scsi: qla2xxx: Validate sp before freeing associated memory

System crash with the following signature
[154563.214890] nvme nvme2: NVME-FC{1}: controller connect complete
[154564.169363] qla2xxx [0000:b0:00.1]-3002:2: nvme: Sched: Set ZIO exchange threshold to 3.
[154564.169405] qla2xxx [0000:b0:00.1]-ffffff:2: SET ZIO Activity exchange threshold to 5.
[154565.539974] qla2xxx [0000:b0:00.1]-5013:2: RSCN database changed – 0078 0080 0000.
[154565.545744] qla2xxx [0000:b0:00.1]-5013:2: RSCN database changed – 0078 00a0 0000.
[154565.545857] qla2xxx [0000:b0:00.1]-11a2:2: FEC=enabled (data rate).
[154565.552760] qla2xxx [0000:b0:00.1]-11a2:2: FEC=enabled (data rate).
[154565.553079] BUG: kernel NULL pointer dereference, address: 00000000000000f8
[154565.553080] #PF: supervisor read access in kernel mode
[154565.553082] #PF: error_code(0x0000) - not-present page
[154565.553084] PGD 80000010488ab067 P4D 80000010488ab067 PUD 104978a067 PMD 0
[154565.553089] Oops: 0000 1 PREEMPT SMP PTI
[154565.553092] CPU: 10 PID: 858 Comm: qla2xxx_2_dpc Kdump: loaded Tainted: G           OE     -------  ---  5.14.0-503.11.1.el9_5.x86_64 #1
[154565.553096] Hardware name: HPE Synergy 660 Gen10/Synergy 660 Gen10 Compute Module, BIOS I43 09/30/2024
[154565.553097] RIP: 0010:qla_fab_async_scan.part.0+0x40b/0x870 [qla2xxx]
[154565.553141] Code: 00 00 e8 58 a3 ec d4 49 89 e9 ba 12 20 00 00 4c 89 e6 49 c7 c0 00 ee a8 c0 48 c7 c1 66 c0 a9 c0 bf 00 80 00 10 e8 15 69 00 00 <4c> 8b 8d f8 00 00 00 4d 85 c9 74 35 49 8b 84 24 00 19 00 00 48 8b
[154565.553143] RSP: 0018:ffffb4dbc8aebdd0 EFLAGS: 00010286
[154565.553145] RAX: 0000000000000000 RBX: ffff8ec2cf0908d0 RCX: 0000000000000002
[154565.553147] RDX: 0000000000000000 RSI: ffffffffc0a9c896 RDI: ffffb4dbc8aebd47
[154565.553148] RBP: 0000000000000000 R08: ffffb4dbc8aebd45 R09: 0000000000ffff0a
[154565.553150] R10: 0000000000000000 R11: 000000000000000f R12: ffff8ec2cf0908d0
[154565.553151] R13: ffff8ec2cf090900 R14: 0000000000000102 R15: ffff8ec2cf084000
[154565.553152] FS:  0000000000000000(0000) GS:ffff8ed27f800000(0000) knlGS:0000000000000000
[154565.553154] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[154565.553155] CR2: 00000000000000f8 CR3: 000000113ae0a005 CR4: 00000000007706f0
[154565.553157] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[154565.553158] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[154565.553159] PKRU: 55555554
[154565.553160] Call Trace:
[154565.553162]  <TASK>
[154565.553165]  ? show_trace_log_lvl+0x1c4/0x2df
[154565.553172]  ? show_trace_log_lvl+0x1c4/0x2df
[154565.553177]  ? qla_fab_async_scan.part.0+0x40b/0x870 [qla2xxx]
[154565.553215]  ? __die_body.cold+0x8/0xd
[154565.553218]  ? page_fault_oops+0x134/0x170
[154565.553223]  ? snprintf+0x49/0x70
[154565.553229]  ? exc_page_fault+0x62/0x150
[154565.553238]  ? asm_exc_page_fault+0x22/0x30

Check for sp being non NULL before freeing any associated memory

Fixes: a423994 ("scsi: qla2xxx: Add switch command to simplify fabric discovery")
Cc: [email protected]
Signed-off-by: Anil Gurumurthy <[email protected]>
Signed-off-by: Nilesh Javali <[email protected]>
Reviewed-by: Himanshu Madhani <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Martin K. Petersen <[email protected]>

Author: Anil Gurumurthy

drivers/scsi/qla2xxx/qla_gs.c

@@ -3698,23 +3698,25 @@ int qla_fab_async_scan(scsi_qla_host_t *vha, srb_t *sp)
 	return rval;
 
 done_free_sp:
-	if (sp->u.iocb_cmd.u.ctarg.req) {
-		dma_free_coherent(&vha->hw->pdev->dev,
-		    sp->u.iocb_cmd.u.ctarg.req_allocated_size,
-		    sp->u.iocb_cmd.u.ctarg.req,
-		    sp->u.iocb_cmd.u.ctarg.req_dma);
-		sp->u.iocb_cmd.u.ctarg.req = NULL;
-	}
-	if (sp->u.iocb_cmd.u.ctarg.rsp) {
-		dma_free_coherent(&vha->hw->pdev->dev,
-		    sp->u.iocb_cmd.u.ctarg.rsp_allocated_size,
-		    sp->u.iocb_cmd.u.ctarg.rsp,
-		    sp->u.iocb_cmd.u.ctarg.rsp_dma);
-		sp->u.iocb_cmd.u.ctarg.rsp = NULL;
-	}
+	if (sp) {
+		if (sp->u.iocb_cmd.u.ctarg.req) {
+			dma_free_coherent(&vha->hw->pdev->dev,
+			    sp->u.iocb_cmd.u.ctarg.req_allocated_size,
+			    sp->u.iocb_cmd.u.ctarg.req,
+			    sp->u.iocb_cmd.u.ctarg.req_dma);
+			sp->u.iocb_cmd.u.ctarg.req = NULL;
+		}
+		if (sp->u.iocb_cmd.u.ctarg.rsp) {
+			dma_free_coherent(&vha->hw->pdev->dev,
+			    sp->u.iocb_cmd.u.ctarg.rsp_allocated_size,
+			    sp->u.iocb_cmd.u.ctarg.rsp,
+			    sp->u.iocb_cmd.u.ctarg.rsp_dma);
+			sp->u.iocb_cmd.u.ctarg.rsp = NULL;
+		}
 
-	/* ref: INIT */
-	kref_put(&sp->cmd_kref, qla2x00_sp_release);
+		/* ref: INIT */
+		kref_put(&sp->cmd_kref, qla2x00_sp_release);
+	}
 
 	spin_lock_irqsave(&vha->work_lock, flags);
 	vha->scan.scan_flags &= ~SF_SCANNING;