From: Eiichi Tsukata devel@etsukata.com
stable inclusion from linux-4.19.142 commit c90652abae15465210207418ac8c1ecb230e3b1e
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[ Upstream commit 96cf2a2c75567ff56195fe3126d497a2e7e4379f ]
If xfs_sysfs_init is called with parent_kobj == NULL, UBSAN shows the following warning:
UBSAN: null-ptr-deref in ./fs/xfs/xfs_sysfs.h:37:23 member access within null pointer of type 'struct xfs_kobj' Call Trace: dump_stack+0x10e/0x195 ubsan_type_mismatch_common+0x241/0x280 __ubsan_handle_type_mismatch_v1+0x32/0x40 init_xfs_fs+0x12b/0x28f do_one_initcall+0xdd/0x1d0 do_initcall_level+0x151/0x1b6 do_initcalls+0x50/0x8f do_basic_setup+0x29/0x2b kernel_init_freeable+0x19f/0x20b kernel_init+0x11/0x1e0 ret_from_fork+0x22/0x30
Fix it by checking parent_kobj before the code accesses its member.
Signed-off-by: Eiichi Tsukata devel@etsukata.com Reviewed-by: Darrick J. Wong darrick.wong@oracle.com [darrick: minor whitespace edits] Signed-off-by: Darrick J. Wong darrick.wong@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- fs/xfs/xfs_sysfs.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/xfs/xfs_sysfs.h b/fs/xfs/xfs_sysfs.h index e9f810fc6731..43585850f154 100644 --- a/fs/xfs/xfs_sysfs.h +++ b/fs/xfs/xfs_sysfs.h @@ -32,9 +32,11 @@ xfs_sysfs_init( struct xfs_kobj *parent_kobj, const char *name) { + struct kobject *parent; + + parent = parent_kobj ? &parent_kobj->kobject : NULL; init_completion(&kobj->complete); - return kobject_init_and_add(&kobj->kobject, ktype, - &parent_kobj->kobject, "%s", name); + return kobject_init_and_add(&kobj->kobject, ktype, parent, "%s", name); }
static inline void