| Message ID | 20230921182012.3965572-1-saranyamohan@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | block: fix use-after-free of q->q_usage_counter | expand |
On Thu, Sep 21, 2023 at 11:20:12AM -0700, Saranya Muruganandam wrote: > From: Ming Lei <ming.lei@redhat.com> > > commit d36a9ea5e7766961e753ee38d4c331bbe6ef659b upstream. > > For blk-mq, queue release handler is usually called after > blk_mq_freeze_queue_wait() returns. However, the > q_usage_counter->release() handler may not be run yet at that time, so > this can cause a use-after-free. > > Fix the issue by moving percpu_ref_exit() into blk_free_queue_rcu(). > Since ->release() is called with rcu read lock held, it is agreed that > the race should be covered in caller per discussion from the two links. > > Backport-notes: Not a clean cherry-pick since a lot has changed, > however essentially the same fix. > > Reported-by: Zhang Wensheng <zhangwensheng@huaweicloud.com> > Reported-by: Zhong Jinghua <zhongjinghua@huawei.com> > Link: https://lore.kernel.org/linux-block/Y5prfOjyyjQKUrtH@T590/T/#u > Link: https://lore.kernel.org/lkml/Y4%2FmzMd4evRg9yDi@fedora/ > Cc: Hillf Danton <hdanton@sina.com> > Cc: Yu Kuai <yukuai3@huawei.com> > Cc: Dennis Zhou <dennis@kernel.org> > Fixes: 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path") > Signed-off-by: Ming Lei <ming.lei@redhat.com> > Link: https://lore.kernel.org/r/20221215021629.74870-1-ming.lei@redhat.com > Signed-off-by: Jens Axboe <axboe@kernel.dk> > Signed-off-by: Saranya Muruganandam <saranyamohan@google.com> > --- > block/blk-core.c | 2 -- > block/blk-sysfs.c | 2 ++ > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/block/blk-core.c b/block/blk-core.c > index d0d0dd8151f7..e5eeec801f56 100644 > --- a/block/blk-core.c > +++ b/block/blk-core.c > @@ -414,8 +414,6 @@ void blk_cleanup_queue(struct request_queue *q) > blk_mq_sched_free_requests(q); > mutex_unlock(&q->sysfs_lock); > > - percpu_ref_exit(&q->q_usage_counter); > - > /* @q is and will stay empty, shutdown and put */ > blk_put_queue(q); > } > diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c > index 8c5816364dd1..9174137a913c 100644 > --- a/block/blk-sysfs.c > +++ b/block/blk-sysfs.c > @@ -726,6 +726,8 @@ static void blk_free_queue_rcu(struct rcu_head *rcu_head) > { > struct request_queue *q = container_of(rcu_head, struct request_queue, > rcu_head); > + > + percpu_ref_exit(&q->q_usage_counter); > kmem_cache_free(blk_requestq_cachep, q); > } Looks fine. BTW, you should have provided target stable tree release info, otherwise how you expect people to review? Thanks, Ming
On Thu, Sep 21, 2023 at 11:20:12AM -0700, Saranya Muruganandam wrote: > From: Ming Lei <ming.lei@redhat.com> > > commit d36a9ea5e7766961e753ee38d4c331bbe6ef659b upstream. > > For blk-mq, queue release handler is usually called after > blk_mq_freeze_queue_wait() returns. However, the > q_usage_counter->release() handler may not be run yet at that time, so > this can cause a use-after-free. > > Fix the issue by moving percpu_ref_exit() into blk_free_queue_rcu(). > Since ->release() is called with rcu read lock held, it is agreed that > the race should be covered in caller per discussion from the two links. > > Backport-notes: Not a clean cherry-pick since a lot has changed, > however essentially the same fix. > > Reported-by: Zhang Wensheng <zhangwensheng@huaweicloud.com> > Reported-by: Zhong Jinghua <zhongjinghua@huawei.com> > Link: https://lore.kernel.org/linux-block/Y5prfOjyyjQKUrtH@T590/T/#u > Link: https://lore.kernel.org/lkml/Y4%2FmzMd4evRg9yDi@fedora/ > Cc: Hillf Danton <hdanton@sina.com> > Cc: Yu Kuai <yukuai3@huawei.com> > Cc: Dennis Zhou <dennis@kernel.org> > Fixes: 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path") > Signed-off-by: Ming Lei <ming.lei@redhat.com> > Link: https://lore.kernel.org/r/20221215021629.74870-1-ming.lei@redhat.com > Signed-off-by: Jens Axboe <axboe@kernel.dk> > Signed-off-by: Saranya Muruganandam <saranyamohan@google.com> > --- > block/blk-core.c | 2 -- > block/blk-sysfs.c | 2 ++ > 2 files changed, 2 insertions(+), 2 deletions(-) What stable kernel(s) are you expecting this backport to be applied to? thanks, greg "not a mind reader" k-h
Apologies for leaving out the stable release info. This is for both 5.10 and patch applies cleanly for 5.15. I just sent out a (different) modified patch for 6.1 LTS. On Fri, Sep 22, 2023 at 2:26 AM Greg KH <gregkh@linuxfoundation.org> wrote: > > On Thu, Sep 21, 2023 at 11:20:12AM -0700, Saranya Muruganandam wrote: > > From: Ming Lei <ming.lei@redhat.com> > > > > commit d36a9ea5e7766961e753ee38d4c331bbe6ef659b upstream. > > > > For blk-mq, queue release handler is usually called after > > blk_mq_freeze_queue_wait() returns. However, the > > q_usage_counter->release() handler may not be run yet at that time, so > > this can cause a use-after-free. > > > > Fix the issue by moving percpu_ref_exit() into blk_free_queue_rcu(). > > Since ->release() is called with rcu read lock held, it is agreed that > > the race should be covered in caller per discussion from the two links. > > > > Backport-notes: Not a clean cherry-pick since a lot has changed, > > however essentially the same fix. > > > > Reported-by: Zhang Wensheng <zhangwensheng@huaweicloud.com> > > Reported-by: Zhong Jinghua <zhongjinghua@huawei.com> > > Link: https://lore.kernel.org/linux-block/Y5prfOjyyjQKUrtH@T590/T/#u > > Link: https://lore.kernel.org/lkml/Y4%2FmzMd4evRg9yDi@fedora/ > > Cc: Hillf Danton <hdanton@sina.com> > > Cc: Yu Kuai <yukuai3@huawei.com> > > Cc: Dennis Zhou <dennis@kernel.org> > > Fixes: 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path") > > Signed-off-by: Ming Lei <ming.lei@redhat.com> > > Link: https://lore.kernel.org/r/20221215021629.74870-1-ming.lei@redhat.com > > Signed-off-by: Jens Axboe <axboe@kernel.dk> > > Signed-off-by: Saranya Muruganandam <saranyamohan@google.com> > > --- > > block/blk-core.c | 2 -- > > block/blk-sysfs.c | 2 ++ > > 2 files changed, 2 insertions(+), 2 deletions(-) > > What stable kernel(s) are you expecting this backport to be applied to? > > thanks, > > greg "not a mind reader" k-h
On Fri, Sep 22, 2023 at 11:21:10AM -0700, Saranya Muruganandam wrote: > Apologies for leaving out the stable release info. > This is for both 5.10 and patch applies cleanly for 5.15. > > I just sent out a (different) modified patch for 6.1 LTS. All now queued up, thanks. greg k-h
diff --git a/block/blk-core.c b/block/blk-core.c index d0d0dd8151f7..e5eeec801f56 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -414,8 +414,6 @@ void blk_cleanup_queue(struct request_queue *q) blk_mq_sched_free_requests(q); mutex_unlock(&q->sysfs_lock); - percpu_ref_exit(&q->q_usage_counter); - /* @q is and will stay empty, shutdown and put */ blk_put_queue(q); } diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 8c5816364dd1..9174137a913c 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -726,6 +726,8 @@ static void blk_free_queue_rcu(struct rcu_head *rcu_head) { struct request_queue *q = container_of(rcu_head, struct request_queue, rcu_head); + + percpu_ref_exit(&q->q_usage_counter); kmem_cache_free(blk_requestq_cachep, q); }