From: Pavel Skripkin <paskripkin@xxxxxxxxx>
Subject: nilfs2: fix memory leak in nilfs_sysfs_delete_device_group
My local syzbot instance hit memory leak in nilfs2. The problem was in
missing kobject_put() in nilfs_sysfs_delete_device_group().
kobject_del() does not call kobject_cleanup() for passed kobject and it
leads to leaking duped kobject name if kobject_put() was not called.
Fail log:
BUG: memory leak
unreferenced object 0xffff8880596171e0 (size 8):
comm "syz-executor379", pid 8381, jiffies 4294980258 (age 21.100s)
hex dump (first 8 bytes):
6c 6f 6f 70 30 00 00 00 loop0...
backtrace:
[<ffffffff81a2c656>] kstrdup+0x36/0x70 mm/util.c:60
[<ffffffff81a2c6e3>] kstrdup_const+0x53/0x80 mm/util.c:83
[<ffffffff83ccc698>] kvasprintf_const+0x108/0x190 lib/kasprintf.c:48
[<ffffffff83e99926>] kobject_set_name_vargs+0x56/0x150 lib/kobject.c:289
[<ffffffff83e99fd9>] kobject_add_varg lib/kobject.c:384 [inline]
[<ffffffff83e99fd9>] kobject_init_and_add+0xc9/0x160 lib/kobject.c:473
[<ffffffff8304e840>] nilfs_sysfs_create_device_group+0x150/0x800 fs/nilfs2/sysfs.c:999
[<ffffffff830159f6>] init_nilfs+0xe26/0x12b0 fs/nilfs2/the_nilfs.c:637
Link: https://lkml.kernel.org/r/20210612140559.20022-1-paskripkin@xxxxxxxxx
Fixes: da7141fb78db ("nilfs2: add /sys/fs/nilfs2/<device> group")
Signed-off-by: Pavel Skripkin <paskripkin@xxxxxxxxx>
Acked-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Cc: Michael L. Semon <mlsemon35@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/nilfs2/sysfs.c | 1 +
1 file changed, 1 insertion(+)
--- a/fs/nilfs2/sysfs.c~nilfs2-fix-memory-leak-in-nilfs_sysfs_delete_device_group
+++ a/fs/nilfs2/sysfs.c
@@ -1053,6 +1053,7 @@ void nilfs_sysfs_delete_device_group(str
nilfs_sysfs_delete_superblock_group(nilfs);
nilfs_sysfs_delete_segctor_group(nilfs);
kobject_del(&nilfs->ns_dev_kobj);
+ kobject_put(&nilfs->ns_dev_kobj);
kfree(nilfs->ns_dev_subgroups);
}
_
