Re: [PATCH] zram: fix null dereference of handle

From: Sergey Senozhatsky
Date: Tue Sep 19 2017 - 06:21:35 EST


Minchan,

I just ran across it [because I had a bug to analize where this
part was involved]. I'd really prefer the kernel to BUG_ON immediately
instead of dying in agony.

can we, please, return BUG_ON() back?

there is no point in trying to save the kernel once it did that type
of violation.

---

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 7c38e850a8fc..685049a9048d 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -1349,7 +1349,7 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
* pools/users, we can't allow mapping in interrupt context
* because it can corrupt another users mappings.
*/
- WARN_ON_ONCE(in_interrupt());
+ BUG_ON(in_interrupt());

/* From now on, migration cannot move the object */
pin_tag(handle);