From nobody Fri Oct 17 08:49:20 2025 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 7FE0EC4332F for ; Wed, 19 Oct 2022 08:42:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230504AbiJSImP (ORCPT ); Wed, 19 Oct 2022 04:42:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55680 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230417AbiJSIkw (ORCPT ); Wed, 19 Oct 2022 04:40:52 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4372C7E31C; Wed, 19 Oct 2022 01:39:15 -0700 (PDT) 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 3F125B822DA; Wed, 19 Oct 2022 08:39:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0297C4314E; Wed, 19 Oct 2022 08:39:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1666168753; bh=4YV9U22rMuVZHOD9Ed04txET9EO0qOS400nx64n0NYI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qAZjiehoG78j4p5Z0inWfLCxUAo4Dss70QcLrpA1trCgjgWWKaFLCk1aZneSgIOpK p8qs7VFnTYSxVGKSbp3lhVfFPcVbDXJpIn/N/i+lTNq3XoTXX5S1tGLX39RIxIWoQx r0DQ2PgxdcUHqSeJzxATTM+bd/S+gCoJeTDePrSI= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Alexander Aring , David Teigland Subject: [PATCH 6.0 043/862] fs: dlm: fix invalid derefence of sb_lvbptr Date: Wed, 19 Oct 2022 10:22:10 +0200 Message-Id: <20221019083251.896817897@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221019083249.951566199@linuxfoundation.org> References: <20221019083249.951566199@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Alexander Aring commit 7175e131ebba47afef47e6ac4d5bab474d1e6e49 upstream. I experience issues when putting a lkbsb on the stack and have sb_lvbptr field to a dangled pointer while not using DLM_LKF_VALBLK. It will crash with the following kernel message, the dangled pointer is here 0xdeadbeef as example: [ 102.749317] BUG: unable to handle page fault for address: 00000000deadbe= ef [ 102.749320] #PF: supervisor read access in kernel mode [ 102.749323] #PF: error_code(0x0000) - not-present page [ 102.749325] PGD 0 P4D 0 [ 102.749332] Oops: 0000 [#1] PREEMPT SMP PTI [ 102.749336] CPU: 0 PID: 1567 Comm: lock_torture_wr Tainted: G W = 5.19.0-rc3+ #1565 [ 102.749343] Hardware name: Red Hat KVM/RHEL-AV, BIOS 1.16.0-2.module+el8= .7.0+15506+033991b0 04/01/2014 [ 102.749344] RIP: 0010:memcpy_erms+0x6/0x10 [ 102.749353] Code: cc cc cc cc eb 1e 0f 1f 00 48 89 f8 48 89 d1 48 c1 e9 = 03 83 e2 07 f3 48 a5 89 d1 f3 a4 c3 66 0f 1f 44 00 00 48 89 f8 48 89 d1 a4 c3 0f 1f 80 00 00 00 00 48 89 f8 48 83 fa 20 72 7e 40 38 fe [ 102.749355] RSP: 0018:ffff97a58145fd08 EFLAGS: 00010202 [ 102.749358] RAX: ffff901778b77070 RBX: 0000000000000000 RCX: 00000000000= 00040 [ 102.749360] RDX: 0000000000000040 RSI: 00000000deadbeef RDI: ffff901778b= 77070 [ 102.749362] RBP: ffff97a58145fd10 R08: ffff901760b67a70 R09: 00000000000= 00001 [ 102.749364] R10: ffff9017008e2cb8 R11: 0000000000000001 R12: ffff901760b= 67a70 [ 102.749366] R13: ffff901760b78f00 R14: 0000000000000003 R15: 00000000000= 00001 [ 102.749368] FS: 0000000000000000(0000) GS:ffff901876e00000(0000) knlGS:= 0000000000000000 [ 102.749372] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 102.749374] CR2: 00000000deadbeef CR3: 000000017c49a004 CR4: 00000000007= 70ef0 [ 102.749376] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 00000000000= 00000 [ 102.749378] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 00000000000= 00400 [ 102.749379] PKRU: 55555554 [ 102.749381] Call Trace: [ 102.749382] [ 102.749383] ? send_args+0xb2/0xd0 [ 102.749389] send_common+0xb7/0xd0 [ 102.749395] _unlock_lock+0x2c/0x90 [ 102.749400] unlock_lock.isra.56+0x62/0xa0 [ 102.749405] dlm_unlock+0x21e/0x330 [ 102.749411] ? lock_torture_stats+0x80/0x80 [dlm_locktorture] [ 102.749416] torture_unlock+0x5a/0x90 [dlm_locktorture] [ 102.749419] ? preempt_count_sub+0xba/0x100 [ 102.749427] lock_torture_writer+0xbd/0x150 [dlm_locktorture] [ 102.786186] kthread+0x10a/0x130 [ 102.786581] ? kthread_complete_and_exit+0x20/0x20 [ 102.787156] ret_from_fork+0x22/0x30 [ 102.787588] [ 102.787855] Modules linked in: dlm_locktorture torture rpcsec_gss_krb5 i= ntel_rapl_msr intel_rapl_common kvm_intel iTCO_wdt iTCO_vendor_support kvm = vmw_vsock_virtio_transport qxl irqbypass vmw_vsock_virtio_transport_common = drm_ttm_helper crc32_pclmul joydev crc32c_intel ttm vsock virtio_scsi virti= o_balloon snd_pcm drm_kms_helper virtio_console snd_timer snd drm soundcore= syscopyarea i2c_i801 sysfillrect sysimgblt i2c_smbus pcspkr fb_sys_fops lp= c_ich serio_raw [ 102.792536] CR2: 00000000deadbeef [ 102.792930] ---[ end trace 0000000000000000 ]--- This patch fixes the issue by checking also on DLM_LKF_VALBLK on exflags is set when copying the lvbptr array instead of if it's just null which fixes for me the issue. I think this patch can fix other dlm users as well, depending how they handle the init, freeing memory handling of sb_lvbptr and don't set DLM_LKF_VALBLK for some dlm_lock() calls. It might a there could be a hidden issue all the time. However with checking on DLM_LKF_VALBLK the user always need to provide a sb_lvbptr non-null value. There might be more intelligent handling between per ls lvblen, DLM_LKF_VALBLK and non-null to report the user the way how DLM API is used is wrong but can be added for later, this will only fix the current behaviour. Cc: stable@vger.kernel.org Signed-off-by: Alexander Aring Signed-off-by: David Teigland Signed-off-by: Greg Kroah-Hartman --- fs/dlm/lock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/dlm/lock.c +++ b/fs/dlm/lock.c @@ -3623,7 +3623,7 @@ static void send_args(struct dlm_rsb *r, case cpu_to_le32(DLM_MSG_REQUEST_REPLY): case cpu_to_le32(DLM_MSG_CONVERT_REPLY): case cpu_to_le32(DLM_MSG_GRANT): - if (!lkb->lkb_lvbptr) + if (!lkb->lkb_lvbptr || !(lkb->lkb_exflags & DLM_LKF_VALBLK)) break; memcpy(ms->m_extra, lkb->lkb_lvbptr, r->res_ls->ls_lvblen); break;