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| author | Joseph Qi <qijiang.qj@alibaba-inc.com> | 2017-06-07 06:36:14 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2017-06-07 17:11:24 +0300 |
| commit | a41b816c174409417d91b4ceef0145c9f0bef67c (patch) | |
| tree | 82b3b4311eb770dfd22e25fb9e67cff08d885c4f | |
| parent | 9bd2bbc01d17ddd567cc0f81f77fe1163e497462 (diff) | |
| download | linux-a41b816c174409417d91b4ceef0145c9f0bef67c.tar.xz | |
blk-throttle: fix NULL pointer dereference in throtl_schedule_pending_timer
I have encountered a NULL pointer dereference in
throtl_schedule_pending_timer:
[ 413.735396] BUG: unable to handle kernel NULL pointer dereference at 0000000000000038
[ 413.735535] IP: [<ffffffff812ebbbf>] throtl_schedule_pending_timer+0x3f/0x210
[ 413.735643] PGD 22c8cf067 PUD 22cb34067 PMD 0
[ 413.735713] Oops: 0000 [#1] SMP
......
This is caused by the following case:
blk_throtl_bio
throtl_schedule_next_dispatch <= sq is top level one without parent
throtl_schedule_pending_timer
sq_to_tg(sq)->td->throtl_slice <= sq_to_tg(sq) returns NULL
Fix it by using sq_to_td instead of sq_to_tg(sq)->td, which will always
return a valid td.
Fixes: 297e3d854784 ("blk-throttle: make throtl_slice tunable")
Signed-off-by: Joseph Qi <qijiang.qj@alibaba-inc.com>
Reviewed-by: Shaohua Li <shli@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
| -rw-r--r-- | block/blk-throttle.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index fc13dd0c6e39..3b751f706c61 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -698,7 +698,7 @@ static void throtl_dequeue_tg(struct throtl_grp *tg) static void throtl_schedule_pending_timer(struct throtl_service_queue *sq, unsigned long expires) { - unsigned long max_expire = jiffies + 8 * sq_to_tg(sq)->td->throtl_slice; + unsigned long max_expire = jiffies + 8 * sq_to_td(sq)->throtl_slice; /* * Since we are adjusting the throttle limit dynamically, the sleep |