.182693] kernel_init+0x24/0x160 [ 137.182693] ? __switch_to_asm+0x3e/0x70 [ 137.182693] ret_from_fork+0x40/0x80 [ 137.182693] ? __pfx_kernel_init+0x10/0x10 [ 137.182693] ret_from_fork_asm+0x1b/0x30 [ 137.182693] </TASK> [ 137.182693] Modules linked in: [ 137.538483] ---[ end trace 0000000000000000 ]--- Fixes: 1b05ece ("crypto: ccp - During shutdown, check SEV data pointer before using") Cc: [email protected] Reviewed-by: Mario Limonciello <[email protected]> Signed-off-by: Kim Phillips <[email protected]> Reviewed-by: Liam Merwick <[email protected]> Acked-by: John Allen <[email protected]> Signed-off-by: Herbert Xu <[email protected]>
Ayush1325
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Apr 22, 2025
Dave Hansen reports the following crash on a 32-bit system with CONFIG_HIGHMEM=y and CONFIG_X86_PAE=y: > 0xf75fe000 is the mem_map[] entry for the first page >4GB. It > obviously wasn't allocated, thus the oops. BUG: unable to handle page fault for address: f75fe000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page *pdpt = 0000000002da2001 *pde = 000000000300c067 *pte = 0000000000000000 Oops: Oops: 0002 [Rust-for-Linux#1] SMP NOPTI CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.15.0-rc1-00288-ge618ee89561b-dirty Rust-for-Linux#311 PREEMPT(undef) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 EIP: __free_pages_core+0x3c/0x74 ... Call Trace: memblock_free_pages+0x11/0x2c memblock_free_all+0x2ce/0x3a0 mm_core_init+0xf5/0x320 start_kernel+0x296/0x79c i386_start_kernel+0xad/0xb0 startup_32_smp+0x151/0x154 The mem_map[] is allocated up to the end of ZONE_HIGHMEM which is defined by max_pfn. The bug was introduced by this recent commit: 6faea34 ("arch, mm: streamline HIGHMEM freeing") Previously, freeing of high memory was also clamped to the end of ZONE_HIGHMEM but after this change, memblock_free_all() tries to free memory above the of ZONE_HIGHMEM as well and that causes access to mem_map[] entries beyond the end of the memory map. To fix this, discard the memory after max_pfn from memblock on 32-bit systems so that core MM would be aware only of actually usable memory. [ mingo: Fixed build failure. ] Fixes: 6faea34 ("arch, mm: streamline HIGHMEM freeing") Reported-by: Dave Hansen <[email protected]> Tested-by: Arnd Bergmann <[email protected]> Tested-by: Dave Hansen <[email protected]> Signed-off-by: Mike Rapoport (Microsoft) <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Acked-by: Dave Hansen <[email protected]> Cc: Andy Shevchenko <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Davide Ciminaghi <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Sean Christopherson <[email protected]> Cc: [email protected] Link: https://lore.kernel.org/r/[email protected]
ojeda
pushed a commit
that referenced
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Apr 29, 2025
Dave Hansen reports the following crash on a 32-bit system with CONFIG_HIGHMEM=y and CONFIG_X86_PAE=y: > 0xf75fe000 is the mem_map[] entry for the first page >4GB. It > obviously wasn't allocated, thus the oops. BUG: unable to handle page fault for address: f75fe000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page *pdpt = 0000000002da2001 *pde = 000000000300c067 *pte = 0000000000000000 Oops: Oops: 0002 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 0 Comm: swapper Not tainted 6.15.0-rc1-00288-ge618ee89561b-dirty #311 PREEMPT(undef) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 EIP: __free_pages_core+0x3c/0x74 ... Call Trace: memblock_free_pages+0x11/0x2c memblock_free_all+0x2ce/0x3a0 mm_core_init+0xf5/0x320 start_kernel+0x296/0x79c i386_start_kernel+0xad/0xb0 startup_32_smp+0x151/0x154 The mem_map[] is allocated up to the end of ZONE_HIGHMEM which is defined by max_pfn. The bug was introduced by this recent commit: 6faea34 ("arch, mm: streamline HIGHMEM freeing") Previously, freeing of high memory was also clamped to the end of ZONE_HIGHMEM but after this change, memblock_free_all() tries to free memory above the of ZONE_HIGHMEM as well and that causes access to mem_map[] entries beyond the end of the memory map. To fix this, discard the memory after max_pfn from memblock on 32-bit systems so that core MM would be aware only of actually usable memory. Fixes: 6faea34 ("arch, mm: streamline HIGHMEM freeing") Reported-by: Dave Hansen <[email protected]> Tested-by: Arnd Bergmann <[email protected]> Signed-off-by: Mike Rapoport (Microsoft) <[email protected]> Signed-off-by: Ingo Molnar <[email protected]> Cc: Andy Shevchenko <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Davide Ciminaghi <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Matthew Wilcox <[email protected]> Cc: Paolo Bonzini <[email protected]> Cc: Sean Christopherson <[email protected]> Cc: [email protected] Link: https://lore.kernel.org/r/[email protected] # discussion and submission
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Once we have a
File, we can create a file descriptor (fd) for it with this abstraction. I use it in Binder to transfer file descriptor between processes.Signed-off-by: Wedson Almeida Filho [email protected]