On Tue, Jun 29, 2021 at 10:11 PM Gabriel Krisman Bertazi
[off-list ref] wrote:
Some events, like the overflow event, are not mergeable, so they are not
hashed. But, when failing inside fsnotify_add_event for lack of space,
fsnotify_add_event() still calls the insert hook, which adds the
overflow event to the merge list. Add a check to prevent any kind of
unmergeable event to be inserted in the hashtable.
Fixes: 94e00d28a680 ("fsnotify: use hash table for faster events merge")
Signed-off-by: Gabriel Krisman Bertazi <redacted>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
quoted hunk ↗ jump to hunk
---
Changes since v2:
- Do check for hashed events inside the insert hook (Amir)
---
fs/notify/fanotify/fanotify.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 057abd2cf887..310246f8d3f1 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -702,6 +702,9 @@ static void fanotify_insert_event(struct fsnotify_group *group,
assert_spin_locked(&group->notification_lock);
+ if (!fanotify_is_hashed_event(event->mask))
+ return;
+
pr_debug("%s: group=%p event=%p bucket=%u\n", __func__,
group, event, bucket);
@@ -779,8 +782,7 @@ static int fanotify_handle_event(struct fsnotify_group *group, u32 mask,
fsn_event = &event->fse;
ret = fsnotify_add_event(group, fsn_event, fanotify_merge,
- fanotify_is_hashed_event(mask) ?
- fanotify_insert_event : NULL);
+ fanotify_insert_event);
if (ret) {
/* Permission events shouldn't be merged */
BUG_ON(ret == 1 && mask & FANOTIFY_PERM_EVENTS);
--2.32.0