fuse: release pipe buf after last use

commit 473441720c upstream.

Checking buf->flags should be done before the pipe_buf_release() is called
on the pipe buffer, since releasing the buffer might modify the flags.

This is exactly what page_cache_pipe_buf_release() does, and which results
in the same VM_BUG_ON_PAGE(PageLRU(page)) that the original patch was
trying to fix.

Reported-by: Justin Forbes <jmforbes@linuxtx.org>
Fixes: 712a951025 ("fuse: fix page stealing")
Cc: <stable@vger.kernel.org> # v2.6.35
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Miklos Szeredi 2021-11-25 14:05:18 +01:00 committed by Greg Kroah-Hartman
parent eff32973ec
commit 54f682cd48

View file

@ -839,17 +839,17 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)
goto out_put_old;
}
get_page(newpage);
if (!(buf->flags & PIPE_BUF_FLAG_LRU))
lru_cache_add_file(newpage);
/*
* Release while we have extra ref on stolen page. Otherwise
* anon_pipe_buf_release() might think the page can be reused.
*/
pipe_buf_release(cs->pipe, buf);
get_page(newpage);
if (!(buf->flags & PIPE_BUF_FLAG_LRU))
lru_cache_add_file(newpage);
err = 0;
spin_lock(&cs->req->waitq.lock);
if (test_bit(FR_ABORTED, &cs->req->flags))