[2/2] block: Fix a race condition in submit_bio()
diff mbox series

Message ID 20190730181757.248832-3-bvanassche@acm.org
State New
Headers show
Series
  • Fix a race condition triggered by submit_bio()
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Commit Message

Bart Van Assche July 30, 2019, 6:17 p.m. UTC
generic_make_request_checks() needs to be protected by a
blk_queue_enter() / blk_queue_exit() pair because it calls
blkcg_bio_issue_check() and because that last function calls
blkg_lookup().

This patch fixes https://syzkaller.appspot.com/bug?id=ff9ab4a23afa7553fb79f745a92be87ba4144508.

This patch also fixes the following kernel warning, triggered by
blktests:

WARNING: CPU: 5 PID: 10706 at block/blk-core.c:903 generic_make_request_checks+0x9c6/0xe60
RIP: 0010:generic_make_request_checks+0x9c6/0xe60
Call Trace:
 generic_make_request+0x7a/0x5c0
 submit_bio+0x92/0x280
 mpage_readpages+0x2b1/0x300
 blkdev_readpages+0x1d/0x20
 read_pages+0xd9/0x2c0
 __do_page_cache_readahead+0x2e0/0x310
 force_page_cache_readahead+0xfb/0x170
 page_cache_sync_readahead+0x28d/0x2a0
 generic_file_read_iter+0xc13/0x1530
 blkdev_read_iter+0x7d/0x90
 new_sync_read+0x2c5/0x3d0
 __vfs_read+0x7b/0x90
 vfs_read+0xc6/0x1f0
 ksys_read+0xc3/0x160
 __x64_sys_read+0x43/0x50
 do_syscall_64+0x71/0x270
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Cc: Tejun Heo <tj@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Alexandru Moise <00moses.alexander00@gmail.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
Reported-by: syzbot+ff9ab4a23afa7553@syzkaller.appspotmail.com
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 block/blk-core.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

Comments

syzbot July 30, 2019, 6:18 p.m. UTC | #1
> generic_make_request_checks() needs to be protected by a
> blk_queue_enter() / blk_queue_exit() pair because it calls
> blkcg_bio_issue_check() and because that last function calls
> blkg_lookup().

> This patch fixes  
> https://syzkaller.appspot.com/bug?id=ff9ab4a23afa7553fb79f745a92be87ba4144508.

> This patch also fixes the following kernel warning, triggered by
> blktests:

> WARNING: CPU: 5 PID: 10706 at block/blk-core.c:903  
> generic_make_request_checks+0x9c6/0xe60
> RIP: 0010:generic_make_request_checks+0x9c6/0xe60
> Call Trace:
>   generic_make_request+0x7a/0x5c0
>   submit_bio+0x92/0x280
>   mpage_readpages+0x2b1/0x300
>   blkdev_readpages+0x1d/0x20
>   read_pages+0xd9/0x2c0
>   __do_page_cache_readahead+0x2e0/0x310
>   force_page_cache_readahead+0xfb/0x170
>   page_cache_sync_readahead+0x28d/0x2a0
>   generic_file_read_iter+0xc13/0x1530
>   blkdev_read_iter+0x7d/0x90
>   new_sync_read+0x2c5/0x3d0
>   __vfs_read+0x7b/0x90
>   vfs_read+0xc6/0x1f0
>   ksys_read+0xc3/0x160
>   __x64_sys_read+0x43/0x50
>   do_syscall_64+0x71/0x270
>   entry_SYSCALL_64_after_hwframe+0x49/0xbe

> Cc: Tejun Heo <tj@kernel.org>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Ming Lei <ming.lei@redhat.com>
> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Johannes Thumshirn <jthumshirn@suse.de>
> Cc: Alexandru Moise <00moses.alexander00@gmail.com>
> Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
> Reported-by: syzbot+ff9ab4a23afa7553@syzkaller.appspotmail.com
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
>   block/blk-core.c | 13 ++++++++++++-
>   1 file changed, 12 insertions(+), 1 deletion(-)

> diff --git a/block/blk-core.c b/block/blk-core.c
> index ff27c3080348..cd844c54e9f1 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1150,6 +1150,9 @@ EXPORT_SYMBOL_GPL(direct_make_request);
>    */
>   blk_qc_t submit_bio(struct bio *bio)
>   {
> +	struct request_queue *q = bio->bi_disk->queue;
> +	blk_qc_t ret;
> +
>   	if (blkcg_punt_bio_submit(bio))
>   		return BLK_QC_T_NONE;

> @@ -1182,7 +1185,15 @@ blk_qc_t submit_bio(struct bio *bio)
>   		}
>   	}

> -	return generic_make_request(bio);
> +	if (unlikely(blk_queue_enter(q, 0) < 0)) {
> +		bio->bi_status = BLK_STS_IOERR;
> +		bio->bi_end_io(bio);
> +		return BLK_QC_T_NONE;
> +	}
> +	ret = generic_make_request(bio);
> +	blk_queue_exit(q);
> +
> +	return ret;
>   }
>   EXPORT_SYMBOL(submit_bio);

> --
> 2.22.0.709.g102302147b-goog


I see the command but can't find the corresponding bug.
The email is sent to  syzbot+HASH@syzkaller.appspotmail.com address
but the HASH does not correspond to any known bug.
Please double check the address.
Ming Lei July 31, 2019, 1:53 a.m. UTC | #2
On Tue, Jul 30, 2019 at 11:17:57AM -0700, Bart Van Assche wrote:
> generic_make_request_checks() needs to be protected by a
> blk_queue_enter() / blk_queue_exit() pair because it calls
> blkcg_bio_issue_check() and because that last function calls
> blkg_lookup().
> 
> This patch fixes https://syzkaller.appspot.com/bug?id=ff9ab4a23afa7553fb79f745a92be87ba4144508.
> 
> This patch also fixes the following kernel warning, triggered by
> blktests:
> 
> WARNING: CPU: 5 PID: 10706 at block/blk-core.c:903 generic_make_request_checks+0x9c6/0xe60
> RIP: 0010:generic_make_request_checks+0x9c6/0xe60
> Call Trace:
>  generic_make_request+0x7a/0x5c0
>  submit_bio+0x92/0x280
>  mpage_readpages+0x2b1/0x300
>  blkdev_readpages+0x1d/0x20
>  read_pages+0xd9/0x2c0
>  __do_page_cache_readahead+0x2e0/0x310
>  force_page_cache_readahead+0xfb/0x170
>  page_cache_sync_readahead+0x28d/0x2a0
>  generic_file_read_iter+0xc13/0x1530
>  blkdev_read_iter+0x7d/0x90
>  new_sync_read+0x2c5/0x3d0
>  __vfs_read+0x7b/0x90
>  vfs_read+0xc6/0x1f0
>  ksys_read+0xc3/0x160
>  __x64_sys_read+0x43/0x50
>  do_syscall_64+0x71/0x270
>  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> 
> Cc: Tejun Heo <tj@kernel.org>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Ming Lei <ming.lei@redhat.com>
> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Johannes Thumshirn <jthumshirn@suse.de>
> Cc: Alexandru Moise <00moses.alexander00@gmail.com>
> Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
> Reported-by: syzbot+ff9ab4a23afa7553@syzkaller.appspotmail.com
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
>  block/blk-core.c | 13 ++++++++++++-
>  1 file changed, 12 insertions(+), 1 deletion(-)
> 
> diff --git a/block/blk-core.c b/block/blk-core.c
> index ff27c3080348..cd844c54e9f1 100644
> --- a/block/blk-core.c
> +++ b/block/blk-core.c
> @@ -1150,6 +1150,9 @@ EXPORT_SYMBOL_GPL(direct_make_request);
>   */
>  blk_qc_t submit_bio(struct bio *bio)
>  {
> +	struct request_queue *q = bio->bi_disk->queue;
> +	blk_qc_t ret;
> +
>  	if (blkcg_punt_bio_submit(bio))
>  		return BLK_QC_T_NONE;
>  
> @@ -1182,7 +1185,15 @@ blk_qc_t submit_bio(struct bio *bio)
>  		}
>  	}
>  
> -	return generic_make_request(bio);
> +	if (unlikely(blk_queue_enter(q, 0) < 0)) {
> +		bio->bi_status = BLK_STS_IOERR;
> +		bio->bi_end_io(bio);
> +		return BLK_QC_T_NONE;
> +	}
> +	ret = generic_make_request(bio);
> +	blk_queue_exit(q);

No, nested blk_queue_enter() is easy to cause deadlock.

Thanks,
Ming
syzbot July 31, 2019, 1:53 a.m. UTC | #3
> On Tue, Jul 30, 2019 at 11:17:57AM -0700, Bart Van Assche wrote:
>> generic_make_request_checks() needs to be protected by a
>> blk_queue_enter() / blk_queue_exit() pair because it calls
>> blkcg_bio_issue_check() and because that last function calls
>> blkg_lookup().

>> This patch fixes  
>> https://syzkaller.appspot.com/bug?id=ff9ab4a23afa7553fb79f745a92be87ba4144508.

>> This patch also fixes the following kernel warning, triggered by
>> blktests:

>> WARNING: CPU: 5 PID: 10706 at block/blk-core.c:903  
>> generic_make_request_checks+0x9c6/0xe60
>> RIP: 0010:generic_make_request_checks+0x9c6/0xe60
>> Call Trace:
>>   generic_make_request+0x7a/0x5c0
>>   submit_bio+0x92/0x280
>>   mpage_readpages+0x2b1/0x300
>>   blkdev_readpages+0x1d/0x20
>>   read_pages+0xd9/0x2c0
>>   __do_page_cache_readahead+0x2e0/0x310
>>   force_page_cache_readahead+0xfb/0x170
>>   page_cache_sync_readahead+0x28d/0x2a0
>>   generic_file_read_iter+0xc13/0x1530
>>   blkdev_read_iter+0x7d/0x90
>>   new_sync_read+0x2c5/0x3d0
>>   __vfs_read+0x7b/0x90
>>   vfs_read+0xc6/0x1f0
>>   ksys_read+0xc3/0x160
>>   __x64_sys_read+0x43/0x50
>>   do_syscall_64+0x71/0x270
>>   entry_SYSCALL_64_after_hwframe+0x49/0xbe

>> Cc: Tejun Heo <tj@kernel.org>
>> Cc: Christoph Hellwig <hch@lst.de>
>> Cc: Ming Lei <ming.lei@redhat.com>
>> Cc: Hannes Reinecke <hare@suse.com>
>> Cc: Johannes Thumshirn <jthumshirn@suse.de>
>> Cc: Alexandru Moise <00moses.alexander00@gmail.com>
>> Cc: Joseph Qi <joseph.qi@linux.alibaba.com>
>> Reported-by: syzbot+ff9ab4a23afa7553@syzkaller.appspotmail.com
>> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
>> ---
>>   block/blk-core.c | 13 ++++++++++++-
>>   1 file changed, 12 insertions(+), 1 deletion(-)

>> diff --git a/block/blk-core.c b/block/blk-core.c
>> index ff27c3080348..cd844c54e9f1 100644
>> --- a/block/blk-core.c
>> +++ b/block/blk-core.c
>> @@ -1150,6 +1150,9 @@ EXPORT_SYMBOL_GPL(direct_make_request);
>>    */
>>   blk_qc_t submit_bio(struct bio *bio)
>>   {
>> +	struct request_queue *q = bio->bi_disk->queue;
>> +	blk_qc_t ret;
>> +
>>   	if (blkcg_punt_bio_submit(bio))
>>   		return BLK_QC_T_NONE;

>> @@ -1182,7 +1185,15 @@ blk_qc_t submit_bio(struct bio *bio)
>>   		}
>>   	}

>> -	return generic_make_request(bio);
>> +	if (unlikely(blk_queue_enter(q, 0) < 0)) {
>> +		bio->bi_status = BLK_STS_IOERR;
>> +		bio->bi_end_io(bio);
>> +		return BLK_QC_T_NONE;
>> +	}
>> +	ret = generic_make_request(bio);
>> +	blk_queue_exit(q);

> No, nested blk_queue_enter() is easy to cause deadlock.

> Thanks,
> Ming

I see the command but can't find the corresponding bug.
The email is sent to  syzbot+HASH@syzkaller.appspotmail.com address
but the HASH does not correspond to any known bug.
Please double check the address.

Patch
diff mbox series

diff --git a/block/blk-core.c b/block/blk-core.c
index ff27c3080348..cd844c54e9f1 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1150,6 +1150,9 @@  EXPORT_SYMBOL_GPL(direct_make_request);
  */
 blk_qc_t submit_bio(struct bio *bio)
 {
+	struct request_queue *q = bio->bi_disk->queue;
+	blk_qc_t ret;
+
 	if (blkcg_punt_bio_submit(bio))
 		return BLK_QC_T_NONE;
 
@@ -1182,7 +1185,15 @@  blk_qc_t submit_bio(struct bio *bio)
 		}
 	}
 
-	return generic_make_request(bio);
+	if (unlikely(blk_queue_enter(q, 0) < 0)) {
+		bio->bi_status = BLK_STS_IOERR;
+		bio->bi_end_io(bio);
+		return BLK_QC_T_NONE;
+	}
+	ret = generic_make_request(bio);
+	blk_queue_exit(q);
+
+	return ret;
 }
 EXPORT_SYMBOL(submit_bio);