[LU-12193] possible scheduling with spinlocks held in the quota paths

• Type: Bug
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.14.0
• Severity: 3
• Assignee: Sergey Cheremencev
• Reporter: Alex Zhuravlev

Description

this looks very dangerous:

[<ffffffff815f11f9>] _cond_resched+0x29/0x40
[<ffffffffa04f2c9b>] ptlrpc_check_set+0x16b/0x30a0 [ptlrpc]
[<ffffffffa04f5d2a>] ptlrpc_set_wait+0x15a/0x7b0 [ptlrpc]
[<ffffffff8137da0d>] ? __raw_spin_lock_init+0x2d/0x50
[<ffffffffa04ad520>] ? __ldlm_handle2lock+0x3f0/0x3f0 [ptlrpc]
[<ffffffffa04ec1d0>] ? ptlrpc_prep_set+0x180/0x2b0 [ptlrpc]
[<ffffffffa04b3197>] ldlm_run_ast_work+0xd7/0x3d0 [ptlrpc]
[<ffffffffa04d6006>] ldlm_glimpse_locks+0x36/0xf0 [ptlrpc]
[<ffffffffa0880d8a>] qmt_glimpse_lock.isra.2.constprop.4+0x52a/0xa70 [lquota]
[<ffffffffa0884445>] qmt_glb_lock_notify+0x1e5/0x390 [lquota]
[<ffffffffa087de2f>] qmt_set_with_lqe+0x35f/0x800 [lquota]
[<ffffffffa087e2d0>] ? qmt_set_with_lqe+0x800/0x800 [lquota]
[<ffffffffa087e326>] qmt_entry_iter_cb+0x56/0xa0 [lquota]
[<ffffffffa000e53b>] cfs_hash_for_each_tight+0x10b/0x2e0 [libcfs]
[<ffffffffa000e75e>] cfs_hash_for_each_safe+0xe/0x10 [libcfs]
[<ffffffffa087de7f>] qmt_set_with_lqe+0x3af/0x800 [lquota]
[<ffffffffa087e4b8>] qmt_set.constprop.2+0x148/0x2b0 [lquota]
[<ffffffffa0556dce>] ? barrier_entry+0x3e/0x180 [ptlrpc]
[<ffffffffa087ec03>] qmt_quotactl+0x5e3/0x600 [lquota]
[<ffffffffa0a93400>] mdt_quotactl+0x290/0x770 [mdt]