PCI: take the rescan lock when adding devices during host probe
PATCH v2 1/1 PCI: take the rescan lock when adding devices during host probe
From: Bartosz Golaszewski <[email protected]>
Since adding the PCI power control code, we may end up with a race between the pwrctl platform device rescanning the bus and the host controller probe function. The latter needs 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
---
v1 -> v2:
- improve the commit message, add example stack trace
drivers/pci/probe.c | 2 ++ 1 file changed, 2 insertions(+)
drivers/pci/probe.c +2 -0
@@ -3105,7 +3105,9 @@ 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);
Signature · 1 line
2.30.2
Quoted 19 lines · Bartosz Golaszewski
From: Bartosz Golaszewski <[email protected]>
Since adding the PCI power control code, we may end up with a race between the pwrctl platform device rescanning the bus and the host controller probe function. The latter needs 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
Quoted 9 lines
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
Thanks for adding the crash log. It always helps to have the log in patch description to find *this* patch.
Quoted 4 lines
Reported-by Konrad Dybcio <[email protected]>Tested-by Konrad Dybcio <[email protected]>Fixes 4565d2652a37 ("PCI/pwrctl: Add PCI power control core code")Signed-off-by Bartosz Golaszewski <[email protected]>
- Mani
Quoted 25 lines
---
v1 -> v2:
- improve the commit message, add example stack tracedrivers/pci/probe.c | 2 ++ 1 file changed, 2 insertions(+)drivers/pci/probe.c +2
-0@@ -3105,7 +3105,9 @@ 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);Signature · 1 line
2.30.2
Signature · 1 line
மணிவண்ணன் சதாசிவம்
Quoted 29 lines · Bartosz Golaszewski
From: Bartosz Golaszewski <[email protected]>
Since adding the PCI power control code, we may end up with a race between the pwrctl platform device rescanning the bus and the host controller probe function. The latter needs 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
Quoted 5 lines
Reported-by Konrad Dybcio <[email protected]>Tested-by Konrad Dybcio <[email protected]>Fixes 4565d2652a37 ("PCI/pwrctl: Add PCI power control core code")Signed-off-by Bartosz Golaszewski <[email protected]>---
It's been a week, so gentle ping - can this be picked up into v6.12?
Thanks,
Bartosz
Quoted 30 lines · Bartosz Golaszewski
Quoted 29 lines · Bartosz Golaszewski
From: Bartosz Golaszewski <[email protected]>
Since adding the PCI power control code, we may end up with a race between the pwrctl platform device rescanning the bus and the host controller probe function. The latter needs 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
Quoted 7 lines
Quoted 5 lines
Reported-by Konrad Dybcio <[email protected]>Tested-by Konrad Dybcio <[email protected]>Fixes 4565d2652a37 ("PCI/pwrctl: Add PCI power control core code")Signed-off-by Bartosz Golaszewski <[email protected]>---
It's been a week, so gentle ping - can this be picked up into v6.12?
I hoped we could fix the similar latent issues in other drivers, but yes, we can get this in v6.12. Thanks for the hint that it should go there. I'll pick it up when I return from vacation on Wednesday.
Bjorn
Quoted 38 lines · Bjorn Helgaas
Quoted 36 lines · Bartosz Golaszewski
Quoted 34 lines · Bartosz Golaszewski
From: Bartosz Golaszewski <[email protected]>
Since adding the PCI power control code, we may end up with a race between the pwrctl platform device rescanning the bus and the host controller probe function. The latter needs 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/0xecReported-by Konrad Dybcio <[email protected]>Tested-by Konrad Dybcio <[email protected]>Fixes 4565d2652a37 ("PCI/pwrctl: Add PCI power control core code")Signed-off-by Bartosz Golaszewski <[email protected]>---
Quoted 6 lines
Quoted 1 line
It's been a week, so gentle ping - can this be picked up into v6.12?
I hoped we could fix the similar latent issues in other drivers, but yes, we can get this in v6.12. Thanks for the hint that it should go there. I'll pick it up when I return from vacation on Wednesday.
Sure this can still be done but this patch fixes an urgent issue and I think it warrants fast tracking it to mainline.
Bart