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| author |   Yushan Zhou <katrinzhou@tencent.com> | 2022-06-30 16:25:12 +0800 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-07-01 10:36:36 +0200 |
| commit | 72b5d5aef246a0387cefa23121dd90901c7a691a (patch) | |
| tree | 9bffd0b9f249efd1ad75b96c367d1fa878aa4336 | |
| parent | firmware: Hold a reference for of_find_compatible_node() (diff) | |
| download | linux-dev-72b5d5aef246a0387cefa23121dd90901c7a691a.tar.xz linux-dev-72b5d5aef246a0387cefa23121dd90901c7a691a.zip | |
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>
| -rw-r--r-- | fs/kernfs/dir.c | 7 |
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); |