Patchwork [06/13] ide: Potential null pointer dereference in generic_ide_resume()

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Submitter Marina Makienko
Date Aug. 9, 2012, 1:55 p.m.
Message ID <1344520529-19164-4-git-send-email-makienko@ispras.ru>
Download mbox | patch
Permalink /patch/176112/
State Rejected
Delegated to: David Miller
Headers show

Comments

Marina Makienko - Aug. 9, 2012, 1:55 p.m.
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 <makienko@ispras.ru>
---
 drivers/ide/ide-pm.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

Patch

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;