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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 D1777C433EF for ; Sun, 8 Sep 2019 12:54:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ABE4420693 for ; Sun, 8 Sep 2019 12:54:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567947248; bh=33mGaRZWrHhwiqP9nSj/0YhKLqDFGd9MZYXKhyZajIY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=rxSb0okkabGveF4zmwgye6VLtLnUkcmpV9Pft5+Lnz2M7UYzCp/No7ZvNDq6r669v oGUDjc1deTjaBroKEso7O31DHzYBnkk1ITLkrBvqtlOrCkI6wyXK+OBSbWozdve+Fb gk7s9ktJ2N9W5mAktQTU2a2u5ObflyIZ1JnGGMVE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727133AbfIHMyD (ORCPT ); Sun, 8 Sep 2019 08:54:03 -0400 Received: from mail.kernel.org ([198.145.29.99]:45258 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733189AbfIHMwp (ORCPT ); Sun, 8 Sep 2019 08:52:45 -0400 Received: from localhost (unknown [62.28.240.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9E1572190F; Sun, 8 Sep 2019 12:52:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1567947165; bh=33mGaRZWrHhwiqP9nSj/0YhKLqDFGd9MZYXKhyZajIY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Cdzh4pUVZXQsWVhFwZRsJJrrqBqoDZpbSgEowDg87ZEdO3KgZXd/j9x0z4JH0Uhoy lVZ7XqWJ4ZNsqN/pWl9d3EIKvq1R9I08eH+A59Rqw+1VEEi+cssD044LpXTNzJdMY4 4ewV7Nuktxv1Y5KLtmorHML+kjDSaAvYKUJKtxRA= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Marc Dionne , David Howells , Sasha Levin Subject: [PATCH 5.2 85/94] afs: Fix possible oops in afs_lookup trace event Date: Sun, 8 Sep 2019 13:42:21 +0100 Message-Id: <20190908121152.865634230@linuxfoundation.org> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20190908121150.420989666@linuxfoundation.org> References: <20190908121150.420989666@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org [ Upstream commit c4c613ff08d92e72bf64a65ec35a2c3aa1cfcd06 ] The afs_lookup trace event can cause the following: [ 216.576777] BUG: kernel NULL pointer dereference, address: 000000000000023b [ 216.576803] #PF: supervisor read access in kernel mode [ 216.576813] #PF: error_code(0x0000) - not-present page ... [ 216.576913] RIP: 0010:trace_event_raw_event_afs_lookup+0x9e/0x1c0 [kafs] If the inode from afs_do_lookup() is an error other than ENOENT, or if it is ENOENT and afs_try_auto_mntpt() returns an error, the trace event will try to dereference the error pointer as a valid pointer. Use IS_ERR_OR_NULL to only pass a valid pointer for the trace, or NULL. Ideally the trace would include the error value, but for now just avoid the oops. Fixes: 80548b03991f ("afs: Add more tracepoints") Signed-off-by: Marc Dionne Signed-off-by: David Howells Signed-off-by: Sasha Levin --- fs/afs/dir.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/afs/dir.c b/fs/afs/dir.c index 9620f19308f58..9bd5c067d55d1 100644 --- a/fs/afs/dir.c +++ b/fs/afs/dir.c @@ -960,7 +960,8 @@ static struct dentry *afs_lookup(struct inode *dir, struct dentry *dentry, inode ? AFS_FS_I(inode) : NULL); } else { trace_afs_lookup(dvnode, &dentry->d_name, - inode ? AFS_FS_I(inode) : NULL); + IS_ERR_OR_NULL(inode) ? NULL + : AFS_FS_I(inode)); } return d; } -- 2.20.1