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inotify: do not leak inode marks in inotify_add_watch

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inotify_add_watch had a couple of problems.  The biggest being that if
inotify_add_watch was called on the same inode twice (to update or change the
event mask) a refence was taken on the original inode mark by
fsnotify_find_mark_entry but was not being dropped at the end of the
inotify_add_watch call.  Thus if inotify_rm_watch was called although the mark
was removed from the inode, the refcnt wouldn't hit zero and we would leak
memory.

Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Eric Paris <eparis@redhat.com>
This commit is contained in:
Eric Paris
2009-07-07 10:28:23 -04:00
parent 5549f7cdf8
commit 75fe2b2639
1 changed files with 10 additions and 4 deletions
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14
fs/notify/inotify/inotify_user.c
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@@ -463,9 +463,6 @@ retry:
goto out_err; goto out_err;
spin_lock(&group->inotify_data.idr_lock); spin_lock(&group->inotify_data.idr_lock);
/* if entry is added to the idr we keep the reference obtained
* through fsnotify_mark_add. remember to drop this reference
* when entry is removed from idr */
ret = idr_get_new_above(&group->inotify_data.idr, entry, ret = idr_get_new_above(&group->inotify_data.idr, entry,
++group->inotify_data.last_wd, ++group->inotify_data.last_wd,
&ientry->wd); &ientry->wd);
@@ -476,8 +473,13 @@ retry:
goto out_err; goto out_err;
} }
atomic_inc(&group->inotify_data.user->inotify_watches); atomic_inc(&group->inotify_data.user->inotify_watches);
/* we put the mark on the idr, take a reference */
fsnotify_get_mark(entry);
} }
ret = ientry->wd;
spin_lock(&entry->lock); spin_lock(&entry->lock);
old_mask = entry->mask; old_mask = entry->mask;
@@ -508,7 +510,11 @@ retry:
fsnotify_recalc_group_mask(group); fsnotify_recalc_group_mask(group);
} }
return ientry->wd; /* this either matches fsnotify_find_mark_entry, or init_mark_entry
* depending on which path we took... */
fsnotify_put_mark(entry);
return ret;
out_err: out_err:
/* see this isn't supposed to happen, just kill the watch */ /* see this isn't supposed to happen, just kill the watch */