From 9c21dae291d1b7763b749dfaef3fb911286c0d98 Mon Sep 17 00:00:00 2001
From: Davidlohr Bueso <dbueso@suse.de>
Date: Tue, 4 Sep 2018 15:46:02 -0700
Subject: [PATCH] ipc/shm: properly return EIDRM in shm_lock()

When getting rid of the general ipc_lock(), this was missed furthermore,
making the comment around the ipc object validity check bogus.  Under
EIDRM conditions, callers will in turn not see the error and continue
with the operation.

Link: http://lkml.kernel.org/r/20180824030920.GD3677@linux-r8p5
Link: http://lkml.kernel.org/r/20180823024051.GC13343@shao2-debian
Fixes: 82061c57ce9 ("ipc: drop ipc_lock()")
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Reported-by: kernel test robot <rong.a.chen@intel.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 ipc/shm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/ipc/shm.c b/ipc/shm.c
index b0eb3757ab89..4cd402e4cfeb 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -199,6 +199,7 @@ static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
 	}
 
 	ipc_unlock_object(ipcp);
+	ipcp = ERR_PTR(-EIDRM);
 err:
 	rcu_read_unlock();
 	/*