Thread (314 messages) flat view 314 messages, 6 authors, 2021-03-19
STALE1994d

[PATCH 5.11 245/306] SUNRPC: Set memalloc_nofs_save() for sync tasks

From: gregkh@linuxfoundation.org
Date: 2021-03-15 14:49:38
Also in: lkml
Subsystem: kernel nfsd, sunrpc, and lockd servers, networking [general], nfs, sunrpc, and lockd clients, the rest · Maintainers: Chuck Lever, Jeff Layton, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Trond Myklebust, Anna Schumaker, Linus Torvalds

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

From: Benjamin Coddington <redacted>

[ Upstream commit f0940f4b3284a00f38a5d42e6067c2aaa20e1f2e ]

We could recurse into NFS doing memory reclaim while sending a sync task,
which might result in a deadlock.  Set memalloc_nofs_save for sync task
execution.

Fixes: a1231fda7e94 ("SUNRPC: Set memalloc_nofs_save() on all rpciod/xprtiod jobs")
Signed-off-by: Benjamin Coddington <redacted>
Signed-off-by: Anna Schumaker <redacted>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 net/sunrpc/sched.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index cf702a5f7fe5..39ed0e0afe6d 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -963,8 +963,11 @@ void rpc_execute(struct rpc_task *task)
 
 	rpc_set_active(task);
 	rpc_make_runnable(rpciod_workqueue, task);
-	if (!is_async)
+	if (!is_async) {
+		unsigned int pflags = memalloc_nofs_save();
 		__rpc_execute(task);
+		memalloc_nofs_restore(pflags);
+	}
 }
 
 static void rpc_async_schedule(struct work_struct *work)
-- 
2.30.1


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