* [bug report] PCI: hv: Fix a race condition when removing the device
@ 2021-08-23 15:21 Dan Carpenter
2021-08-24 7:23 ` Long Li
0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2021-08-23 15:21 UTC (permalink / raw)
To: longli; +Cc: linux-hyperv
Hello Long Li,
The patch 94d22763207a: "PCI: hv: Fix a race condition when removing
the device" from May 12, 2021, leads to the following
Smatch static checker warning:
drivers/pci/controller/pci-hyperv.c:3294 hv_pci_bus_exit()
warn: sleeping in atomic context
drivers/pci/controller/pci-hyperv.c
3287
3288 if (!keep_devs) {
3289 /* Delete any children which might still exist. */
3290 spin_lock_irqsave(&hbus->device_list_lock, flags);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
This takes a spinlock.
3291 list_for_each_entry_safe(hpdev, tmp, &hbus->children, list_entry) {
3292 list_del(&hpdev->list_entry);
3293 if (hpdev->pci_slot)
--> 3294 pci_destroy_slot(hpdev->pci_slot);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
The pci_destroy_slot() function takes a mutex and you can't take a mutex
when you're holding a spinlock because it can sleep.
3295 /* For the two refs got in new_pcichild_device() */
3296 put_pcichild(hpdev);
3297 put_pcichild(hpdev);
3298 }
3299 spin_unlock_irqrestore(&hbus->device_list_lock, flags);
3300 }
3301
3302 ret = hv_send_resources_released(hdev);
3303 if (ret) {
3304 dev_err(&hdev->device,
regards,
dan carpenter
^ permalink raw reply [flat|nested] 2+ messages in thread
* RE: [bug report] PCI: hv: Fix a race condition when removing the device
2021-08-23 15:21 [bug report] PCI: hv: Fix a race condition when removing the device Dan Carpenter
@ 2021-08-24 7:23 ` Long Li
0 siblings, 0 replies; 2+ messages in thread
From: Long Li @ 2021-08-24 7:23 UTC (permalink / raw)
To: Dan Carpenter; +Cc: linux-hyperv
> Subject: [bug report] PCI: hv: Fix a race condition when removing the device
>
> Hello Long Li,
>
> The patch 94d22763207a: "PCI: hv: Fix a race condition when removing the
> device" from May 12, 2021, leads to the following Smatch static checker
> warning:
>
> drivers/pci/controller/pci-hyperv.c:3294 hv_pci_bus_exit()
> warn: sleeping in atomic context
>
> drivers/pci/controller/pci-hyperv.c
> 3287
> 3288 if (!keep_devs) {
> 3289 /* Delete any children which might still exist. */
> 3290 spin_lock_irqsave(&hbus->device_list_lock, flags);
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> This takes a spinlock.
>
> 3291 list_for_each_entry_safe(hpdev, tmp, &hbus->children,
> list_entry) {
> 3292 list_del(&hpdev->list_entry);
> 3293 if (hpdev->pci_slot)
> --> 3294 pci_destroy_slot(hpdev->pci_slot);
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The
> pci_destroy_slot() function takes a mutex and you can't take a mutex when
> you're holding a spinlock because it can sleep.
>
> 3295 /* For the two refs got in new_pcichild_device() */
> 3296 put_pcichild(hpdev);
> 3297 put_pcichild(hpdev);
> 3298 }
> 3299 spin_unlock_irqrestore(&hbus->device_list_lock, flags);
> 3300 }
> 3301
> 3302 ret = hv_send_resources_released(hdev);
> 3303 if (ret) {
> 3304 dev_err(&hdev->device,
>
> regards,
> dan carpenter
Thank you, Dan. I have submitted a patch to fix this.
Long
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-08-23 15:21 [bug report] PCI: hv: Fix a race condition when removing the device Dan Carpenter
2021-08-24 7:23 ` Long Li
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