+ zswap-potential-null-dereference-on-error-in-init_zswap.patch added to -mm tree

+ zswap-potential-null-dereference-on-error-in-init_zswap.patch added to -mm tree

[akpm]

The patch titled
     Subject: zswap: potential NULL dereference on error in init_zswap()
has been added to the -mm tree.  Its filename is
     zswap-potential-null-dereference-on-error-in-init_zswap.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/zswap-potential-null-dereference-on-error-in-init_zswap.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/zswap-potential-null-dereference-on-error-in-init_zswap.patch

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------------------------------------------------------
From: Dan Carpenter <dan.carpenter@oracle.com>
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/20200114050902.og32fkllkod5ycf5@kili.mountain
Fixes: 93d4dfa9fbd0 ("mm/zswap.c: add allocation hysteresis if pool limit is hit")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

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

--- 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:
_

Patches currently in -mm which might be from dan.carpenter@oracle.com are

zswap-potential-null-dereference-on-error-in-init_zswap.patch