From: Long Li longli@microsoft.com
[ Upstream commit 41608b64b10b80fe00dd253cd8326ec8ad85930f ]
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" kys@microsoft.com Cc: Haiyang Zhang haiyangz@microsoft.com Cc: Stephen Hemminger sthemmin@microsoft.com Cc: Wei Liu wei.liu@kernel.org Cc: Dexuan Cui decui@microsoft.com Cc: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Cc: Rob Herring robh@kernel.org Cc: "Krzysztof Wilczyński" kw@linux.com Cc: Bjorn Helgaas bhelgaas@google.com Cc: Michael Kelley mikelley@microsoft.com Reported-by: Dan Carpenter dan.carpenter@oracle.com Link: https://lore.kernel.org/linux-hyperv/20210823152130.GA21501@kili/ Signed-off-by: Long Li longli@microsoft.com Reviewed-by: Wei Liu wei.liu@kernel.org Link: https://lore.kernel.org/r/1630365207-20616-1-git-send-email-longli@linuxonhy... Signed-off-by: Wei Liu wei.liu@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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);