block: blk_init_allocated_queue() set q->fq as NULL in the fail case
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
Fixes: commit 7c94e1c157a2 ("block: introduce blk_flush_queue to drive flush machinery")
Reviewed-by: Ming Lei <firstname.lastname@example.org>
Reviewed-by: Bart Van Assche <email@example.com>
Signed-off-by: xiao jin <firstname.lastname@example.org>
Signed-off-by: Jens Axboe <email@example.com>
[groeck: backport to v4.4.y/v4.9.y (context change)]
Signed-off-by: Guenter Roeck <firstname.lastname@example.org>
Signed-off-by: Alessio Balsini <email@example.com>
Signed-off-by: Greg Kroah-Hartman <firstname.lastname@example.org>
1 file changed