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authorYushan Zhou <katrinzhou@tencent.com>2022-06-30 11:25:12 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-07-01 11:36:36 +0300
commit72b5d5aef246a0387cefa23121dd90901c7a691a (patch)
tree9bffd0b9f249efd1ad75b96c367d1fa878aa4336 /fs/kernfs
parentc882716b6d411495f221bdd73e9137357c16a3ea (diff)
downloadlinux-72b5d5aef246a0387cefa23121dd90901c7a691a.tar.xz
kernfs: fix potential NULL dereference in __kernfs_remove
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>
Diffstat (limited to 'fs/kernfs')
-rw-r--r--fs/kernfs/dir.c7
1 files changed, 5 insertions, 2 deletions
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 6eca72cfa1f2..1cc88ba6de90 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -1343,14 +1343,17 @@ 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);