[PATCH] ipc: don't allocate with GFP_KERNEL inside rcu read lock

[Sasha Levin]

ipc_addid() is protected by a rcu read lock, which means we can't allocate
using GFP_KERNEL inside it.

Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---

Another option would be to call idr_preload from outside the read lock,
but that complicates the code much more than this fix. If that's the
preferred method to fix it I can resend that solution instead.

 ipc/util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ipc/util.c b/ipc/util.c
index a746abb..00aca85 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -261,7 +261,7 @@ int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size)
 	if (ids->in_use >= size)
 		return -ENOSPC;
 
-	idr_preload(GFP_KERNEL);
+	idr_preload(GFP_ATOMIC);
 
 	spin_lock_init(&new->lock);
 	new->deleted = 0;
-- 
1.8.1.2

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