[074/118] zswap: potential NULL dereference on error in init_zswap()

Commit Message

Andrew Morton Jan. 31, 2020, 6:15 a.m. UTC

From: Dan Carpenter <[e-mail]>
Subject: zswap: potential NULL dereference on error in init_zswap()

The "pool" pointer can be NULL at the end of the init_zswap().  (We would
allocate a new pool later in that situation.) So in the error handling
then we need to make sure pool is a valid pointer before calling
"zswap_pool_destroy(pool);" because that function dereferences the
argument.

Link: http://lkml.kernel.org/r/[e-mail]
Fixes: 93d4dfa9fbd0 ("mm/zswap.c: add allocation hysteresis if pool limit is hit")
Signed-off-by: Dan Carpenter <[e-mail]>
Cc: Vitaly Wool <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/zswap.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Patch

--- a/mm/zswap.c~zswap-potential-null-dereference-on-error-in-init_zswap
+++ a/mm/zswap.c
@@ -1359,7 +1359,8 @@  static int __init init_zswap(void)
 	return 0;
 
 fallback_fail:
-	zswap_pool_destroy(pool);
+	if (pool)
+		zswap_pool_destroy(pool);
 hp_fail:
 	cpuhp_remove_state(CPUHP_MM_ZSWP_MEM_PREPARE);
 dstmem_fail: