diff options
| author | Ming Lei <ming.lei@canonical.com> | 2016-11-16 18:07:05 +0800 |
|---|---|---|
| committer | Huang, Tao <huangtao@rock-chips.com> | 2017-09-15 09:40:14 +0800 |
| commit | 675e170adc0eb470949cc11bb482b52b5dddadda (patch) | |
| tree | 070f02a874d5795f01631bed35dbf162bfc5eaf0 /block | |
| parent | 331eee6d7ee99b8869ccd6f7f2e47edb07b35d55 (diff) | |
UPSTREAM: block: deal with stale req count of plug list
In both legacy and mq path, req count of plug list is computed
before allocating request, so the number can be stale when falling
back to slept allocation, also the new introduced wbt can sleep
too.
This patch deals with the case by checking if plug list becomes
empty, and fixes the KASAN report of 'BUG: KASAN: stack-out-of-bounds'
which is introduced by Shaohua's patches of dispatching big request.
Change-Id: I00cdd180e44574aeb7167266b3aa04a28cf4cdc6
Fixes: 600271d900002(blk-mq: immediately dispatch big size request)
Fixes: 50d24c34403c6(block: immediately dispatch big size request)
Cc: Shaohua Li <shli@fb.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
(cherry pick from 0a6219a95f0b0690fb7094acb26002e7a4791197)
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-core.c | 5 | ||||
| -rw-r--r-- | block/blk-mq.c | 7 |
2 files changed, 11 insertions, 1 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index b3c48aaa6dc0..80a33af0050d 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1796,8 +1796,11 @@ get_rq: /* * If this is the first request added after a plug, fire * of a plug trace. + * + * @request_count may become stale because of schedule + * out, so check plug list again. */ - if (!request_count) + if (!request_count || list_empty(&plug->list)) trace_block_plug(q); else { struct request *last = list_entry_rq(plug->list.prev); diff --git a/block/blk-mq.c b/block/blk-mq.c index aaea6ea66fac..434cb5f7d9ae 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1380,6 +1380,13 @@ static blk_qc_t blk_sq_make_request(struct request_queue *q, struct bio *bio) struct request *last = NULL; blk_mq_bio_to_request(rq, bio); + + /* + * @request_count may become stale because of schedule + * out, so check the list again. + */ + if (list_empty(&plug->mq_list)) + request_count = 0; if (!request_count) trace_block_plug(q); else |