Before the guest finishes probing a device, the host may be already starting to remove the device. Currently there are multiple race condition bugs in the pci-hyperv driver, which can cause the guest to panic. The patchset fixes the crashes. The patchset also does some cleanup work: patch 3 removes the useless hv_pcichild_state, and patch 4 reverts an old patch which is not really useful (without patch 4, it would be hard to make patch 5 clean). Patch 6 removes the use of a global mutex lock, and enables async-probing to allow concurrent device probing for faster boot. In v2, I dropped the "debug code" before the real patch body to avoid confusion; I fixed some minor issues pointed out by Michael Kelely: fixed "goto release_state_lock" in patch 5, and improved the commit log of patch 6; I added Wei Hu's Acked-by to patch 4. I added the cc:stable tag to all the 6 patches. v2 is based on v6.3-rc5. I have been testing the patchset with https://lwn.net/ml/linux-kernel/20230316091540.494366-1-alexander.stein%40ew.tq-group.com/ for several days, and no panic/hang is observed (earlier the kernel would panic/hang within 1 day in my long haul testing). The patchset is also availsble in my github branch: https://github.com/dcui/tdx/commits/decui/vpci/v6.3-rc5-v2 v1 can be found here: https://lwn.net/ml/linux-kernel/20230328045122.25850-1-decui%40microsoft.com/ Please review. Thanks! Dexuan Cui (6): PCI: hv: Fix a race condition bug in hv_pci_query_relations() PCI: hv: Fix a race condition in hv_irq_unmask() that can cause panic PCI: hv: Remove the useless hv_pcichild_state from struct hv_pci_dev Revert "PCI: hv: Fix a timing issue which causes kdump to fail occasionally" PCI: hv: Add a per-bus mutex state_lock PCI: hv: Use async probing to reduce boot time drivers/pci/controller/pci-hyperv.c | 145 +++++++++++++++++----------- 1 file changed, 86 insertions(+), 59 deletions(-) -- 2.25.1
