@@ -535,7 +535,8 @@ static int __init add_pcie_port(struct pcie_port *pp,
ret = devm_request_irq(&pdev->dev, pp->msi_irq,
exynos_pcie_msi_irq_handler,
- IRQF_SHARED, "exynos-pcie", pp);
+ IRQF_SHARED | IRQF_NO_THREAD,
+ "exynos-pcie", pp);
if (ret) {
dev_err(&pdev->dev, "failed to request msi irq\n");
return ret;
@@ -497,7 +497,8 @@ static int __init imx6_add_pcie_port(struct pcie_port *pp,
ret = devm_request_irq(&pdev->dev, pp->msi_irq,
imx6_pcie_msi_handler,
- IRQF_SHARED, "mx6-pcie-msi", pp);
+ IRQF_SHARED | IRQF_NO_THREAD,
+ "mx6-pcie-msi", pp);
if (ret) {
dev_err(&pdev->dev, "failed to request MSI irq\n");
return -ENODEV;
@@ -1280,7 +1280,7 @@ static int tegra_pcie_enable_msi(struct tegra_pcie *pcie)
msi->irq = err;
- err = request_irq(msi->irq, tegra_pcie_msi_irq, 0,
+ err = request_irq(msi->irq, tegra_pcie_msi_irq, IRQF_NO_THREAD,
tegra_msi_irq_chip.name, pcie);
if (err < 0) {
dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
@@ -712,14 +712,16 @@ static int rcar_pcie_enable_msi(struct rcar_pcie *pcie)
/* Two irqs are for MSI, but they are also used for non-MSI irqs */
err = devm_request_irq(&pdev->dev, msi->irq1, rcar_pcie_msi_irq,
- IRQF_SHARED, rcar_msi_irq_chip.name, pcie);
+ IRQF_SHARED | IRQF_NO_THREAD,
+ rcar_msi_irq_chip.name, pcie);
if (err < 0) {
dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
goto err;
}
err = devm_request_irq(&pdev->dev, msi->irq2, rcar_pcie_msi_irq,
- IRQF_SHARED, rcar_msi_irq_chip.name, pcie);
+ IRQF_SHARED | IRQF_NO_THREAD,
+ rcar_msi_irq_chip.name, pcie);
if (err < 0) {
dev_err(&pdev->dev, "failed to request IRQ: %d\n", err);
goto err;
This is a note to let you know that I have just added a patch titled PCI: host: Mark PCIe/PCI (MSI) IRQ cascade handlers as IRQF_NO_THREAD to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue This patch is scheduled to be released in version 3.16.7-ckt24. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.16.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Luis ---8<------------------------------------------------------------ From 3d238df7b81dbd0d558e0badb0869f623e3095fb Mon Sep 17 00:00:00 2001 From: Grygorii Strashko <grygorii.strashko@ti.com> Date: Thu, 10 Dec 2015 21:18:20 +0200 Subject: PCI: host: Mark PCIe/PCI (MSI) IRQ cascade handlers as IRQF_NO_THREAD MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit 8ff0ef996ca00028519c70e8d51d32bd37eb51dc upstream. On -RT and if kernel is booting with "threadirqs" cmd line parameter, PCIe/PCI (MSI) IRQ cascade handlers (like dra7xx_pcie_msi_irq_handler()) will be forced threaded and, as result, will generate warnings like this: WARNING: CPU: 1 PID: 82 at kernel/irq/handle.c:150 handle_irq_event_percpu+0x14c/0x174() irq 460 handler irq_default_primary_handler+0x0/0x14 enabled interrupts Backtrace: (warn_slowpath_common) from (warn_slowpath_fmt+0x38/0x40) (warn_slowpath_fmt) from (handle_irq_event_percpu+0x14c/0x174) (handle_irq_event_percpu) from (handle_irq_event+0x84/0xb8) (handle_irq_event) from (handle_simple_irq+0x90/0x118) (handle_simple_irq) from (generic_handle_irq+0x30/0x44) (generic_handle_irq) from (dra7xx_pcie_msi_irq_handler+0x7c/0x8c) (dra7xx_pcie_msi_irq_handler) from (irq_forced_thread_fn+0x28/0x5c) (irq_forced_thread_fn) from (irq_thread+0x128/0x204) This happens because all of them invoke generic_handle_irq() from the requested handler. generic_handle_irq() grabs raw_locks and thus needs to run in raw-IRQ context. This issue was originally reproduced on TI dra7-evem, but, as was identified during discussion [1], other hosts can also suffer from this issue. Fix all them at once by marking PCIe/PCI (MSI) IRQ cascade handlers IRQF_NO_THREAD explicitly. [1] http://lkml.kernel.org/r/1448027966-21610-1-git-send-email-grygorii.strashko@ti.com [bhelgaas: add stable tag, fix typos] Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Lucas Stach <l.stach@pengutronix.de> (for imx6) CC: Kishon Vijay Abraham I <kishon@ti.com> CC: Jingoo Han <jingoohan1@gmail.com> CC: Kukjin Kim <kgene@kernel.org> CC: Krzysztof Kozlowski <k.kozlowski@samsung.com> CC: Richard Zhu <Richard.Zhu@freescale.com> CC: Thierry Reding <thierry.reding@gmail.com> CC: Stephen Warren <swarren@wwwdotorg.org> CC: Alexandre Courbot <gnurou@gmail.com> CC: Simon Horman <horms@verge.net.au> CC: Pratyush Anand <pratyush.anand@gmail.com> CC: Michal Simek <michal.simek@xilinx.com> CC: "Sören Brinkmann" <soren.brinkmann@xilinx.com> CC: Sebastian Andrzej Siewior <bigeasy@linutronix.de> [ luis: backported to 3.16: - dropped changes to pci-dra7xx.c, pcie-spear13xx.c, pcie-xilinx.c - adjusted context ] Signed-off-by: Luis Henriques <luis.henriques@canonical.com> --- drivers/pci/host/pci-exynos.c | 3 ++- drivers/pci/host/pci-imx6.c | 3 ++- drivers/pci/host/pci-tegra.c | 2 +- drivers/pci/host/pcie-rcar.c | 6 ++++-- 4 files changed, 9 insertions(+), 5 deletions(-)