From: Yushan Zhou <katrinzhou@tencent.com> mainline inclusion from mainline-v6.0-rc1 commit 72b5d5aef246a0387cefa23121dd90901c7a691a category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/8346 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- When lockdep is enabled, lockdep_assert_held_write would cause potential NULL pointer dereference. Fix the following smatch warnings: fs/kernfs/dir.c:1353 __kernfs_remove() warn: variable dereferenced before check 'kn' (see line 1346) Fixes: 393c3714081a ("kernfs: switch global kernfs_rwsem lock to per-fs lock") Signed-off-by: Yushan Zhou <katrinzhou@tencent.com> Link: https://lore.kernel.org/r/20220630082512.3482581-1-zys.zljxml@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/kernfs/dir.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c index 37dbd6a7b34c..328f88cf653f 100644 --- a/fs/kernfs/dir.c +++ b/fs/kernfs/dir.c @@ -1347,14 +1347,17 @@ static void __kernfs_remove(struct kernfs_node *kn) { struct kernfs_node *pos; + /* Short-circuit if non-root @kn has already finished removal. */ + if (!kn) + return; + lockdep_assert_held_write(&kernfs_root(kn)->kernfs_rwsem); /* - * Short-circuit if non-root @kn has already finished removal. * This is for kernfs_remove_self() which plays with active ref * after removal. */ - if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb))) + if (kn->parent && RB_EMPTY_NODE(&kn->rb)) return; pr_debug("kernfs %s: removing\n", kn->name); -- 2.39.2