From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 87A873AEB5C; Sat, 30 May 2026 17:54:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780163701; cv=none; b=dgaWey7U+idIdO5vtXLJ6tTDViPiEFYhKB15ZKGJcW4DVRxwX/I4RaT9KCtHOvxyYPTPF9gLd/GYs+AakdvKfTLUgBuXf3Vw8MB/u5Ur54yTLHfzs8/rwNknSUf00E9IK5U8YSOS4IGmricZGb8JNO/p01ie6W5SXKbBKnKtyh0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780163701; c=relaxed/simple; bh=AgmkPMAfceJYRED8GEHKdE8x4QAY3hsaC4rzeUKDAaU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PW/KwcFSFD9ec14WEBlv3zSmVIJOgTi8Q5PSxB31+qnBqPQSziocJ0N6BFYAb38RwVAFRwkDnK+HZqQ/3R6QLMTPTPjcy5g9sKma/IVgc3vaY+0LfplzlDLNvcDIjQzVtCMsg5Hx+6wV/lpUJKZRpw0lDr9S62JBZ31XBBJ/i48= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=feWWVUVf; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="feWWVUVf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8EF3B1F00893; Sat, 30 May 2026 17:54:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780163698; bh=pvC6+wMVW5AQ0BR6/qbYQEGloWGuQgJnbAsC2wTOxGc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=feWWVUVfkYKVx+mz50lDejUiUPI4k12p1dBSGaOJzWjkBOZMRz5XLu1sSGZrYMIT0 KnMO1AIaXbSiHN1KUnsyYjK1bV4LeOnIe0E+y4PqcmDp6GBvnL+qwfXVQNHYjNrHop JtWIKnmKTgGzzBz1OevUPB0J7sbrXZ8u4BkfzyEc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christoph Hellwig , Chaitanya Kulkarni , Keith Busch Subject: [PATCH 5.15 336/776] nvmet: avoid recursive nvmet-wq flush in nvmet_ctrl_free Date: Sat, 30 May 2026 18:00:50 +0200 Message-ID: <20260530160249.255922506@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260530160240.228940103@linuxfoundation.org> References: <20260530160240.228940103@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chaitanya Kulkarni commit aade8abd8b868b6ffa9697aadaea28ec7f65bee6 upstream. nvmet_tcp_release_queue_work() runs on nvmet-wq and can drop the final controller reference through nvmet_cq_put(). If that triggers nvmet_ctrl_free(), the teardown path flushes ctrl->async_event_work on the same nvmet-wq. Call chain: nvmet_tcp_schedule_release_queue() kref_put(&queue->kref, nvmet_tcp_release_queue) nvmet_tcp_release_queue() queue_work(nvmet_wq, &queue->release_work) <--- nvmet_wq process_one_work() nvmet_tcp_release_queue_work() nvmet_cq_put(&queue->nvme_cq) nvmet_cq_destroy() nvmet_ctrl_put(cq->ctrl) nvmet_ctrl_free() flush_work(&ctrl->async_event_work) <--- nvmet_wq Previously Scheduled by :- nvmet_add_async_event queue_work(nvmet_wq, &ctrl->async_event_work); This trips lockdep with a possible recursive locking warning. [ 5223.015876] run blktests nvme/003 at 2026-04-07 20:53:55 [ 5223.061801] loop0: detected capacity change from 0 to 2097152 [ 5223.072206] nvmet: adding nsid 1 to subsystem blktests-subsystem-1 [ 5223.088368] nvmet_tcp: enabling port 0 (127.0.0.1:4420) [ 5223.126086] nvmet: Created discovery controller 1 for subsystem nqn.2014-08.org.nvmexpress.discovery for NQN nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349. [ 5223.128453] nvme nvme1: new ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery", addr 127.0.0.1:4420, hostnqn: nqn.2014-08.org.nvmexpress:uuid:0f01fb42-9f7f-4856-b0b3-51e60b8de349 [ 5233.199447] nvme nvme1: Removing ctrl: NQN "nqn.2014-08.org.nvmexpress.discovery" [ 5233.227718] ============================================ [ 5233.231283] WARNING: possible recursive locking detected [ 5233.234696] 7.0.0-rc3nvme+ #20 Tainted: G O N [ 5233.238434] -------------------------------------------- [ 5233.241852] kworker/u192:6/2413 is trying to acquire lock: [ 5233.245429] ffff888111632548 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x26/0x90 [ 5233.251438] but task is already holding lock: [ 5233.255254] ffff888111632548 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x5cc/0x6e0 [ 5233.261125] other info that might help us debug this: [ 5233.265333] Possible unsafe locking scenario: [ 5233.269217] CPU0 [ 5233.270795] ---- [ 5233.272436] lock((wq_completion)nvmet-wq); [ 5233.275241] lock((wq_completion)nvmet-wq); [ 5233.278020] *** DEADLOCK *** [ 5233.281793] May be due to missing lock nesting notation [ 5233.286195] 3 locks held by kworker/u192:6/2413: [ 5233.289192] #0: ffff888111632548 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x5cc/0x6e0 [ 5233.294569] #1: ffffc9000e2a7e40 ((work_completion)(&queue->release_work)){+.+.}-{0:0}, at: process_one_work+0x1c5/0x6e0 [ 5233.300128] #2: ffffffff82d7dc40 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x62/0x530 [ 5233.304290] stack backtrace: [ 5233.306520] CPU: 4 UID: 0 PID: 2413 Comm: kworker/u192:6 Tainted: G O N 7.0.0-rc3nvme+ #20 PREEMPT(full) [ 5233.306524] Tainted: [O]=OOT_MODULE, [N]=TEST [ 5233.306525] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 [ 5233.306527] Workqueue: nvmet-wq nvmet_tcp_release_queue_work [nvmet_tcp] [ 5233.306532] Call Trace: [ 5233.306534] [ 5233.306536] dump_stack_lvl+0x73/0xb0 [ 5233.306552] print_deadlock_bug+0x225/0x2f0 [ 5233.306556] __lock_acquire+0x13f0/0x2290 [ 5233.306563] lock_acquire+0xd0/0x300 [ 5233.306565] ? touch_wq_lockdep_map+0x26/0x90 [ 5233.306571] ? __flush_work+0x20b/0x530 [ 5233.306573] ? touch_wq_lockdep_map+0x26/0x90 [ 5233.306577] touch_wq_lockdep_map+0x3b/0x90 [ 5233.306580] ? touch_wq_lockdep_map+0x26/0x90 [ 5233.306583] ? __flush_work+0x20b/0x530 [ 5233.306585] __flush_work+0x268/0x530 [ 5233.306588] ? __pfx_wq_barrier_func+0x10/0x10 [ 5233.306594] ? xen_error_entry+0x30/0x60 [ 5233.306600] nvmet_ctrl_free+0x140/0x310 [nvmet] [ 5233.306617] nvmet_cq_put+0x74/0x90 [nvmet] [ 5233.306629] nvmet_tcp_release_queue_work+0x19f/0x360 [nvmet_tcp] [ 5233.306634] process_one_work+0x206/0x6e0 [ 5233.306640] worker_thread+0x184/0x320 [ 5233.306643] ? __pfx_worker_thread+0x10/0x10 [ 5233.306646] kthread+0xf1/0x130 [ 5233.306648] ? __pfx_kthread+0x10/0x10 [ 5233.306651] ret_from_fork+0x355/0x450 [ 5233.306653] ? __pfx_kthread+0x10/0x10 [ 5233.306656] ret_from_fork_asm+0x1a/0x30 [ 5233.306664] There is also no need to flush async_event_work from controller teardown. The admin queue teardown already fails outstanding AER requests before the final controller put :- nvmet_sq_destroy(admin sq) nvmet_async_events_failall(ctrl) The controller has already been removed from the subsystem list before nvmet_ctrl_free() quiesces outstanding work. Replace flush_work() with cancel_work_sync() so a pending async_event_work item is canceled and a running instance is waited on without recursing into the same workqueue. Fixes: 06406d81a2d7 ("nvmet: cancel fatal error and flush async work before free controller") Cc: stable@vger.kernel.org Reviewed-by: Christoph Hellwig Signed-off-by: Chaitanya Kulkarni Signed-off-by: Keith Busch Signed-off-by: Greg Kroah-Hartman --- drivers/nvme/target/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/nvme/target/core.c +++ b/drivers/nvme/target/core.c @@ -1471,7 +1471,7 @@ static void nvmet_ctrl_free(struct kref nvmet_stop_keep_alive_timer(ctrl); - flush_work(&ctrl->async_event_work); + cancel_work_sync(&ctrl->async_event_work); cancel_work_sync(&ctrl->fatal_err_work); ida_simple_remove(&cntlid_ida, ctrl->cntlid);