• Grygorii Strashko's avatar
    PCI: host: Mark PCIe/PCI (MSI) IRQ cascade handlers as IRQF_NO_THREAD · 8ff0ef99
    Grygorii Strashko authored
    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: default avatarGrygorii Strashko <grygorii.strashko@ti.com>
    Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
    Acked-by: Lucas Stach <l.stach@pengutronix.de> (for imx6)
    CC: stable@vger.kernel.org
    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>
    8ff0ef99
pci-imx6.c 17.3 KB