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 7A4CE2D0C94; Tue, 31 Mar 2026 17:00:43 +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=1774976443; cv=none; b=XoIxt7baj511Uo3b6xOTjcC5mJfVz8dNczCwlLESl31YV1ehH6ea1Ae17VIRPWMCKXUO/HqEGqFkqq+cuYzgEATosSCtZGVe52lUA9esap+JBdb6uMQrkkT1xeXhjmtwmGFgEYFo9y44UObEr2a+t5pC6fB6mac6RmA2bjCJEjw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774976443; c=relaxed/simple; bh=I32MGCO7NoUuXjbts+gzS/D5cdCeXvgoTtrUsE51alo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GVGpxaS0pYqOzWGlQpCqkipx20/J6rgn2cbmjsw//gZeFg2CsNJ3shN4mnBPp0UfMsXLKHrE4PpXj2hPW3sKSrO9us8aBSZJHiljHjcZBBbH7QlsHz9kHC+q14ZGUE0sH1Cr3p+p+g6CoNj6d8QBTKEqiPOmDVmRs2IXGdRvqiI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ElfENqIU; 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="ElfENqIU" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E936C19423; Tue, 31 Mar 2026 17:00:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774976443; bh=I32MGCO7NoUuXjbts+gzS/D5cdCeXvgoTtrUsE51alo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ElfENqIUQ3Fn6C476d1iA7WQdfjHFCdyPNMA138Chv8I9szOFFvJGv5heaU1Em28y 4/O45ir3Ey4VqhCE10C1Bgj7Ny1thk3ekvh07PrVyAjS78D1KPNI0p1FNtSsH4Oz0A Kq24IaZ7+G1EnhDF5xapFIDNfeKSAkaGJllIG578= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Christoph Hellwig , Chaitanya Kulkarni , Keith Busch , Sasha Levin Subject: [PATCH 6.18 062/309] nvmet: move async event work off nvmet-wq Date: Tue, 31 Mar 2026 18:19:25 +0200 Message-ID: <20260331161755.770984232@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260331161753.468533260@linuxfoundation.org> References: <20260331161753.468533260@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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chaitanya Kulkarni [ Upstream commit 2922e3507f6d5caa7f1d07f145e186fc6f317a4e ] For target nvmet_ctrl_free() flushes ctrl->async_event_work. If nvmet_ctrl_free() runs on nvmet-wq, the flush re-enters workqueue completion for the same worker:- A. Async event work queued on nvmet-wq (prior to disconnect): nvmet_execute_async_event() queue_work(nvmet_wq, &ctrl->async_event_work) nvmet_add_async_event() queue_work(nvmet_wq, &ctrl->async_event_work) B. Full pre-work chain (RDMA CM path): nvmet_rdma_cm_handler() nvmet_rdma_queue_disconnect() __nvmet_rdma_queue_disconnect() queue_work(nvmet_wq, &queue->release_work) process_one_work() lock((wq_completion)nvmet-wq) <--------- 1st nvmet_rdma_release_queue_work() C. Recursive path (same worker): nvmet_rdma_release_queue_work() nvmet_rdma_free_queue() nvmet_sq_destroy() nvmet_ctrl_put() nvmet_ctrl_free() flush_work(&ctrl->async_event_work) __flush_work() touch_wq_lockdep_map() lock((wq_completion)nvmet-wq) <--------- 2nd Lockdep splat: ============================================ WARNING: possible recursive locking detected 6.19.0-rc3nvme+ #14 Tainted: G N -------------------------------------------- kworker/u192:42/44933 is trying to acquire lock: ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: touch_wq_lockdep_map+0x26/0x90 but task is already holding lock: ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x53e/0x660 3 locks held by kworker/u192:42/44933: #0: ffff888118a00948 ((wq_completion)nvmet-wq){+.+.}-{0:0}, at: process_one_work+0x53e/0x660 #1: ffffc9000e6cbe28 ((work_completion)(&queue->release_work)){+.+.}-{0:0}, at: process_one_work+0x1c5/0x660 #2: ffffffff82d4db60 (rcu_read_lock){....}-{1:3}, at: __flush_work+0x62/0x530 Workqueue: nvmet-wq nvmet_rdma_release_queue_work [nvmet_rdma] Call Trace: __flush_work+0x268/0x530 nvmet_ctrl_free+0x140/0x310 [nvmet] nvmet_cq_put+0x74/0x90 [nvmet] nvmet_rdma_free_queue+0x23/0xe0 [nvmet_rdma] nvmet_rdma_release_queue_work+0x19/0x50 [nvmet_rdma] process_one_work+0x206/0x660 worker_thread+0x184/0x320 kthread+0x10c/0x240 ret_from_fork+0x319/0x390 Move async event work to a dedicated nvmet-aen-wq to avoid reentrant flush on nvmet-wq. Reviewed-by: Christoph Hellwig Signed-off-by: Chaitanya Kulkarni Signed-off-by: Keith Busch Signed-off-by: Sasha Levin --- drivers/nvme/target/admin-cmd.c | 2 +- drivers/nvme/target/core.c | 14 ++++++++++++-- drivers/nvme/target/nvmet.h | 1 + drivers/nvme/target/rdma.c | 1 + 4 files changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c index 3e378153a7817..950b7f8e8ad56 100644 --- a/drivers/nvme/target/admin-cmd.c +++ b/drivers/nvme/target/admin-cmd.c @@ -1586,7 +1586,7 @@ void nvmet_execute_async_event(struct nvmet_req *req) ctrl->async_event_cmds[ctrl->nr_async_event_cmds++] = req; mutex_unlock(&ctrl->lock); - queue_work(nvmet_wq, &ctrl->async_event_work); + queue_work(nvmet_aen_wq, &ctrl->async_event_work); } void nvmet_execute_keep_alive(struct nvmet_req *req) diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c index 5d7d483bfbe37..1c5b6bab47791 100644 --- a/drivers/nvme/target/core.c +++ b/drivers/nvme/target/core.c @@ -26,6 +26,8 @@ static DEFINE_IDA(cntlid_ida); struct workqueue_struct *nvmet_wq; EXPORT_SYMBOL_GPL(nvmet_wq); +struct workqueue_struct *nvmet_aen_wq; +EXPORT_SYMBOL_GPL(nvmet_aen_wq); /* * This read/write semaphore is used to synchronize access to configuration @@ -205,7 +207,7 @@ void nvmet_add_async_event(struct nvmet_ctrl *ctrl, u8 event_type, list_add_tail(&aen->entry, &ctrl->async_events); mutex_unlock(&ctrl->lock); - queue_work(nvmet_wq, &ctrl->async_event_work); + queue_work(nvmet_aen_wq, &ctrl->async_event_work); } static void nvmet_add_to_changed_ns_log(struct nvmet_ctrl *ctrl, __le32 nsid) @@ -1957,9 +1959,14 @@ static int __init nvmet_init(void) if (!nvmet_wq) goto out_free_buffered_work_queue; + nvmet_aen_wq = alloc_workqueue("nvmet-aen-wq", + WQ_MEM_RECLAIM | WQ_UNBOUND, 0); + if (!nvmet_aen_wq) + goto out_free_nvmet_work_queue; + error = nvmet_init_debugfs(); if (error) - goto out_free_nvmet_work_queue; + goto out_free_nvmet_aen_work_queue; error = nvmet_init_discovery(); if (error) @@ -1975,6 +1982,8 @@ static int __init nvmet_init(void) nvmet_exit_discovery(); out_exit_debugfs: nvmet_exit_debugfs(); +out_free_nvmet_aen_work_queue: + destroy_workqueue(nvmet_aen_wq); out_free_nvmet_work_queue: destroy_workqueue(nvmet_wq); out_free_buffered_work_queue: @@ -1992,6 +2001,7 @@ static void __exit nvmet_exit(void) nvmet_exit_discovery(); nvmet_exit_debugfs(); ida_destroy(&cntlid_ida); + destroy_workqueue(nvmet_aen_wq); destroy_workqueue(nvmet_wq); destroy_workqueue(buffered_io_wq); destroy_workqueue(zbd_wq); diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h index f3b09f4099f08..059fd9f356c45 100644 --- a/drivers/nvme/target/nvmet.h +++ b/drivers/nvme/target/nvmet.h @@ -502,6 +502,7 @@ extern struct kmem_cache *nvmet_bvec_cache; extern struct workqueue_struct *buffered_io_wq; extern struct workqueue_struct *zbd_wq; extern struct workqueue_struct *nvmet_wq; +extern struct workqueue_struct *nvmet_aen_wq; static inline void nvmet_set_result(struct nvmet_req *req, u32 result) { diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c index 0485e25ab797c..284ab759bbce3 100644 --- a/drivers/nvme/target/rdma.c +++ b/drivers/nvme/target/rdma.c @@ -2088,6 +2088,7 @@ static void nvmet_rdma_remove_one(struct ib_device *ib_device, void *client_data mutex_unlock(&nvmet_rdma_queue_mutex); flush_workqueue(nvmet_wq); + flush_workqueue(nvmet_aen_wq); } static struct ib_client nvmet_rdma_ib_client = { -- 2.51.0