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@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Ming Lei <ming.lei@xxxxxxxxxx>
Cc: Hannes Reinecke <hare@xxxxxxxx>
Cc: Johannes Thumshirn <jthumshirn@xxxxxxx>
Cc: Alexandru Moise <00moses.alexander00@xxxxxxxxx>
Cc: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>
Reported-by: syzbot+ff9ab4a23afa7553@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
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@xxxxxxxxxxxxxxxxxxxxxxxxx address
but the HASH does not correspond to any known bug.
Please double check the address.
