From 96cf2a2c75567ff56195fe3126d497a2e7e4379f Mon Sep 17 00:00:00 2001 From: Eiichi Tsukata Date: Thu, 6 Aug 2020 15:18:48 -0700 Subject: [PATCH] xfs: Fix UBSAN null-ptr-deref in xfs_sysfs_init 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 Reviewed-by: Darrick J. Wong [darrick: minor whitespace edits] Signed-off-by: Darrick J. Wong --- 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 -- 2.39.5