NFSv4: Fix a potential sleep while atomic in nfs4_do_reclaim()

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John Hubbard reports seeing the following stack trace:

nfs4_do_reclaim
   rcu_read_lock /* we are now in_atomic() and must not sleep */
       nfs4_purge_state_owners
           nfs4_free_state_owner
               nfs4_destroy_seqid_counter
                   rpc_destroy_wait_queue
                       cancel_delayed_work_sync
                           __cancel_work_timer
                               __flush_work
                                   start_flush_work
                                       might_sleep:
                                        (kernel/workqueue.c:2975: BUG)

The solution is to separate out the freeing of the state owners
from nfs4_purge_state_owners(), and perform that outside the atomic
context.

Reported-by: John Hubbard <jhubbard@nvidia.com>
Fixes: 0aaaf5c424 ("NFS: Cache state owners after files are closed")
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

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This commit is contained in:

Trond Myklebust 2019-08-03 10:11:27 -04:00

parent e3c8dc761e

commit c77e22834a

3 changed files with 28 additions and 7 deletions

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3

fs/nfs/nfs4_fs.h

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5

fs/nfs/nfs4client.c

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27

fs/nfs/nfs4state.c

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