From: xiao jin <[email protected]>
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: <[email protected]>
Reviewed-by: Ming Lei <[email protected]>
Reviewed-by: Bart Van Assche <[email protected]>
Signed-off-by: xiao jin <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Signed-off-by: Alessio Balsini <[email protected]>
---
block/blk-core.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/block/blk-core.c b/block/blk-core.c
index 50d77c90070d..7662f97dded6 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -870,6 +870,7 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
fail:
blk_free_flush_queue(q->fq);
+ q->fq = NULL;
return NULL;
}
EXPORT_SYMBOL(blk_init_allocated_queue);
--
2.22.0.770.g0f2c4a37fd-goog
On Thu, Aug 08, 2019 at 03:28:19AM +0100, Alessio Balsini wrote:
> From: xiao jin <[email protected]>
>
> 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: <[email protected]>
> Reviewed-by: Ming Lei <[email protected]>
> Reviewed-by: Bart Van Assche <[email protected]>
> Signed-off-by: xiao jin <[email protected]>
> Signed-off-by: Jens Axboe <[email protected]>
> Signed-off-by: Alessio Balsini <[email protected]>
> ---
> block/blk-core.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/block/blk-core.c b/block/blk-core.c
> index 50d77c90070d..7662f97dded6 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -870,6 +870,7 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
>
> fail:
> blk_free_flush_queue(q->fq);
> + q->fq = NULL;
> return NULL;
> }
> EXPORT_SYMBOL(blk_init_allocated_queue);
> --
> 2.22.0.770.g0f2c4a37fd-goog
>
Guenter sent this backport a day before you did, so I took his version
and added your s-o-b to it.
thanks,
greg k-h
Oops, thanks!
On Thu, Aug 8, 2019 at 2:00 AM Greg KH <[email protected]> wrote:
>
> On Thu, Aug 08, 2019 at 03:28:19AM +0100, Alessio Balsini wrote:
> > From: xiao jin <[email protected]>
> >
> > 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: <[email protected]>
> > Reviewed-by: Ming Lei <[email protected]>
> > Reviewed-by: Bart Van Assche <[email protected]>
> > Signed-off-by: xiao jin <[email protected]>
> > Signed-off-by: Jens Axboe <[email protected]>
> > Signed-off-by: Alessio Balsini <[email protected]>
> > ---
> > block/blk-core.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/block/blk-core.c b/block/blk-core.c
> > index 50d77c90070d..7662f97dded6 100644
> > --- a/block/blk-core.c
> > +++ b/block/blk-core.c
> > @@ -870,6 +870,7 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
> >
> > fail:
> > blk_free_flush_queue(q->fq);
> > + q->fq = NULL;
> > return NULL;
> > }
> > EXPORT_SYMBOL(blk_init_allocated_queue);
> > --
> > 2.22.0.770.g0f2c4a37fd-goog
> >
>
> Guenter sent this backport a day before you did, so I took his version
> and added your s-o-b to it.
>
> thanks,
>
> greg k-h