From 502ee4793f4dede6a36df896e832e1dcdef32cba Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Fri, 8 Jan 2010 14:42:39 -0800
Subject: [PATCH] percpu: avoid calling __pcpu_ptr_to_addr(NULL)
__pcpu_ptr_to_addr() can be overridden by the architecture and might not
behave well if passed a NULL pointer. So avoid calling it until we have
verified that its arg is not NULL.
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/percpu.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/mm/percpu.c b/mm/percpu.c
index 442010cc91c6c..083e7c91e5f62 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1271,7 +1271,7 @@ static void pcpu_reclaim(struct work_struct *work)
*/
void free_percpu(void *ptr)
{
- void *addr = __pcpu_ptr_to_addr(ptr);
+ void *addr;
struct pcpu_chunk *chunk;
unsigned long flags;
int off;
@@ -1279,6 +1279,8 @@ void free_percpu(void *ptr)
if (!ptr)
return;
+ addr = __pcpu_ptr_to_addr(ptr);
+
spin_lock_irqsave(&pcpu_lock, flags);
chunk = pcpu_chunk_addr_search(addr);
--
2.39.5