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inotify: do not leak inode marks in inotify_add_watch
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>
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@ -463,9 +463,6 @@ static int inotify_update_watch(struct fsnotify_group *group, struct inode *inod
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goto out_err;
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spin_lock(&group->inotify_data.idr_lock);
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/* if entry is added to the idr we keep the reference obtained
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* through fsnotify_mark_add. remember to drop this reference
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* when entry is removed from idr */
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ret = idr_get_new_above(&group->inotify_data.idr, entry,
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++group->inotify_data.last_wd,
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&ientry->wd);
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@ -476,8 +473,13 @@ static int inotify_update_watch(struct fsnotify_group *group, struct inode *inod
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goto out_err;
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}
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atomic_inc(&group->inotify_data.user->inotify_watches);
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/* we put the mark on the idr, take a reference */
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fsnotify_get_mark(entry);
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}
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ret = ientry->wd;
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spin_lock(&entry->lock);
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old_mask = entry->mask;
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@ -508,7 +510,11 @@ static int inotify_update_watch(struct fsnotify_group *group, struct inode *inod
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fsnotify_recalc_group_mask(group);
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}
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return ientry->wd;
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/* this either matches fsnotify_find_mark_entry, or init_mark_entry
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* depending on which path we took... */
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fsnotify_put_mark(entry);
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return ret;
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out_err:
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/* see this isn't supposed to happen, just kill the watch */
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