From f30d704fe1244c44a984d3d1f47bc648bcc6c9f7 Mon Sep 17 00:00:00 2001
From: Benjamin LaHaise <bcrl@kvack.org>
Date: Wed, 7 Aug 2013 18:23:48 -0400
Subject: [PATCH] aio: table lookup: verify ctx pointer
Another shortcoming of the table lookup patch was revealed where the pointer
was not being tested before being dereferenced. Verify this to avoid the
NULL pointer dereference.
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
---
fs/aio.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/aio.c b/fs/aio.c
index 3bc068c1cb9c..c3f005dc2d55 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -812,7 +812,7 @@ static struct kioctx *lookup_ioctx(unsigned long ctx_id)
goto out;
ctx = table->table[id];
- if (ctx->user_id == ctx_id) {
+ if (ctx && ctx->user_id == ctx_id) {
percpu_ref_get(&ctx->users);
ret = ctx;
}