From: Xiao Ni Date: Thu, 30 Aug 2018 07:57:09 +0000 (+0800) Subject: RAID10 BUG_ON in raise_barrier when force is true and conf->barrier is 0 X-Git-Tag: v4.19-rc3~12^2~1 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=1d0ffd264204eba1861865560f1f7f7a92919384;p=linux.git RAID10 BUG_ON in raise_barrier when force is true and conf->barrier is 0 In raid10 reshape_request it gets max_sectors in read_balance. If the underlayer disks have bad blocks, the max_sectors is less than last. It will call goto read_more many times. It calls raise_barrier(conf, sectors_done != 0) every time. In this condition sectors_done is not 0. So the value passed to the argument force of raise_barrier is true. In raise_barrier it checks conf->barrier when force is true. If force is true and conf->barrier is 0, it panic. In this case reshape_request submits bio to under layer disks. And in the callback function of the bio it calls lower_barrier. If the bio finishes before calling raise_barrier again, it can trigger the BUG_ON. Add one pair of raise_barrier/lower_barrier to fix this bug. Signed-off-by: Xiao Ni Suggested-by: Neil Brown Signed-off-by: Shaohua Li --- diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 981898049491..d6f7978b4449 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -4529,11 +4529,12 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, allow_barrier(conf); } + raise_barrier(conf, 0); read_more: /* Now schedule reads for blocks from sector_nr to last */ r10_bio = raid10_alloc_init_r10buf(conf); r10_bio->state = 0; - raise_barrier(conf, sectors_done != 0); + raise_barrier(conf, 1); atomic_set(&r10_bio->remaining, 0); r10_bio->mddev = mddev; r10_bio->sector = sector_nr; @@ -4629,6 +4630,8 @@ static sector_t reshape_request(struct mddev *mddev, sector_t sector_nr, if (sector_nr <= last) goto read_more; + lower_barrier(conf); + /* Now that we have done the whole section we can * update reshape_progress */