From 41608b64b10b80fe00dd253cd8326ec8ad85930f Mon Sep 17 00:00:00 2001 From: Long Li Date: Mon, 30 Aug 2021 16:13:27 -0700 Subject: [PATCH 1/3] PCI: hv: Fix sleep while in non-sleep context when removing child devices from the bus MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In hv_pci_bus_exit, the code is holding a spinlock while calling pci_destroy_slot(), which takes a mutex. This is not safe for spinlock. Fix this by moving the children to be deleted to a list on the stack, and removing them after spinlock is released. Fixes: 94d22763207a ("PCI: hv: Fix a race condition when removing the device") Cc: "K. Y. Srinivasan" Cc: Haiyang Zhang Cc: Stephen Hemminger Cc: Wei Liu Cc: Dexuan Cui Cc: Lorenzo Pieralisi Cc: Rob Herring Cc: "Krzysztof Wilczyński" Cc: Bjorn Helgaas Cc: Michael Kelley Reported-by: Dan Carpenter Link: https://lore.kernel.org/linux-hyperv/20210823152130.GA21501@kili/ Signed-off-by: Long Li Reviewed-by: Wei Liu Link: https://lore.kernel.org/r/1630365207-20616-1-git-send-email-longli@linuxonhyperv.com Signed-off-by: Wei Liu --- drivers/pci/controller/pci-hyperv.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c index a53bd8728d0d..fc1a29acadbb 100644 --- a/drivers/pci/controller/pci-hyperv.c +++ b/drivers/pci/controller/pci-hyperv.c @@ -3229,9 +3229,17 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs) return 0; if (!keep_devs) { - /* Delete any children which might still exist. */ + struct list_head removed; + + /* Move all present children to the list on stack */ + INIT_LIST_HEAD(&removed); spin_lock_irqsave(&hbus->device_list_lock, flags); - list_for_each_entry_safe(hpdev, tmp, &hbus->children, list_entry) { + list_for_each_entry_safe(hpdev, tmp, &hbus->children, list_entry) + list_move_tail(&hpdev->list_entry, &removed); + spin_unlock_irqrestore(&hbus->device_list_lock, flags); + + /* Remove all children in the list */ + list_for_each_entry_safe(hpdev, tmp, &removed, list_entry) { list_del(&hpdev->list_entry); if (hpdev->pci_slot) pci_destroy_slot(hpdev->pci_slot); @@ -3239,7 +3247,6 @@ static int hv_pci_bus_exit(struct hv_device *hdev, bool keep_devs) put_pcichild(hpdev); put_pcichild(hpdev); } - spin_unlock_irqrestore(&hbus->device_list_lock, flags); } ret = hv_send_resources_released(hdev); From 95a13ee858c9e426e63c97063677736f74af7163 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Fri, 1 Oct 2021 16:55:44 +0300 Subject: [PATCH 2/3] hyper-v: Replace uuid.h with types.h There is no user of anything in uuid.h in the hyperv.h. Replace it with more appropriate types.h. Fixes: f081bbb3fd03 ("hyper-v: Remove internal types from UAPI header") Reported-by: Greg Kroah-Hartman Signed-off-by: Andy Shevchenko Reviewed-by: Haiyang Zhang Link: https://lore.kernel.org/r/20211001135544.1823-1-andriy.shevchenko@linux.intel.com Signed-off-by: Wei Liu --- include/uapi/linux/hyperv.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/uapi/linux/hyperv.h b/include/uapi/linux/hyperv.h index 6135d92e0d47..daf82a230c0e 100644 --- a/include/uapi/linux/hyperv.h +++ b/include/uapi/linux/hyperv.h @@ -26,7 +26,7 @@ #ifndef _UAPI_HYPERV_H #define _UAPI_HYPERV_H -#include +#include /* * Framework version for util services. From f5c20e4a5f18677e22d8dd2846066251b006a62d Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Wed, 6 Oct 2021 14:50:16 +0200 Subject: [PATCH 3/3] x86/hyperv: Avoid erroneously sending IPI to 'self' __send_ipi_mask_ex() uses an optimization: when the target CPU mask is equal to 'cpu_present_mask' it uses 'HV_GENERIC_SET_ALL' format to avoid converting the specified cpumask to VP_SET. This case was overlooked when 'exclude_self' parameter was added. As the result, a spurious IPI to 'self' can be send. Reported-by: Thomas Gleixner Fixes: dfb5c1e12c28 ("x86/hyperv: remove on-stack cpumask from hv_send_ipi_mask_allbutself") Signed-off-by: Vitaly Kuznetsov Reviewed-by: Michael Kelley Link: https://lore.kernel.org/r/20211006125016.941616-1-vkuznets@redhat.com Signed-off-by: Wei Liu --- arch/x86/hyperv/hv_apic.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/arch/x86/hyperv/hv_apic.c b/arch/x86/hyperv/hv_apic.c index 32a1ad356c18..db2d92fb44da 100644 --- a/arch/x86/hyperv/hv_apic.c +++ b/arch/x86/hyperv/hv_apic.c @@ -122,17 +122,27 @@ static bool __send_ipi_mask_ex(const struct cpumask *mask, int vector, ipi_arg->reserved = 0; ipi_arg->vp_set.valid_bank_mask = 0; - if (!cpumask_equal(mask, cpu_present_mask)) { + /* + * Use HV_GENERIC_SET_ALL and avoid converting cpumask to VP_SET + * when the IPI is sent to all currently present CPUs. + */ + if (!cpumask_equal(mask, cpu_present_mask) || exclude_self) { ipi_arg->vp_set.format = HV_GENERIC_SET_SPARSE_4K; if (exclude_self) nr_bank = cpumask_to_vpset_noself(&(ipi_arg->vp_set), mask); else nr_bank = cpumask_to_vpset(&(ipi_arg->vp_set), mask); - } - if (nr_bank < 0) - goto ipi_mask_ex_done; - if (!nr_bank) + + /* + * 'nr_bank <= 0' means some CPUs in cpumask can't be + * represented in VP_SET. Return an error and fall back to + * native (architectural) method of sending IPIs. + */ + if (nr_bank <= 0) + goto ipi_mask_ex_done; + } else { ipi_arg->vp_set.format = HV_GENERIC_SET_ALL; + } status = hv_do_rep_hypercall(HVCALL_SEND_IPI_EX, 0, nr_bank, ipi_arg, NULL);