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 37A8F2F24 for ; Wed, 12 Apr 2023 08:50:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5C55C4339B; Wed, 12 Apr 2023 08:50:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1681289413; bh=VNoa/RGHMVWGj69YpT8U/IOouX9L85GcZPpF2qzZjS4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0F7KkZYoAk+iR94j9zAXmRSTbR8K3W30ojZAIjGO7iLyjnBPDSTF3WFiOJjeAO1Bn h9N+7j/cLvhHFVwSW+mk+uW/+i3tY+KLZBAgFK6p2ljvGizlN3F2Hoicv5A408wIw/ /evGmHnalPiZTofxjylMy4mDMiNd8lJqUaMa7vgc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Gregory Price , Ira Weiny , Lukas Wunner , Dan Williams , Jonathan Cameron , Bjorn Helgaas Subject: [PATCH 6.2 059/173] PCI/DOE: Silence WARN splat with CONFIG_DEBUG_OBJECTS=y Date: Wed, 12 Apr 2023 10:33:05 +0200 Message-Id: <20230412082840.492937638@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230412082838.125271466@linuxfoundation.org> References: <20230412082838.125271466@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Lukas Wunner commit 92dc899c3b4927f3cfa23f55bf759171234b5802 upstream. Gregory Price reports a WARN splat with CONFIG_DEBUG_OBJECTS=y upon CXL probing because pci_doe_submit_task() invokes INIT_WORK() instead of INIT_WORK_ONSTACK() for a work_struct that was allocated on the stack. All callers of pci_doe_submit_task() allocate the work_struct on the stack, so replace INIT_WORK() with INIT_WORK_ONSTACK() as a backportable short-term fix. The long-term fix implemented by a subsequent commit is to move to a synchronous API which allocates the work_struct internally in the DOE library. Stacktrace for posterity: WARNING: CPU: 0 PID: 23 at lib/debugobjects.c:545 __debug_object_init.cold+0x18/0x183 CPU: 0 PID: 23 Comm: kworker/u2:1 Not tainted 6.1.0-0.rc1.20221019gitaae703b02f92.17.fc38.x86_64 #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 Call Trace: pci_doe_submit_task+0x5d/0xd0 pci_doe_discovery+0xb4/0x100 pcim_doe_create_mb+0x219/0x290 cxl_pci_probe+0x192/0x430 local_pci_probe+0x41/0x80 pci_device_probe+0xb3/0x220 really_probe+0xde/0x380 __driver_probe_device+0x78/0x170 driver_probe_device+0x1f/0x90 __driver_attach_async_helper+0x5c/0xe0 async_run_entry_fn+0x30/0x130 process_one_work+0x294/0x5b0 Fixes: 9d24322e887b ("PCI/DOE: Add DOE mailbox support functions") Link: https://lore.kernel.org/linux-cxl/Y1bOniJliOFszvIK@memverge.com/ Reported-by: Gregory Price Tested-by: Ira Weiny Tested-by: Gregory Price Signed-off-by: Lukas Wunner Reviewed-by: Ira Weiny Reviewed-by: Dan Williams Reviewed-by: Gregory Price Cc: stable@vger.kernel.org # v6.0+ Reviewed-by: Jonathan Cameron Acked-by: Bjorn Helgaas Link: https://lore.kernel.org/r/67a9117f463ecdb38a2dbca6a20391ce2f1e7a06.1678543498.git.lukas@wunner.de Signed-off-by: Dan Williams Signed-off-by: Greg Kroah-Hartman --- drivers/pci/doe.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/pci/doe.c +++ b/drivers/pci/doe.c @@ -523,6 +523,8 @@ EXPORT_SYMBOL_GPL(pci_doe_supports_prot) * task->complete will be called when the state machine is done processing this * task. * + * @task must be allocated on the stack. + * * Excess data will be discarded. * * RETURNS: 0 when task has been successfully queued, -ERRNO on error @@ -544,7 +546,7 @@ int pci_doe_submit_task(struct pci_doe_m return -EIO; task->doe_mb = doe_mb; - INIT_WORK(&task->work, doe_statemachine_work); + INIT_WORK_ONSTACK(&task->work, doe_statemachine_work); queue_work(doe_mb->work_queue, &task->work); return 0; }