From c77e22834ae9a11891cb613bd9a551be1b94f2bc Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sat, 3 Aug 2019 10:11:27 -0400 Subject: NFSv4: Fix a potential sleep while atomic in nfs4_do_reclaim() 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 Fixes: 0aaaf5c424c7f ("NFS: Cache state owners after files are closed") Signed-off-by: Trond Myklebust --- fs/nfs/nfs4client.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'fs/nfs/nfs4client.c') diff --git a/fs/nfs/nfs4client.c b/fs/nfs/nfs4client.c index 616393a01c06..da6204025a2d 100644 --- a/fs/nfs/nfs4client.c +++ b/fs/nfs/nfs4client.c @@ -758,9 +758,12 @@ out: static void nfs4_destroy_server(struct nfs_server *server) { + LIST_HEAD(freeme); + nfs_server_return_all_delegations(server); unset_pnfs_layoutdriver(server); - nfs4_purge_state_owners(server); + nfs4_purge_state_owners(server, &freeme); + nfs4_free_state_owners(&freeme); } /* -- cgit v1.2.3-55-g7522