diff options
| author | Kent Overstreet <kent.overstreet@gmail.com> | 2016-08-17 18:21:24 -0700 |
|---|---|---|
| committer | Eric Wheeler <git@linux.ewheeler.net> | 2016-08-18 20:29:49 -0700 |
| commit | acc9cf8c66c66b2cbbdb4a375537edee72be64df (patch) | |
| tree | 7a65019fbbd3727c1c9d6454b1e803a3261447ff /drivers/md | |
| parent | d9dc1702b297ec4a6bb9c0326a70641b322ba886 (diff) | |
bcache: RESERVE_PRIO is too small by one when prio_buckets() is a power of two.
This patch fixes a cachedev registration-time allocation deadlock.
This can deadlock on boot if your initrd auto-registeres bcache devices:
Allocator thread:
[ 720.727614] INFO: task bcache_allocato:3833 blocked for more than 120 seconds.
[ 720.732361] [<ffffffff816eeac7>] schedule+0x37/0x90
[ 720.732963] [<ffffffffa05192b8>] bch_bucket_alloc+0x188/0x360 [bcache]
[ 720.733538] [<ffffffff810e6950>] ? prepare_to_wait_event+0xf0/0xf0
[ 720.734137] [<ffffffffa05302bd>] bch_prio_write+0x19d/0x340 [bcache]
[ 720.734715] [<ffffffffa05190bf>] bch_allocator_thread+0x3ff/0x470 [bcache]
[ 720.735311] [<ffffffff816ee41c>] ? __schedule+0x2dc/0x950
[ 720.735884] [<ffffffffa0518cc0>] ? invalidate_buckets+0x980/0x980 [bcache]
Registration thread:
[ 720.710403] INFO: task bash:3531 blocked for more than 120 seconds.
[ 720.715226] [<ffffffff816eeac7>] schedule+0x37/0x90
[ 720.715805] [<ffffffffa05235cd>] __bch_btree_map_nodes+0x12d/0x150 [bcache]
[ 720.716409] [<ffffffffa0522d30>] ? bch_btree_insert_check_key+0x1c0/0x1c0 [bcache]
[ 720.717008] [<ffffffffa05236e4>] bch_btree_insert+0xf4/0x170 [bcache]
[ 720.717586] [<ffffffff810e6950>] ? prepare_to_wait_event+0xf0/0xf0
[ 720.718191] [<ffffffffa0527d9a>] bch_journal_replay+0x14a/0x290 [bcache]
[ 720.718766] [<ffffffff810cc90d>] ? ttwu_do_activate.constprop.94+0x5d/0x70
[ 720.719369] [<ffffffff810cf684>] ? try_to_wake_up+0x1d4/0x350
[ 720.719968] [<ffffffffa05317d0>] run_cache_set+0x580/0x8e0 [bcache]
[ 720.720553] [<ffffffffa053302e>] register_bcache+0xe2e/0x13b0 [bcache]
[ 720.721153] [<ffffffff81354cef>] kobj_attr_store+0xf/0x20
[ 720.721730] [<ffffffff812a2dad>] sysfs_kf_write+0x3d/0x50
[ 720.722327] [<ffffffff812a225a>] kernfs_fop_write+0x12a/0x180
[ 720.722904] [<ffffffff81225177>] __vfs_write+0x37/0x110
[ 720.723503] [<ffffffff81228048>] ? __sb_start_write+0x58/0x110
[ 720.724100] [<ffffffff812cedb3>] ? security_file_permission+0x23/0xa0
[ 720.724675] [<ffffffff812258a9>] vfs_write+0xa9/0x1b0
[ 720.725275] [<ffffffff8102479c>] ? do_audit_syscall_entry+0x6c/0x70
[ 720.725849] [<ffffffff81226755>] SyS_write+0x55/0xd0
[ 720.726451] [<ffffffff8106a390>] ? do_page_fault+0x30/0x80
[ 720.727045] [<ffffffff816f2cae>] system_call_fastpath+0x12/0x71
The fifo code in upstream bcache can't use the last element in the buffer,
which was the cause of the bug: if you asked for a power of two size,
it'd give you a fifo that could hold one less than what you asked for
rather than allocating a buffer twice as big.
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Tested-by: Eric Wheeler <bcache@linux.ewheeler.net>
Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/md')
| -rw-r--r-- | drivers/md/bcache/super.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c index 6ada14b9a157..6b93e1b77767 100644 --- a/drivers/md/bcache/super.c +++ b/drivers/md/bcache/super.c @@ -1820,7 +1820,7 @@ static int cache_alloc(struct cache *ca) free = roundup_pow_of_two(ca->sb.nbuckets) >> 10; if (!init_fifo(&ca->free[RESERVE_BTREE], 8, GFP_KERNEL) || - !init_fifo(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || + !init_fifo_exact(&ca->free[RESERVE_PRIO], prio_buckets(ca), GFP_KERNEL) || !init_fifo(&ca->free[RESERVE_MOVINGGC], free, GFP_KERNEL) || !init_fifo(&ca->free[RESERVE_NONE], free, GFP_KERNEL) || !init_fifo(&ca->free_inc, free << 2, GFP_KERNEL) || |