bcache blocking ops and lockdep warnings

From: Sitsofe Wheeler
Date: Wed Dec 10 2014 - 01:16:04 EST


Hi,

After doing
make-bcache -B /dev/sdf
make-bcache -C /dev/sdh
ls -l /sys/fs/bcache
echo 1110734d-230c-4b8f-a63d-dff472a0977b > /sys/block/bcache0/bcache/attach

the following warnings were produced with a 3.18.0.x86_64-01967-g86c6a2f
kernel:

[ 75.218601] bcache: register_bdev() registered backing device sdf
[ 82.616568] bcache: run_cache_set() invalidating existing data
[ 82.621589] ------------[ cut here ]------------
[ 82.622890] WARNING: CPU: 1 PID: 979 at kernel/sched/core.c:7301 __might_sleep+0x5c/0xa0()
[ 82.624344] do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8155afc8>] bch_allocator_thread+0xd8/0xe30
[ 82.625979] CPU: 1 PID: 979 Comm: bcache_allocato Not tainted 3.18.0.x86_64-01967-g86c6a2f #162
[ 82.627468] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090006 05/23/2012
[ 82.628949] 0000000000000009 ffff8800da963ce8 ffffffff816ea8af 0000000000000001
[ 82.634007] ffff8800da963d38 ffff8800da963d28 ffffffff81073f3c ffff8800da963d28
[ 82.639020] ffffffff819d431c 0000000000000038 0000000000000000 ffff8800e468a680
[ 82.643967] Call Trace:
[ 82.645045] [<ffffffff816ea8af>] dump_stack+0x4e/0x68
[ 82.646345] [<ffffffff81073f3c>] warn_slowpath_common+0x7c/0xa0
[ 82.647622] [<ffffffff81073fc6>] warn_slowpath_fmt+0x46/0x50
[ 82.648954] [<ffffffff8155afc8>] ? bch_allocator_thread+0xd8/0xe30
[ 82.650338] [<ffffffff8155afc8>] ? bch_allocator_thread+0xd8/0xe30
[ 82.651667] [<ffffffff810a2e2c>] __might_sleep+0x5c/0xa0
[ 82.652959] [<ffffffff8155b0b7>] bch_allocator_thread+0x1c7/0xe30
[ 82.654335] [<ffffffff8155aef0>] ? bch_invalidate_one_bucket+0x80/0x80
[ 82.655672] [<ffffffff81091a03>] kthread+0x103/0x110
[ 82.656939] [<ffffffff81091900>] ? __kthread_unpark+0x50/0x50
[ 82.658294] [<ffffffff816f43fc>] ret_from_fork+0x7c/0xb0
[ 82.659664] [<ffffffff81091900>] ? __kthread_unpark+0x50/0x50
[ 82.660970] ---[ end trace 15295ea1be01c8a2 ]---
[ 82.683570] ------------[ cut here ]------------
[ 82.684559] WARNING: CPU: 7 PID: 974 at kernel/locking/lockdep.c:712 __lock_acquire+0x21c/0x1c60()
[ 82.684559] CPU: 7 PID: 974 Comm: bcache-register Tainted: G W 3.18.0.x86_64-01967-g86c6a2f #162
[ 82.684559] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS 090006 05/23/2012
[ 82.684559] 0000000000000009 ffff8800dac8f988 ffffffff816ea8af 0000000000000000
[ 82.684559] 0000000000000000 ffff8800dac8f9c8 ffffffff81073f3c ffff8800dac8f9c8
[ 82.684559] ffffffff82668240 0000000000000000 ffff8800dac3da88 0000000000000001
[ 82.684559] Call Trace:
[ 82.684559] [<ffffffff816ea8af>] dump_stack+0x4e/0x68
[ 82.684559] [<ffffffff81073f3c>] warn_slowpath_common+0x7c/0xa0
[ 82.684559] [<ffffffff8107403a>] warn_slowpath_null+0x1a/0x20
[ 82.684559] [<ffffffff810c0d5c>] __lock_acquire+0x21c/0x1c60
[ 82.684559] [<ffffffff813b24ae>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[ 82.684559] [<ffffffff810d624f>] ? rcu_irq_exit+0x8f/0xb0
[ 82.684559] [<ffffffff810c2706>] ? __lock_acquire+0x1bc6/0x1c60
[ 82.684559] [<ffffffff810c305c>] lock_acquire+0xfc/0x150
[ 82.684559] [<ffffffff8156346c>] ? mca_reap+0x6c/0x170
[ 82.684559] [<ffffffff810bc131>] down_write_trylock+0x61/0x80
[ 82.684559] [<ffffffff8156346c>] ? mca_reap+0x6c/0x170
[ 82.684559] [<ffffffff8156346c>] mca_reap+0x6c/0x170
[ 82.684559] [<ffffffff81563900>] mca_alloc+0xe0/0x4b0
[ 82.684559] [<ffffffff81564893>] __bch_btree_node_alloc+0xb3/0x240
[ 82.684559] [<ffffffff815760da>] run_cache_set+0x6ea/0x950
[ 82.684559] [<ffffffff8123fc6e>] ? kernfs_add_one+0x10e/0x160
[ 82.684559] [<ffffffff815780cf>] register_bcache+0x167f/0x19e0
[ 82.684559] [<ffffffff813a6bcf>] kobj_attr_store+0xf/0x20
[ 82.684559] [<ffffffff812419a8>] sysfs_kf_write+0x48/0x60
[ 82.684559] [<ffffffff81241247>] kernfs_fop_write+0xe7/0x170
[ 82.684559] [<ffffffff811cde6b>] vfs_write+0xcb/0x1d0
[ 82.684559] [<ffffffff816f50dc>] ? retint_swapgs+0x13/0x1b
[ 82.684559] [<ffffffff811ce069>] SyS_write+0x49/0xb0
[ 82.684559] [<ffffffff816f44a9>] system_call_fastpath+0x12/0x17
[ 82.684559] ---[ end trace 15295ea1be01c8a3 ]---
[ 82.763919] bcache: register_cache() registered cache device sdh

--
Sitsofe | http://sucs.org/~sits/
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