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authorJan Kara <jack@suse.cz>2016-12-21 11:50:39 +0100
committerJan Kara <jack@suse.cz>2017-04-10 17:37:35 +0200
commite7253760587e8523fe1e8ede092a620f1403f2e8 (patch)
tree7bcf5c7a849efedfb497da81e044bbe958d88454 /fs/notify/inotify
parent08991e83b7286635167bab40927665a90fb00d81 (diff)
inotify: Do not drop mark reference under idr_lock
Dropping mark reference can result in mark being freed. Although it should not happen in inotify_remove_from_idr() since caller should hold another reference, just don't risk lock up just after WARN_ON unnecessarily. Also fold do_inotify_remove_from_idr() into the single callsite as that function really is just two lines of real code. Reviewed-by: Miklos Szeredi <mszeredi@redhat.com> Reviewed-by: Amir Goldstein <amir73il@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz>
Diffstat (limited to 'fs/notify/inotify')
-rw-r--r--fs/notify/inotify/inotify_user.c24
1 files changed, 6 insertions, 18 deletions
diff --git a/fs/notify/inotify/inotify_user.c b/fs/notify/inotify/inotify_user.c
index b82a507a5367..f9113e57ef33 100644
--- a/fs/notify/inotify/inotify_user.c
+++ b/fs/notify/inotify/inotify_user.c
@@ -395,21 +395,6 @@ static struct inotify_inode_mark *inotify_idr_find(struct fsnotify_group *group,
return i_mark;
}
-static void do_inotify_remove_from_idr(struct fsnotify_group *group,
- struct inotify_inode_mark *i_mark)
-{
- struct idr *idr = &group->inotify_data.idr;
- spinlock_t *idr_lock = &group->inotify_data.idr_lock;
- int wd = i_mark->wd;
-
- assert_spin_locked(idr_lock);
-
- idr_remove(idr, wd);
-
- /* removed from the idr, drop that ref */
- fsnotify_put_mark(&i_mark->fsn_mark);
-}
-
/*
* Remove the mark from the idr (if present) and drop the reference
* on the mark because it was in the idr.
@@ -417,6 +402,7 @@ static void do_inotify_remove_from_idr(struct fsnotify_group *group,
static void inotify_remove_from_idr(struct fsnotify_group *group,
struct inotify_inode_mark *i_mark)
{
+ struct idr *idr = &group->inotify_data.idr;
spinlock_t *idr_lock = &group->inotify_data.idr_lock;
struct inotify_inode_mark *found_i_mark = NULL;
int wd;
@@ -468,13 +454,15 @@ static void inotify_remove_from_idr(struct fsnotify_group *group,
BUG();
}
- do_inotify_remove_from_idr(group, i_mark);
+ idr_remove(idr, wd);
+ /* Removed from the idr, drop that ref. */
+ fsnotify_put_mark(&i_mark->fsn_mark);
out:
+ i_mark->wd = -1;
+ spin_unlock(idr_lock);
/* match the ref taken by inotify_idr_find_locked() */
if (found_i_mark)
fsnotify_put_mark(&found_i_mark->fsn_mark);
- i_mark->wd = -1;
- spin_unlock(idr_lock);
}
/*