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    SubjectRe: [patch] updated inotify for 2.6.12-rc3.
    > +static int inotify_ignore(struct inotify_device *dev, s32 wd)
    > +{
    > + struct inotify_watch *watch;
    > + struct inode *inode;
    > +
    > + down(&dev->sem);
    > + watch = idr_find(&dev->idr, wd);
    > + if (unlikely(!watch)) {
    > + up(&dev->sem);
    > + return -EINVAL;
    > + }
    > + get_inotify_watch(watch);
    > + up(&dev->sem);
    > +
    > + inode = watch->inode;
    > + down(&inode->inotify_sem);
    > + down(&dev->sem);
    > + remove_watch(watch, dev);
    > + up(&dev->sem);
    > + up(&inode->inotify_sem);
    > + put_inotify_watch(watch);
    > +
    > + return 0;
    > +}

    So what happens if
    * something is holding inotify_sem right now
    * ten threads call that on the same watch
    * all of them get to down(&inode->inotify_sem); and block there,
    having acquired ten references to the watch
    * after whatever had been holding ->inotify_sem in the first place
    releases it, they will one by one go through the rest of function. And
    drop _20_ references to the watch. 9 of those - after we kfree() the
    watch...
    -
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