Messages in this thread | | | Date | Wed, 13 Nov 2019 07:35:19 +0100 | From | Lukas Wunner <> | Subject | Re: [PATCH v3 2/2] PCI: pciehp: Prevent deadlock on disconnect |
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On Tue, Nov 12, 2019 at 09:17:52PM -0600, Bjorn Helgaas wrote: > On Tue, Oct 29, 2019 at 08:00:22PM +0300, Mika Westerberg wrote: > > parent PCIe downstream port, who got the hot-remove event, starts > > removing devices below it taking pci_lock_rescan_remove() lock. When the > > child PCIe port is runtime resumed it calls pciehp_check_presence() > > which ends up calling pciehp_card_present() and pciehp_check_link_active(). > > Oh, I see, pciehp_resume() calls pciehp_check_presence(), which > schedules the IRQ thread via pciehp_request(). So does this deadlock > only happen if the port(s) have been runtime suspended?
No, there is a multitude of situations when the deadlock may occur and this is just one of them. See my comment on v1 of this patch:
https://patchwork.ozlabs.org/patch/1117870/#2230798
Thanks,
Lukas
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