aboutsummaryrefslogtreecommitdiff
path: root/drivers/ide/au1xxx-ide.c
diff options
context:
space:
mode:
authorAaron Lu <aaron.lu@intel.com>2013-10-10 13:22:36 +0800
committerJames Bottomley <JBottomley@Parallels.com>2013-10-23 14:09:18 +0100
commit10c580e4239df5c3344ca00322eca86ab2de880b (patch)
tree81425dadc373bb8dd7299d81c736e78f3bb87c62 /drivers/ide/au1xxx-ide.c
parent36008cf118235cee49b6753455f33b6f2c3a7543 (diff)
[SCSI] sd: call blk_pm_runtime_init before add_disk
Sujit has found a race condition that would make q->nr_pending unbalanced, it occurs as Sujit explained: " sd_probe_async() -> add_disk() -> disk_add_event() -> schedule(disk_events_workfn) sd_revalidate_disk() blk_pm_runtime_init() return; Let's say the disk_events_workfn() calls sd_check_events() which tries to send test_unit_ready() and because of sd_revalidate_disk() trying to send another commands the test_unit_ready() might be re-queued as the tagged command queuing is disabled. So the race condition is - Thread 1 | Thread 2 sd_revalidate_disk() | sd_check_events() ...nr_pending = 0 as q->dev = NULL| scsi_queue_insert() blk_runtime_pm_init() | blk_pm_requeue_request() -> | nr_pending = -1 since | q->dev != NULL " The problem is, the test_unit_ready request doesn't get counted the first time it is queued, so the later decrement of q->nr_pending in blk_pm_requeue_request makes it unbalanced. Fix this by calling blk_pm_runtime_init before add_disk so that all requests initiated there will all be counted. Signed-off-by: Aaron Lu <aaron.lu@intel.com> Reported-and-tested-by: Sujit Reddy Thumma <sthumma@codeaurora.org> Cc: stable@vger.kernel.org Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/ide/au1xxx-ide.c')
0 files changed, 0 insertions, 0 deletions