From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3DB3C433F5 for ; Mon, 29 Nov 2021 18:29:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1379112AbhK2ScZ (ORCPT ); Mon, 29 Nov 2021 13:32:25 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:35070 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352287AbhK2SaX (ORCPT ); Mon, 29 Nov 2021 13:30:23 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id E3A5DB815B1; Mon, 29 Nov 2021 18:27:03 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 24000C53FCD; Mon, 29 Nov 2021 18:27:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1638210422; bh=XMhFXhCx2JdXAbtMICOI0/Qn84NvHuijMCKkJ101IfM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=TmhphBaPXcMHyw4fIkOkNeswXexaz12BlC83PpsR/aG8la6w+sSHwTnVae5+/r5zG fywLn6fSoKusPB6lIYUg9zXF4kE1dCuGHHK54d3naqDEKdWWSLNZzOfkGRUhr8Mj8n MVzAG8C5LboMVWwWgWmIZYPxe56UnOH8ouMeSupw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Justin Forbes , Miklos Szeredi Subject: [PATCH 5.4 83/92] fuse: release pipe buf after last use Date: Mon, 29 Nov 2021 19:18:52 +0100 Message-Id: <20211129181710.167817946@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211129181707.392764191@linuxfoundation.org> References: <20211129181707.392764191@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Miklos Szeredi commit 473441720c8616dfaf4451f9c7ea14f0eb5e5d65 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 Fixes: 712a951025c0 ("fuse: fix page stealing") Cc: # v2.6.35 Signed-off-by: Miklos Szeredi Signed-off-by: Greg Kroah-Hartman --- fs/fuse/dev.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -839,17 +839,17 @@ static int fuse_try_move_page(struct fus 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))