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 X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AEF25C43387 for ; Thu, 17 Jan 2019 15:27:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7DFD920652 for ; Thu, 17 Jan 2019 15:27:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728440AbfAQP1x (ORCPT ); Thu, 17 Jan 2019 10:27:53 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52502 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726913AbfAQP1w (ORCPT ); Thu, 17 Jan 2019 10:27:52 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 9682D935C9; Thu, 17 Jan 2019 15:27:52 +0000 (UTC) Received: from warthog.procyon.org.uk (ovpn-120-128.rdu2.redhat.com [10.10.120.128]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8886D10A48D4; Thu, 17 Jan 2019 15:27:51 +0000 (UTC) Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 3/6] afs: Don't set vnode->cb_s_break in afs_validate() From: David Howells To: torvalds@linux-foundation.org Cc: Marc Dionne , dhowells@redhat.com, linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org Date: Thu, 17 Jan 2019 15:27:50 +0000 Message-ID: <154773887076.24105.174798845449873807.stgit@warthog.procyon.org.uk> In-Reply-To: <154773884927.24105.2730570814701376379.stgit@warthog.procyon.org.uk> References: <154773884927.24105.2730570814701376379.stgit@warthog.procyon.org.uk> User-Agent: StGit/unknown-version MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 17 Jan 2019 15:27:52 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marc Dionne A cb_interest record is not necessarily attached to the vnode on entry to afs_validate(), which can cause an oops when we try to bring the vnode's cb_s_break up to date in the default case (ie. no current callback promise and the vnode has not been deleted). Fix this by simply removing the line, as vnode->cb_s_break will be set when needed by afs_register_server_cb_interest() when we next get a callback promise from RPC call. The oops looks something like: BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 ... RIP: 0010:afs_validate+0x66/0x250 [kafs] ... Call Trace: afs_d_revalidate+0x8d/0x340 [kafs] ? __d_lookup+0x61/0x150 lookup_dcache+0x44/0x70 ? lookup_dcache+0x44/0x70 __lookup_hash+0x24/0xa0 do_unlinkat+0x11d/0x2c0 __x64_sys_unlink+0x23/0x30 do_syscall_64+0x4d/0xf0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fixes: ae3b7361dc0e ("afs: Fix validation/callback interaction") Signed-off-by: Marc Dionne Signed-off-by: David Howells --- fs/afs/inode.c | 1 - 1 file changed, 1 deletion(-) diff --git a/fs/afs/inode.c b/fs/afs/inode.c index 6b17d3620414..211343831c30 100644 --- a/fs/afs/inode.c +++ b/fs/afs/inode.c @@ -414,7 +414,6 @@ int afs_validate(struct afs_vnode *vnode, struct key *key) } else if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) { valid = true; } else { - vnode->cb_s_break = vnode->cb_interest->server->cb_s_break; vnode->cb_v_break = vnode->volume->cb_v_break; valid = false; }