From 222a806af830fda34ad1f6bc991cd226916de060 Mon Sep 17 00:00:00 2001 From: Mark Rustad Date: Thu, 21 Jun 2012 12:23:42 -0700 Subject: [PATCH] [SCSI] Fix NULL dereferences in scsi_cmd_to_driver Avoid crashing if the private_data pointer happens to be NULL. This has been seen sometimes when a host reset happens, notably when there are many LUNs: host3: Assigned Port ID 0c1601 scsi host3: libfc: Host reset succeeded on port (0c1601) BUG: unable to handle kernel NULL pointer dereference at 0000000000000350 IP: [] scsi_send_eh_cmnd+0x58/0x3a0 Process scsi_eh_3 (pid: 4144, threadinfo ffff88030920c000, task ffff880326b160c0) Stack: 000000010372e6ba 0000000000000282 000027100920dca0 ffffffffa0038ee0 0000000000000000 0000000000030003 ffff88030920dc80 ffff88030920dc80 00000002000e0000 0000000a00004000 ffff8803242f7760 ffff88031326ed80 Call Trace: [] ? lock_timer_base+0x70/0x70 [] scsi_eh_tur+0x3e/0xc0 [] scsi_eh_test_devices+0x76/0x170 [] scsi_eh_host_reset+0x85/0x160 [] scsi_eh_ready_devs+0x91/0x110 [] scsi_unjam_host+0xed/0x1f0 [] scsi_error_handler+0x1a8/0x200 [] ? scsi_unjam_host+0x1f0/0x1f0 [] kthread+0x9e/0xb0 [] kernel_thread_helper+0x4/0x10 [] ? kthread_freezable_should_stop+0x70/0x70 [] ? gs_change+0x13/0x13 Code: 25 28 00 00 00 48 89 45 c8 31 c0 48 8b 87 80 00 00 00 48 8d b5 60 ff ff ff 89 d1 48 89 fb 41 89 d6 4c 89 fa 48 8b 80 b8 00 00 00 <48> 8b 80 50 03 00 00 48 8b 00 48 89 85 38 ff ff ff 48 8b 07 4c RIP [] scsi_send_eh_cmnd+0x58/0x3a0 RSP CR2: 0000000000000350 Signed-off-by: Mark Rustad Tested-by: Marcus Dennis Cc: Signed-off-by: James Bottomley --- include/scsi/scsi_cmnd.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h index 1e1198546c72..ac06cc595890 100644 --- a/include/scsi/scsi_cmnd.h +++ b/include/scsi/scsi_cmnd.h @@ -134,10 +134,16 @@ struct scsi_cmnd { static inline struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd) { + struct scsi_driver **sdp; + if (!cmd->request->rq_disk) return NULL; - return *(struct scsi_driver **)cmd->request->rq_disk->private_data; + sdp = (struct scsi_driver **)cmd->request->rq_disk->private_data; + if (!sdp) + return NULL; + + return *sdp; } extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t); -- 2.39.5