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 53AF92FC010 for ; Mon, 13 Oct 2025 09:12:18 +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=1760346738; cv=none; b=nRp2X9Y97vskgp3D0vKQf7XYjw7VyhDQwf7z0MvGPQY+5UAecJ2kkFhMqctAVBPP73ruILyelGr8F6NgkzvNh53bHTmhAsKQbU7XvjqQWtp8L6HYN+EaDSi2QpYTstkASy/ge+w9slua+aqkxPdFZRQ/KS7mkXWpT+0DmUGBoh0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760346738; c=relaxed/simple; bh=XCAEnSwTu5V9vlAV9jkG3wA4w/uyYkCcJ03tuLV0J3o=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=WGd0ZgnuJtxlAY3WzIqJTkzlsLyeNleAAYtOVip9vstg+8YT5sT9SWS5C5AiFYpgFbH3n0GMbGGn2qjB5HwPIJdgllENSMMAtHpG4PQAPqHEnX/d5v1AIcK81XdqFxn+aJkQET49zTbeauscRG8m33cg9g9CsXRdXDmTCqSYbPE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=oRFM3s9w; 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="oRFM3s9w" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B1BC5C4CEE7; Mon, 13 Oct 2025 09:12:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1760346738; bh=XCAEnSwTu5V9vlAV9jkG3wA4w/uyYkCcJ03tuLV0J3o=; h=Subject:To:Cc:From:Date:From; b=oRFM3s9w5rK577Kw1a5/jrCOyVJrqV8vLk1Rm8Xd+YuvdCtLYTDs3JKH5ItJitGh1 iXnSm3MmZH/T1BGJ6Wni/QL0lSze/9TpFF33ImK43hskuu5/wi0FWf/nWfxRzCnYcl pnFNOAbS+97tpUfncUfZgRccmTcirYBB2aT8UaZM= Subject: FAILED: patch "[PATCH] dm: fix NULL pointer dereference in __dm_suspend()" failed to apply to 5.15-stable tree To: zhengqixing@huawei.com,mpatocka@redhat.com Cc: From: Date: Mon, 13 Oct 2025 11:12:15 +0200 Message-ID: <2025101315-graveness-treason-be2b@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 8d33a030c566e1f105cd5bf27f37940b6367f3be # git commit -s git send-email --to '' --in-reply-to '2025101315-graveness-treason-be2b@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 8d33a030c566e1f105cd5bf27f37940b6367f3be Mon Sep 17 00:00:00 2001 From: Zheng Qixing Date: Tue, 26 Aug 2025 15:42:04 +0800 Subject: [PATCH] dm: fix NULL pointer dereference in __dm_suspend() There is a race condition between dm device suspend and table load that can lead to null pointer dereference. The issue occurs when suspend is invoked before table load completes: BUG: kernel NULL pointer dereference, address: 0000000000000054 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 6 PID: 6798 Comm: dmsetup Not tainted 6.6.0-g7e52f5f0ca9b #62 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:blk_mq_wait_quiesce_done+0x0/0x50 Call Trace: blk_mq_quiesce_queue+0x2c/0x50 dm_stop_queue+0xd/0x20 __dm_suspend+0x130/0x330 dm_suspend+0x11a/0x180 dev_suspend+0x27e/0x560 ctl_ioctl+0x4cf/0x850 dm_ctl_ioctl+0xd/0x20 vfs_ioctl+0x1d/0x50 __se_sys_ioctl+0x9b/0xc0 __x64_sys_ioctl+0x19/0x30 x64_sys_call+0x2c4a/0x4620 do_syscall_64+0x9e/0x1b0 The issue can be triggered as below: T1 T2 dm_suspend table_load __dm_suspend dm_setup_md_queue dm_mq_init_request_queue blk_mq_init_allocated_queue => q->mq_ops = set->ops; (1) dm_stop_queue / dm_wait_for_completion => q->tag_set NULL pointer! (2) => q->tag_set = set; (3) Fix this by checking if a valid table (map) exists before performing request-based suspend and waiting for target I/O. When map is NULL, skip these table-dependent suspend steps. Even when map is NULL, no I/O can reach any target because there is no table loaded; I/O submitted in this state will fail early in the DM layer. Skipping the table-dependent suspend logic in this case is safe and avoids NULL pointer dereferences. Fixes: c4576aed8d85 ("dm: fix request-based dm's use of dm_wait_for_completion") Cc: stable@vger.kernel.org Signed-off-by: Zheng Qixing Signed-off-by: Mikulas Patocka diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 7222f20c1a83..66dd5f6ce778 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -2908,7 +2908,7 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, { bool do_lockfs = suspend_flags & DM_SUSPEND_LOCKFS_FLAG; bool noflush = suspend_flags & DM_SUSPEND_NOFLUSH_FLAG; - int r; + int r = 0; lockdep_assert_held(&md->suspend_lock); @@ -2960,7 +2960,7 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, * Stop md->queue before flushing md->wq in case request-based * dm defers requests to md->wq from md->queue. */ - if (dm_request_based(md)) { + if (map && dm_request_based(md)) { dm_stop_queue(md->queue); set_bit(DMF_QUEUE_STOPPED, &md->flags); } @@ -2972,7 +2972,8 @@ static int __dm_suspend(struct mapped_device *md, struct dm_table *map, * We call dm_wait_for_completion to wait for all existing requests * to finish. */ - r = dm_wait_for_completion(md, task_state); + if (map) + r = dm_wait_for_completion(md, task_state); if (!r) set_bit(dmf_suspended_flag, &md->flags);