From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AFF2A36F431; Tue, 17 Feb 2026 20:41:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771360918; cv=none; b=FeSs3If6f0RpF1/EhE5B9LL4QQSlExNHxXMI5auotFGFsHIsK4STG34TXOAEfGc6v/hzLeBie+PFBbQsx/HmLoa72n9tah8xlIC3BbxZIvj5Qqj5/L8qynDKLfO4dfTiuAbrkhcxuCNZnsE/eHXMInCuOEvH58vPb4ebRyDMbiQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771360918; c=relaxed/simple; bh=q8NNeIZaZFtybRSwGeIlRtuZJ+Tm8O4cyeP+FYPLwNk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=tmMKLZWfGB+Sb9X5EChaIb3skjWUxCvKWQuGsipYGyflZXnIU0N7WmB87OGpAxBY025Tx6YI27Asc03+qtHi7gjRClGmwFFTWBEn356Zji2Lti+eVe93RxZfe24FypzfsnSG0mAU1NrQ6sE2EH6svLTKkNKh6cDIciOoLmug9l4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=01jkR8r6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="01jkR8r6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 20C10C4CEF7; Tue, 17 Feb 2026 20:41:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1771360918; bh=q8NNeIZaZFtybRSwGeIlRtuZJ+Tm8O4cyeP+FYPLwNk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=01jkR8r6YlowMHpNPGEgRo93UkMWWb6eR1WGPoASfAHt8oFISZNWQEAOYaesu1DV4 u231Q31pB3Y6l8O+sV1Fb2LZijI/NFaKX88OHiMqbraNDUYfNY5BpH5Bgfea5RTiw/ 8Im4vYnFEuJEZDQJaJJ6xb634hMg8P8/0IoZ8JjI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Alexander Aring , David Teigland , Bin Lan Subject: [PATCH 5.10 14/24] fs: dlm: fix invalid derefence of sb_lvbptr Date: Tue, 17 Feb 2026 21:31:27 +0100 Message-ID: <20260217200001.258709701@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260217200000.708219618@linuxfoundation.org> References: <20260217200000.708219618@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alexander Aring [ Upstream commit 7175e131ebba47afef47e6ac4d5bab474d1e6e49 ] 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: 00000000deadbeef [ 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: 0000000000000040 [ 102.749360] RDX: 0000000000000040 RSI: 00000000deadbeef RDI: ffff901778b77070 [ 102.749362] RBP: ffff97a58145fd10 R08: ffff901760b67a70 R09: 0000000000000001 [ 102.749364] R10: ffff9017008e2cb8 R11: 0000000000000001 R12: ffff901760b67a70 [ 102.749366] R13: ffff901760b78f00 R14: 0000000000000003 R15: 0000000000000001 [ 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: 0000000000770ef0 [ 102.749376] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 102.749378] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 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 intel_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 virtio_balloon snd_pcm drm_kms_helper virtio_console snd_timer snd drm soundcore syscopyarea i2c_i801 sysfillrect sysimgblt i2c_smbus pcspkr fb_sys_fops lpc_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 [ Adjust context ] Signed-off-by: Bin Lan 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 @@ -3635,7 +3635,7 @@ static void send_args(struct dlm_rsb *r, case DLM_MSG_REQUEST_REPLY: case DLM_MSG_CONVERT_REPLY: case 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;