[PATCH v2] mm/slub: fix to return errno if kmalloc() fails

From: Chao Yu
Date: Wed Aug 31 2022 - 10:56:25 EST


From: Chao Yu <chao.yu@xxxxxxxx>

In create_unique_id(), kmalloc(, GFP_KERNEL) can fail due to
out-of-memory, if it fails, return errno correctly rather than
triggering panic via BUG_ON();

kernel BUG at mm/slub.c:5893!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP

Call trace:
sysfs_slab_add+0x258/0x260 mm/slub.c:5973
__kmem_cache_create+0x60/0x118 mm/slub.c:4899
create_cache mm/slab_common.c:229 [inline]
kmem_cache_create_usercopy+0x19c/0x31c mm/slab_common.c:335
kmem_cache_create+0x1c/0x28 mm/slab_common.c:390
f2fs_kmem_cache_create fs/f2fs/f2fs.h:2766 [inline]
f2fs_init_xattr_caches+0x78/0xb4 fs/f2fs/xattr.c:808
f2fs_fill_super+0x1050/0x1e0c fs/f2fs/super.c:4149
mount_bdev+0x1b8/0x210 fs/super.c:1400
f2fs_mount+0x44/0x58 fs/f2fs/super.c:4512
legacy_get_tree+0x30/0x74 fs/fs_context.c:610
vfs_get_tree+0x40/0x140 fs/super.c:1530
do_new_mount+0x1dc/0x4e4 fs/namespace.c:3040
path_mount+0x358/0x914 fs/namespace.c:3370
do_mount fs/namespace.c:3383 [inline]
__do_sys_mount fs/namespace.c:3591 [inline]
__se_sys_mount fs/namespace.c:3568 [inline]
__arm64_sys_mount+0x2f8/0x408 fs/namespace.c:3568

Cc: <stable@xxxxxxxxxx>
Fixes: 81819f0fc8285 ("SLUB core")
Reported-by: syzbot+81684812ea68216e08c5@xxxxxxxxxxxxxxxxxxxxxxxxx
Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Signed-off-by: Chao Yu <chao.yu@xxxxxxxx>
---
v2:
- add more rvb tags and fixes line
mm/slub.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/slub.c b/mm/slub.c
index 862dbd9af4f5..e6f3727b9ad2 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5890,7 +5890,8 @@ static char *create_unique_id(struct kmem_cache *s)
char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
char *p = name;

- BUG_ON(!name);
+ if (!name)
+ return ERR_PTR(-ENOMEM);

*p++ = ':';
/*
@@ -5948,6 +5949,8 @@ static int sysfs_slab_add(struct kmem_cache *s)
* for the symlinks.
*/
name = create_unique_id(s);
+ if (IS_ERR(name))
+ return PTR_ERR(name);
}

s->kobj.kset = kset;
--
2.25.1