diff options
| author | Nikolay Borisov <kernel@kyup.com> | 2016-10-11 12:04:09 +0300 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2016-12-13 01:54:27 +0300 |
| commit | 5c341ee32881c554727ec14b71ec3e8832f01989 (patch) | |
| tree | b349637c1fbc4a44346d23428a6836086ce6bd0f /fs/ceph/caps.c | |
| parent | a380a031cbe4323a3f638a8468c862510ace1919 (diff) | |
| download | linux-5c341ee32881c554727ec14b71ec3e8832f01989.tar.xz | |
ceph: fix scheduler warning due to nested blocking
try_get_cap_refs can be used as a condition in a wait_event* calls.
This is all fine until it has to call __ceph_do_pending_vmtruncate,
which in turn acquires the i_truncate_mutex. This leads to a situation
in which a task's state is !TASK_RUNNING and at the same time it's
trying to acquire a sleeping primitive. In essence a nested sleeping
primitives are being used. This causes the following warning:
WARNING: CPU: 22 PID: 11064 at kernel/sched/core.c:7631 __might_sleep+0x9f/0xb0()
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8109447d>] prepare_to_wait_event+0x5d/0x110
ipmi_msghandler tcp_scalable ib_qib dca ib_mad ib_core ib_addr ipv6
CPU: 22 PID: 11064 Comm: fs_checker.pl Tainted: G O 4.4.20-clouder2 #6
Hardware name: Supermicro X10DRi/X10DRi, BIOS 1.1a 10/16/2015
0000000000000000 ffff8838b416fa88 ffffffff812f4409 ffff8838b416fad0
ffffffff81a034f2 ffff8838b416fac0 ffffffff81052b46 ffffffff81a0432c
0000000000000061 0000000000000000 0000000000000000 ffff88167bda54a0
Call Trace:
[<ffffffff812f4409>] dump_stack+0x67/0x9e
[<ffffffff81052b46>] warn_slowpath_common+0x86/0xc0
[<ffffffff81052bcc>] warn_slowpath_fmt+0x4c/0x50
[<ffffffff8109447d>] ? prepare_to_wait_event+0x5d/0x110
[<ffffffff8109447d>] ? prepare_to_wait_event+0x5d/0x110
[<ffffffff8107767f>] __might_sleep+0x9f/0xb0
[<ffffffff81612d30>] mutex_lock+0x20/0x40
[<ffffffffa04eea14>] __ceph_do_pending_vmtruncate+0x44/0x1a0 [ceph]
[<ffffffffa04fa692>] try_get_cap_refs+0xa2/0x320 [ceph]
[<ffffffffa04fd6f5>] ceph_get_caps+0x255/0x2b0 [ceph]
[<ffffffff81094370>] ? wait_woken+0xb0/0xb0
[<ffffffffa04f2c11>] ceph_write_iter+0x2b1/0xde0 [ceph]
[<ffffffff81613f22>] ? schedule_timeout+0x202/0x260
[<ffffffff8117f01a>] ? kmem_cache_free+0x1ea/0x200
[<ffffffff811b46ce>] ? iput+0x9e/0x230
[<ffffffff81077632>] ? __might_sleep+0x52/0xb0
[<ffffffff81156147>] ? __might_fault+0x37/0x40
[<ffffffff8119e123>] ? cp_new_stat+0x153/0x170
[<ffffffff81198cfa>] __vfs_write+0xaa/0xe0
[<ffffffff81199369>] vfs_write+0xa9/0x190
[<ffffffff811b6d01>] ? set_close_on_exec+0x31/0x70
[<ffffffff8119a056>] SyS_write+0x46/0xa0
This happens since wait_event_interruptible can interfere with the
mutex locking code, since they both fiddle with the task state.
Fix the issue by using the newly-added nested blocking infrastructure
in 61ada528dea0 ("sched/wait: Provide infrastructure to deal with
nested blocking")
Link: https://lwn.net/Articles/628628/
Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Yan, Zheng <zyan@redhat.com>
Diffstat (limited to 'fs/ceph/caps.c')
| -rw-r--r-- | fs/ceph/caps.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c index 16e6ded0b7f2..4037b389a7e9 100644 --- a/fs/ceph/caps.c +++ b/fs/ceph/caps.c @@ -2507,9 +2507,15 @@ int ceph_get_caps(struct ceph_inode_info *ci, int need, int want, if (err < 0) ret = err; } else { - ret = wait_event_interruptible(ci->i_cap_wq, - try_get_cap_refs(ci, need, want, endoff, - true, &_got, &err)); + DEFINE_WAIT_FUNC(wait, woken_wake_function); + add_wait_queue(&ci->i_cap_wq, &wait); + + while (!try_get_cap_refs(ci, need, want, endoff, + true, &_got, &err)) + wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); + + remove_wait_queue(&ci->i_cap_wq, &wait); + if (err == -EAGAIN) continue; if (err < 0) |