he function blk_get_request() can return NULL in some cases. There are
checks on it if function is called with argumetns one of which is
GFP_ATOMIC/GFP_NOIO/etc. If system couldn't find request
blk_get_request() return NULL.
But if there is function call with argument __GFP_WAIT
the system will wait until get request or the queue becomes
dead. If something kills the queue, blk_get_request()
return NULL and next operations will lead to errors.
Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: Marina Makienko <makie...@ispras.ru>
---
drivers/ide/ide-pm.c | 6 ++++++
1 files changed, 6 insertions(+), 0 deletions(-)
diff --git a/drivers/ide/ide-pm.c b/drivers/ide/ide-pm.c
index 9240609..4412f24 100644
--- a/drivers/ide/ide-pm.c
+++ b/drivers/ide/ide-pm.c
@@ -19,6 +19,10 @@ int generic_ide_suspend(struct device *dev, pm_message_t
mesg)
memset(&rqpm, 0, sizeof(rqpm));
rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
+
+ if (!rq)
+ return -EIO;
+
rq->cmd_type = REQ_TYPE_PM_SUSPEND;
rq->special = &rqpm;
rqpm.pm_step = IDE_PM_START_SUSPEND;
@@ -59,6 +63,8 @@ int generic_ide_resume(struct device *dev)
memset(&rqpm, 0, sizeof(rqpm));
rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
+ if (!rq)
+ return -EIO;
rq->cmd_type = REQ_TYPE_PM_RESUME;
rq->cmd_flags |= REQ_PREEMPT;
rq->special = &rqpm;
--
1.7.7
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