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
