[PATCH v6 0/2] platform/x86: p2sb: Fix deadlock at sysfs PCI bus rescan

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



When PCI devices call p2sb_bar() during probe for sysfs PCI bus rescan, deadlock
happens due to double lock of pci_rescan_remove_lock [1]. The first patch in
this series addresses the deadlock. The second patch is a code improvement which
was pointed out during review for the first patch.

[1] https://lore.kernel.org/linux-pci/6xb24fjmptxxn5js2fjrrddjae6twex5bjaftwqsuawuqqqydx@7cl3uik5ef6j/

The first patch of the v5 series was upstreamed to the kernel v6.7-rc8. However,
it caused IDE controller detection failure on an old platform [2] then the patch
was reverted at v6.7. The failure happened because the IDE controller had same
DEVFN as P2SB device. To avoid this failure, I added device class check per
suggestion by Lukas. If the device at P2SB DEVFN does not have the device class
expected for P2SB, avoid touching the device.

[2] https://lore.kernel.org/platform-driver-x86/CABq1_vjfyp_B-f4LAL6pg394bP6nDFyvg110TOLHHb0x4aCPeg@xxxxxxxxxxxxxx/

I confirmed the patches fix the problem [1] on the kernel v6.7, using a system
with i2c_i801 device, building i2c_i801 module as both built-in and loadable.
Reviews and comments will be appreciated.

Klara,

I hesitated to add your Tested-by tag to the v6 patch, since I modified the code
slightly from the code you tested (I used pci_bus_read_config_word() instead of
pci_bus_read_config_dword() to avoid a shift operator). I hope you have time to
afford to test this series again.


Changes from v5:
* Added device class check to avoid old IDE controller detection failure

Changes from v4:
* Separated a hunk for pci_resource_n() as the second patch
* Reflected other review comments by Ilpo

Changes from v3:
* Modified p2sb_valid_resource() to return boolean

Changes from v2:
* Improved p2sb_scan_and_cache() and p2sb_scan_and_cache_devfn()
* Reflected other review comments by Andy

Changes from v1:
* Reflected review comments by Andy
* Removed RFC prefix

Changes from RFC v2:
* Reflected review comments on the list

Changes from RFC v1:
* Fixed a build warning poitned out in llvm list by kernel test robot

Shin'ichiro Kawasaki (2):
  platform/x86: p2sb: Allow p2sb_bar() calls during PCI device probe
  platform/x86: p2sb: Use pci_resource_n() in p2sb_read_bar0()

 drivers/platform/x86/p2sb.c | 183 +++++++++++++++++++++++++++---------
 1 file changed, 141 insertions(+), 42 deletions(-)

-- 
2.43.0





[Index of Archives]     [Linux Kernel Development]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux