From: Nanyong Sun <sunnanyong@xxxxxxxxxx>
[ Upstream commit 5f5dec07aca7067216ed4c1342e464e7307a9197 ]
Patch series "nilfs2: fix incorrect usage of kobject".
This patchset from Nanyong Sun fixes memory leak issues and a NULL
pointer dereference issue caused by incorrect usage of kboject in nilfs2
sysfs implementation.
This patch (of 6):
Reported by syzkaller:
BUG: memory leak
unreferenced object 0xffff888100ca8988 (size 8):
comm "syz-executor.1", pid 1930, jiffies 4294745569 (age 18.052s)
hex dump (first 8 bytes):
6c 6f 6f 70 31 00 ff ff loop1...
backtrace:
kstrdup+0x36/0x70 mm/util.c:60
kstrdup_const+0x35/0x60 mm/util.c:83
kvasprintf_const+0xf1/0x180 lib/kasprintf.c:48
kobject_set_name_vargs+0x56/0x150 lib/kobject.c:289
kobject_add_varg lib/kobject.c:384 [inline]
kobject_init_and_add+0xc9/0x150 lib/kobject.c:473
nilfs_sysfs_create_device_group+0x150/0x7d0 fs/nilfs2/sysfs.c:986
init_nilfs+0xa21/0xea0 fs/nilfs2/the_nilfs.c:637
nilfs_fill_super fs/nilfs2/super.c:1046 [inline]
nilfs_mount+0x7b4/0xe80 fs/nilfs2/super.c:1316
legacy_get_tree+0x105/0x210 fs/fs_context.c:592
vfs_get_tree+0x8e/0x2d0 fs/super.c:1498
do_new_mount fs/namespace.c:2905 [inline]
path_mount+0xf9b/0x1990 fs/namespace.c:3235
do_mount+0xea/0x100 fs/namespace.c:3248
__do_sys_mount fs/namespace.c:3456 [inline]
__se_sys_mount fs/namespace.c:3433 [inline]
__x64_sys_mount+0x14b/0x1f0 fs/namespace.c:3433
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
If kobject_init_and_add return with error, then the cleanup of kobject
is needed because memory may be allocated in kobject_init_and_add
without freeing.
And the place of cleanup_dev_kobject should use kobject_put to free the
memory associated with the kobject. As the section "Kobject removal" of
"Documentation/core-api/kobject.rst" says, kobject_del() just makes the
kobject "invisible", but it is not cleaned up. And no more cleanup will
do after cleanup_dev_kobject, so kobject_put is needed here.
Link: https://lkml.kernel.org/r/1625651306-10829-1-git-send-email-konishi.ryusuke@xxxxxxxxx
Link: https://lkml.kernel.org/r/1625651306-10829-2-git-send-email-konishi.ryusuke@xxxxxxxxx
Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Link: https://lkml.kernel.org/r/20210629022556.3985106-2-sunnanyong@xxxxxxxxxx
Signed-off-by: Nanyong Sun <sunnanyong@xxxxxxxxxx>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
fs/nilfs2/sysfs.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/fs/nilfs2/sysfs.c b/fs/nilfs2/sysfs.c
index 68e8d61e28dd..d2d8ea89937a 100644
--- a/fs/nilfs2/sysfs.c
+++ b/fs/nilfs2/sysfs.c
@@ -986,7 +986,7 @@ int nilfs_sysfs_create_device_group(struct super_block *sb)
err = kobject_init_and_add(&nilfs->ns_dev_kobj, &nilfs_dev_ktype, NULL,
"%s", sb->s_id);
if (err)
- goto free_dev_subgroups;
+ goto cleanup_dev_kobject;
err = nilfs_sysfs_create_mounted_snapshots_group(nilfs);
if (err)
@@ -1023,9 +1023,7 @@ int nilfs_sysfs_create_device_group(struct super_block *sb)
nilfs_sysfs_delete_mounted_snapshots_group(nilfs);
cleanup_dev_kobject:
- kobject_del(&nilfs->ns_dev_kobj);
-
-free_dev_subgroups:
+ kobject_put(&nilfs->ns_dev_kobj);
kfree(nilfs->ns_dev_subgroups);
failed_create_device_group:
--
2.30.2
