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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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Dexuan Cui
5661d43b03
commit021ad274d7upstream. When we hot-remove the device, we first receive a PCI_EJECT message and then receive a PCI_BUS_RELATIONS message with bus_rel->device_count == 0. The first message is offloaded to hv_eject_device_work(), and the second is offloaded to pci_devices_present_work(). Both the paths can be running list_del(&hpdev->list_entry), causing general protection fault, because system_wq can run them concurrently. The patch eliminates the race condition. Since access to present/eject work items is serialized, we do not need the hbus->enum_sem anymore, so remove it. Fixes:4daace0d8c("PCI: hv: Add paravirtual PCI front-end for Microsoft Hyper-V VMs") Link: https://lkml.kernel.org/r/KL1P15301MB00064DA6B4D221123B5241CFBFD70@KL1P15301MB0006.APCP153.PROD.OUTLOOK.COM Tested-by: Adrian Suhov <v-adsuho@microsoft.com> Tested-by: Chris Valean <v-chvale@microsoft.com> Signed-off-by: Dexuan Cui <decui@microsoft.com> [lorenzo.pieralisi@arm.com: squashed semaphore removal patch] Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Acked-by: Haiyang Zhang <haiyangz@microsoft.com> Cc: <stable@vger.kernel.org> # v4.6+ Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Jack Morgenstein <jackm@mellanox.com> Cc: Stephen Hemminger <sthemmin@microsoft.com> Cc: K. Y. Srinivasan <kys@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.