6.11-stable review patch. If anyone has any objections, please let me know.
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From: Bartosz Golaszewski bartosz.golaszewski@linaro.org
[ Upstream commit 1d59d474e1cb7d4fdf87dfaf96f44647f13ea590 ]
Since adding the PCI power control code, we may end up with a race between the pwrctl platform device rescanning the bus and host controller probe functions. The latter need to take the rescan lock when adding devices or we may end up in an undefined state having two incompletely added devices and hit the following crash when trying to remove the device over sysfs:
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000 Internal error: Oops: 0000000096000004 [#1] SMP Call trace: __pi_strlen+0x14/0x150 kernfs_find_ns+0x80/0x13c kernfs_remove_by_name_ns+0x54/0xf0 sysfs_remove_bin_file+0x24/0x34 pci_remove_resource_files+0x3c/0x84 pci_remove_sysfs_dev_files+0x28/0x38 pci_stop_bus_device+0x8c/0xd8 pci_stop_bus_device+0x40/0xd8 pci_stop_and_remove_bus_device_locked+0x28/0x48 remove_store+0x70/0xb0 dev_attr_store+0x20/0x38 sysfs_kf_write+0x58/0x78 kernfs_fop_write_iter+0xe8/0x184 vfs_write+0x2dc/0x308 ksys_write+0x7c/0xec
Fixes: 4565d2652a37 ("PCI/pwrctl: Add PCI power control core code") Link: https://lore.kernel.org/r/20241003084342.27501-1-brgl@bgdev.pl Reported-by: Konrad Dybcio konradybcio@kernel.org Tested-by: Konrad Dybcio konradybcio@kernel.org Signed-off-by: Bartosz Golaszewski bartosz.golaszewski@linaro.org Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Manivannan Sadhasivam manivannan.sadhasivam@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/probe.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index e9e56bbb3b59d..d203e23b75620 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -3106,7 +3106,9 @@ int pci_host_probe(struct pci_host_bridge *bridge) list_for_each_entry(child, &bus->children, node) pcie_bus_configure_settings(child);
+ pci_lock_rescan_remove(); pci_bus_add_devices(bus); + pci_unlock_rescan_remove(); return 0; } EXPORT_SYMBOL_GPL(pci_host_probe);