diff options
| author |   Logan Gunthorpe <logang@deltatee.com> | 2022-06-08 10:27:52 -0600 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2022-08-02 17:14:31 -0600 |
| commit | b13015af94cf405f73ff64ce0797269554020c37 (patch) | |
| tree | 7211b2f929da2c2821483cc55ad792568e4ac1d1 | |
| parent | md/raid5-cache: Drop RCU usage of conf->log (diff) | |
| download | linux-dev-b13015af94cf405f73ff64ce0797269554020c37.tar.xz linux-dev-b13015af94cf405f73ff64ce0797269554020c37.zip | |
md/raid5-cache: Clear conf->log after finishing work
A NULL pointer dereferlence on conf->log is seen randomly with
the mdadm test 21raid5cache. Kasan reporst:
BUG: KASAN: null-ptr-deref in r5l_reclaimable_space+0xf5/0x140
Read of size 8 at addr 0000000000000860 by task md0_reclaim/3086
Call Trace:
dump_stack_lvl+0x5a/0x74
kasan_report.cold+0x5f/0x1a9
__asan_load8+0x69/0x90
r5l_reclaimable_space+0xf5/0x140
r5l_do_reclaim+0xf4/0x5e0
r5l_reclaim_thread+0x69/0x3b0
md_thread+0x1a2/0x2c0
kthread+0x177/0x1b0
ret_from_fork+0x22/0x30
This is caused by conf->log being cleared in r5l_exit_log() before
stopping the reclaim thread.
To fix this, clear conf->log after the reclaim_thread is unregistered
and after flushing disable_writeback_work.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/md/raid5-cache.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/md/raid5-cache.c b/drivers/md/raid5-cache.c index d9b94e25e815..1063dccd6877 100644 --- a/drivers/md/raid5-cache.c +++ b/drivers/md/raid5-cache.c @@ -3165,12 +3165,13 @@ void r5l_exit_log(struct r5conf *conf) { struct r5l_log *log = conf->log; - conf->log = NULL; - /* Ensure disable_writeback_work wakes up and exits */ wake_up(&conf->mddev->sb_wait); flush_work(&log->disable_writeback_work); md_unregister_thread(&log->reclaim_thread); + + conf->log = NULL; + mempool_exit(&log->meta_pool); bioset_exit(&log->bs); mempool_exit(&log->io_pool); |