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 D52AD246778; Mon, 13 Oct 2025 21:40:34 +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=1760391634; cv=none; b=dcsQ5iXL+g9xaZDRGrM/j08h/XMXZYpilOt7plz4OZ/bX8S8gCJAH4abXFP5XFr1LaphcKbCuv/c1Qz5nZF2ALBY0ker2oUZaz2pDD34U9zZe/9PgqKFKQ6olop2WkOVnGSUybcSbXAVqKQI1DyPEJoVgVdyCHTShvuKKSGuYDQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760391634; c=relaxed/simple; bh=lSBBgblcFkXBDIkspp2NfyRR5bmbe73dKuE4WTS8jDQ=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; b=d5dNi61uV6IerjR9QsknmRjkKBjZAfFXqia+80UQct8lWuujHcpJElVxr2IUYnixmNEMXNWOEv8HHPXEtgty5Z2usF/0nFyRfyxNVe2Wpfp4kEgqvOEla44BwubkVFK0fVS1OE+XYmCKD55q8vf43p/DzjN1MbeJ2BMG+AO70Jc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bHFFebKj; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bHFFebKj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36141C4CEE7; Mon, 13 Oct 2025 21:40:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1760391634; bh=lSBBgblcFkXBDIkspp2NfyRR5bmbe73dKuE4WTS8jDQ=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=bHFFebKjDxDGEhGMg8dyCjd/ziBHfpvK4q3BORNkHxy6RFK/HkSlHnxHNZaJcU+fv zgYNkeG2NOCR2WMjzuK10Vf/JLGyt3NSAxSKOUzzT0w5JTXWhTMH32B9e0gORUeeLa 1B12+EA2ExEmvA5CComPNc2hUZJEl5zFi6c8BmDYcKkO8PvsZJvnDB/9hor3cQUOGU /QUyqn6Dvok+J5IxdL81O7iIDzDNtYNb4ulIBvHSzB54DBrMiFmeTWmaggQA1X05Jp C15zzfjFk3IQ5Xx8Mer/RaiJfA7uvnXQ2Osayog3FfNYUjEDiteOy940e15RnpuBah 9q8TNLDolTX2g== Date: Mon, 13 Oct 2025 16:40:33 -0500 From: Bjorn Helgaas To: Bhanu Seshu Kumar Valluri Cc: mani@kernel.org, kwilczynski@kernel.org, kishon@kernel.org, bhelgaas@google.com, cassel@kernel.org, Frank.Li@nxp.com, dlemoal@kernel.org, christian.bruel@foss.st.com, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] PCI: endpoint: pci-epf-test: Fix sleeping function being called from atomic context Message-ID: <20251013214033.GA865945@bhelgaas> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250930023809.7931-1-bhanuseshukumar@gmail.com> On Tue, Sep 30, 2025 at 08:08:09AM +0530, Bhanu Seshu Kumar Valluri wrote: > When Root Complex(RC) triggers a Doorbell MSI interrupt to Endpoint(EP) it triggers a warning > in the EP. pci_endpoint kselftest target is compiled and used to run the Doorbell test in RC. > > [ 474.686193] BUG: sleeping function called from invalid context at kernel/locking/mutex.c:271 > [ 474.710934] Call trace: > [ 474.710995] __might_resched+0x130/0x158 > [ 474.711011] __might_sleep+0x70/0x88 > [ 474.711023] mutex_lock+0x2c/0x80 > [ 474.711036] pci_epc_get_msi+0x78/0xd8 > [ 474.711052] pci_epf_test_raise_irq.isra.0+0x74/0x138 > [ 474.711063] pci_epf_test_doorbell_handler+0x34/0x50 > > The BUG arises because the EP's pci_epf_test_doorbell_handler is making an > indirect call to pci_epc_get_msi, which uses mutex inside, from interrupt context. > > To fix the issue convert hard irq handler to a threaded irq handler to allow it > to call functions that can sleep during bottom half execution. Register threaded > irq handler with IRQF_ONESHOT to keep interrupt line disabled until the threaded > irq handler completes execution. > > Fixes: eff0c286aa91 ("PCI: endpoint: pci-epf-test: Add doorbell test support") > Signed-off-by: Bhanu Seshu Kumar Valluri Thanks for the fix! It looks like you posted it during the v6.18 merge window, so it was a little bit too late to be included in the v6.18 changes, but it looks like good v6.19 material. Can you please: - Rebase to pci/main (v6.18-rc1) - Add a space before each "(" - Remove the timestamps because they're unnecessary distraction - Add "()" after function names in commit log - s/irq/IRQ/ - Rewrap the commit log to fit in 75 columns - Rewrap the code below to fit in 78 columns because most of the rest of the file does - Carry Niklas' Reviewed-by when you post the v3 > --- > Note : It is compiled and tested on TI am642 board. > > Change log. V1->V2: > Trimmed Call trace to include only essential calls. > Used 12 digit commit ID in fixes tag. > Steps to reproduce the bug are removed from commit log. > Link to V1: https://lore.kernel.org/all/20250917161817.15776-1-bhanuseshukumar@gmail.com/ > > Warnings can be reproduced by following steps below. > *On EP side: > 1. Configure the pci-epf-test function using steps given below > mount -t configfs none /sys/kernel/config > cd /sys/kernel/config/pci_ep/ > mkdir functions/pci_epf_test/func1 > echo 0x104c > functions/pci_epf_test/func1/vendorid > echo 0xb010 > functions/pci_epf_test/func1/deviceid > echo 32 > functions/pci_epf_test/func1/msi_interrupts > echo 2048 > functions/pci_epf_test/func1/msix_interrupts > ln -s functions/pci_epf_test/func1 controllers/f102000.pcie-ep/ > echo 1 > controllers/f102000.pcie-ep/start > > *On RC side: > 1. Once EP side configuration is done do pci rescan. > echo 1 > /sys/bus/pci/rescan > 2. Run Doorbell MSI test using pci_endpoint_test kselftest app. > ./pci_endpoint_test -r pcie_ep_doorbell.DOORBELL_TEST > Note: Kernel is compiled with CONFIG_DEBUG_KERNEL enabled. > > drivers/pci/endpoint/functions/pci-epf-test.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c > index e091193bd8a8..c9e2eb930ad3 100644 > --- a/drivers/pci/endpoint/functions/pci-epf-test.c > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c > @@ -725,8 +725,8 @@ static void pci_epf_test_enable_doorbell(struct pci_epf_test *epf_test, > if (bar < BAR_0) > goto err_doorbell_cleanup; > > - ret = request_irq(epf->db_msg[0].virq, pci_epf_test_doorbell_handler, 0, > - "pci-ep-test-doorbell", epf_test); > + ret = request_threaded_irq(epf->db_msg[0].virq, NULL, pci_epf_test_doorbell_handler, > + IRQF_ONESHOT, "pci-ep-test-doorbell", epf_test); > if (ret) { > dev_err(&epf->dev, > "Failed to request doorbell IRQ: %d\n", > -- > 2.34.1 >