CVE-2026-46040
Description
In the Linux kernel, the following vulnerability has been resolved:
inotify: fix watch count leak when fsnotify_add_inode_mark_locked() fails
When fsnotify_add_inode_mark_locked() fails in inotify_new_watch(),
the error path calls inotify_remove_from_idr() but does not call
dec_inotify_watches() to undo the preceding inc_inotify_watches().
This leaks a watch count, and repeated failures can exhaust the
max_user_watches limit with -ENOSPC even when no watches are active.
Prior to commit 1cce1eea0aff ('inotify: Convert to using per-namespace
limits'), the watch count was incremented after fsnotify_add_mark_locked()
succeeded, so this path was not affected. The conversion moved
inc_inotify_watches() before the mark insertion without adding the
corresponding rollback.
Add the missing dec_inotify_watches() call in the error path.