From nobody Tue Apr 28 10:34:18 2026 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 5045DC433F5 for ; Wed, 1 Jun 2022 11:55:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348514AbiFALz0 (ORCPT ); Wed, 1 Jun 2022 07:55:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37372 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233840AbiFALzV (ORCPT ); Wed, 1 Jun 2022 07:55:21 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 135D76B7C0 for ; Wed, 1 Jun 2022 04:55:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1654084519; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=A1XdIemq8frjYfv4a28xhmhvY/SFwVpocirLnr3lxtY=; b=cKkjtT7ASb9L5OQE1eqFNtozHBzeXYLPiSycPsBeFJM6Ai3KYghEHQBmAD/UuAhQSCcEby DDPwXzLfzI0bCqPNt6wYo5c6TLU8+638OBUNgWT3M0OMo1POYMV6X9Gs87E+2d3WxWLt3c fISFhpsL0Jnl5vvbUhQkiyJxQVfrgfM= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-644-AwrvSifIOhi-RiCzV8sH6w-1; Wed, 01 Jun 2022 07:55:13 -0400 X-MC-Unique: AwrvSifIOhi-RiCzV8sH6w-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 481E22949BA3; Wed, 1 Jun 2022 11:55:09 +0000 (UTC) Received: from warthog.procyon.org.uk (unknown [10.33.36.8]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8A37CC23DBF; Wed, 1 Jun 2022 11:55:08 +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] afs: Fix dynamic root getattr From: David Howells To: marc.dionne@auristor.com Cc: linux-afs@lists.infradead.org, dhowells@redhat.com, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 01 Jun 2022 12:55:07 +0100 Message-ID: <165408450783.1031787.7941404776393751186.stgit@warthog.procyon.org.uk> User-Agent: StGit/1.4 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.85 on 10.11.54.8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The recent patch to make afs_getattr consult the server didn't account for the pseudo-inodes employed by the dynamic root-type afs superblock not having a volume or a server to access, and thus an oops occurs if such a directory is stat'd. Fix this by checking to see if the vnode->volume pointer actually points anywhere before following it in afs_getattr(). This can be tested by stat'ing a directory in /afs. It may be sufficient just to do "ls /afs" and the oops looks something like: BUG: kernel NULL pointer dereference, address: 0000000000000020 ... RIP: 0010:afs_getattr+0x8b/0x14b ... Call Trace: vfs_statx+0x79/0xf5 vfs_fstatat+0x49/0x62 Fixes: 2aeb8c86d499 ("afs: Fix afs_getattr() to refetch file status if call= back break occurred") Reported-by: Marc Dionne Signed-off-by: David Howells cc: linux-afs@lists.infradead.org Reviewed-by: Marc Dionne Tested-by: Marc Dionne --- fs/afs/inode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/afs/inode.c b/fs/afs/inode.c index 30b066299d39..33ecbfea0199 100644 --- a/fs/afs/inode.c +++ b/fs/afs/inode.c @@ -745,7 +745,8 @@ int afs_getattr(struct user_namespace *mnt_userns, cons= t struct path *path, =20 _enter("{ ino=3D%lu v=3D%u }", inode->i_ino, inode->i_generation); =20 - if (!(query_flags & AT_STATX_DONT_SYNC) && + if (vnode->volume && + !(query_flags & AT_STATX_DONT_SYNC) && !test_bit(AFS_VNODE_CB_PROMISED, &vnode->flags)) { key =3D afs_request_key(vnode->volume->cell); if (IS_ERR(key))