Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 14/21] block: blk_init_allocated_queue() set q->fq as NULL in the fail case | Date | Fri, 9 Aug 2019 15:45:18 +0200 |
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From: xiao jin <jin.xiao@intel.com>
commit 54648cf1ec2d7f4b6a71767799c45676a138ca24 upstream.
We find the memory use-after-free issue in __blk_drain_queue() on the kernel 4.14. After read the latest kernel 4.18-rc6 we think it has the same problem.
Memory is allocated for q->fq in the blk_init_allocated_queue(). If the elevator init function called with error return, it will run into the fail case to free the q->fq.
Then the __blk_drain_queue() uses the same memory after the free of the q->fq, it will lead to the unpredictable event.
The patch is to set q->fq as NULL in the fail case of blk_init_allocated_queue().
Fixes: commit 7c94e1c157a2 ("block: introduce blk_flush_queue to drive flush machinery") Cc: <stable@vger.kernel.org> Reviewed-by: Ming Lei <ming.lei@redhat.com> Reviewed-by: Bart Van Assche <bart.vanassche@wdc.com> Signed-off-by: xiao jin <jin.xiao@intel.com> Signed-off-by: Jens Axboe <axboe@kernel.dk> [groeck: backport to v4.4.y/v4.9.y (context change)] Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Alessio Balsini <balsini@android.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- block/blk-core.c | 1 + 1 file changed, 1 insertion(+)
--- a/block/blk-core.c +++ b/block/blk-core.c @@ -870,6 +870,7 @@ blk_init_allocated_queue(struct request_ fail: blk_free_flush_queue(q->fq); + q->fq = NULL; return NULL; } EXPORT_SYMBOL(blk_init_allocated_queue);
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