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Message-Id: <1344520529-19164-3-git-send-email-makienko@ispras.ru>
Date: Thu, 9 Aug 2012 17:55:22 +0400
From: Marina Makienko <makienko@...ras.ru>
To: "David S. Miller" <davem@...emloft.net>
Cc: Marina Makienko <makienko@...ras.ru>, linux-ide@...r.kernel.org,
linux-kernel@...r.kernel.org, ldv-project@...ras.ru
Subject: [PATCH 05/13] ide: Potential null pointer dereference in ide_raw_taskfile()
The 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@...ras.ru>
---
drivers/ide/ide-taskfile.c | 4 ++++
1 files changed, 4 insertions(+), 0 deletions(-)
diff --git a/drivers/ide/ide-taskfile.c b/drivers/ide/ide-taskfile.c
index 729428e..655d894 100644
--- a/drivers/ide/ide-taskfile.c
+++ b/drivers/ide/ide-taskfile.c
@@ -432,6 +432,10 @@ int ide_raw_taskfile(ide_drive_t *drive, struct ide_cmd *cmd, u8 *buf,
int rw = !(cmd->tf_flags & IDE_TFLAG_WRITE) ? READ : WRITE;
rq = blk_get_request(drive->queue, rw, __GFP_WAIT);
+
+ if (!rq)
+ return -EIO;
+
rq->cmd_type = REQ_TYPE_ATA_TASKFILE;
/*
--
1.7.7
--
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