From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxim Uvarov Subject: [PATCH] scsi_prep_fn() check for empty queue Date: Wed, 26 Jun 2013 13:02:43 +0400 Message-ID: <1372237363-5156-1-git-send-email-maxim.uvarov@oracle.com> Return-path: Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org Cc: linux-scsi@vger.kernel.org, JBottomley@parallels.com List-Id: linux-scsi@vger.kernel.org This fix: end_request: I/O error, dev sdc, sector 976576 rport-0:0-3: blocked FC remote port time out: removing target and saving binding BUG: unable to handle kernel NULL pointer dereference at 0000000000000400 IP: [] scsi_prep_state_check+0xe/0x99 [] scsi_setup_blk_pc_cmnd+0x1b/0x115 [] scsi_prep_fn+0x29/0x3b [] blk_peek_request+0xe1/0x1b3 [] scsi_request_fn+0x3a/0x4d2 [] __generic_unplug_device+0x32/0x36 [] blk_execute_rq_nowait+0x77/0x9e [] blk_execute_rq+0xa6/0xde [] ? printk+0x41/0x46 [] ? get_rdac_req+0x81/0xe8 [scsi_dh_rdac] [] send_mode_select+0x29f/0x489 [scsi_dh_rdac] [] ? probe_workqueue_execution+0xb1/0xce [] worker_thread+0x1a9/0x237 [] ? send_mode_select+0x0/0x489 [scsi_dh_rdac] [] ? autoremove_wake_function+0x0/0x39 [] ? worker_thread+0x0/0x237 [] kthread+0x7f/0x87 [] child_rip+0xa/0x20 [] ? kthread+0x0/0x87 [] ? child_rip+0x0/0x20 Signed-off-by: Maxim Uvarov --- drivers/scsi/scsi_lib.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 86d5220..8e89ed9 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1295,6 +1295,9 @@ int scsi_prep_fn(struct request_queue *q, struct request *req) struct scsi_device *sdev = q->queuedata; int ret = BLKPREP_KILL; + if (!sdev) + return ret; + if (req->cmd_type == REQ_TYPE_BLOCK_PC) ret = scsi_setup_blk_pc_cmnd(sdev, req); return scsi_prep_return(q, req, ret); -- 1.7.9.5