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[ Upstream commit 82a979265638c505e12fbe7ba40980dc0901436d ] The pci_request_irq() interfaces always adds the IRQF_SHARED bit to all IRQ requests. When the kernel is built with CONFIG_DEBUG_SHIRQ config flag, if the IRQF_SHARED bit is set, a call to the IRQ handler is made from the __free_irq() function. This is testing a race condition between the IRQ cleanup and an IRQ racing the cleanup. The HFI driver should be able to handle this race, but does not. This race can cause traces that start with this footprint: BUG: unable to handle kernel NULL pointer dereference at (null) Call Trace: <hfi1 irq handler> ... __free_irq+0x1b3/0x2d0 free_irq+0x35/0x70 pci_free_irq+0x1c/0x30 clean_up_interrupts+0x53/0xf0 [hfi1] hfi1_start_cleanup+0x122/0x190 [hfi1] postinit_cleanup+0x1d/0x280 [hfi1] remove_one+0x233/0x250 [hfi1] pci_device_remove+0x39/0xc0 Export IRQ cleanup function so it can be called from other modules. Using the exported cleanup function: Re-order the driver cleanup code to clean up IRQ resources before other resources, eliminating the race. Re-order error path for init so that the race does not occur. Reduce severity on spurious error message for SDMA IRQs to info. Reviewed-by: Alex Estrin <alex.estrin@intel.com> Reviewed-by: Patel Jay P <jay.p.patel@intel.com> Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com> Signed-off-by: Jason Gunthorpe <jgg@mellanox.com> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.