[19/27] SCSI: scsi_lib: fix potential NULL dereference
From: Greg KH <gregkh@suse.de>
Date: 2011-12-07 17:04:05
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2.6.32-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Jiri Slaby <redacted> commit 03b147083a2f9a2a3fbbd2505fa88ffa3c6ab194 upstream. Stanse found a potential NULL dereference in scsi_kill_request. Instead of triggering BUG() in 'if (unlikely(cmd == NULL))' branch, the kernel will Oops earlier on cmd dereference. Move the dereferences after the if. Signed-off-by: Jiri Slaby <redacted> Signed-off-by: James Bottomley <redacted> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- drivers/scsi/scsi_lib.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c@@ -1370,9 +1370,9 @@ static int scsi_lld_busy(struct request_ static void scsi_kill_request(struct request *req, struct request_queue *q) { struct scsi_cmnd *cmd = req->special; - struct scsi_device *sdev = cmd->device; - struct scsi_target *starget = scsi_target(sdev); - struct Scsi_Host *shost = sdev->host; + struct scsi_device *sdev; + struct scsi_target *starget; + struct Scsi_Host *shost; blk_start_request(req);
@@ -1382,6 +1382,9 @@ static void scsi_kill_request(struct req BUG(); } + sdev = cmd->device; + starget = scsi_target(sdev); + shost = sdev->host; scsi_init_cmd_errh(cmd); cmd->result = DID_NO_CONNECT << 16; atomic_inc(&cmd->device->iorequest_cnt);