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>
diff --git a/mm/percpu.c b/mm/percpu.c
index 442010c..083e7c9 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1271,7 +1271,7 @@
*/
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 @@
if (!ptr)
return;
+ addr = __pcpu_ptr_to_addr(ptr);
+
spin_lock_irqsave(&pcpu_lock, flags);
chunk = pcpu_chunk_addr_search(addr);