Stefan Richter wrote on 2007-10-13: > bugme-daemon@xxxxxxxxxxxxxxxxxxx wrote: >> http://bugzilla.kernel.org/show_bug.cgi?id=9160 It's a 100% reproducible oops on Sparc (with FireWire controller) for 2.6.23 and 2.6.24 kernels, but not 2.6.22. The reporter confirmed that the bug also happens - with plain 2.6.24-rc5, - with 2.6.23.y and the firewire subsystem fully reverted to that of 2.6.22. This has also been reported independently once before against 2.6.23-rc3, http://marc.info/?l=linux-sparc&m=118751438108687 in August. >> Oct 13 20:26:04 succubus OOPS: Bogus kernel PC [0000000000000000] in fault handler >> Oct 13 20:26:04 succubus OOPS: RPC [0000000010068cd0] >> Oct 13 20:26:04 succubus RPC: <ar_context_add_page+0xd8/0x160 [firewire_ohci]> >> Oct 13 20:26:04 succubus OOPS: Fault was to vaddr[1004e000] >> Oct 13 20:26:04 succubus Call Trace: >> Oct 13 20:26:04 succubus [00000000004076f4] sparc64_realfault_common+0x18/0x20 >> Oct 13 20:26:04 succubus [0000000010068cd0] ar_context_add_page+0xd8/0x160 [firewire_ohci] >> Oct 13 20:26:04 succubus [0000000010068d90] ar_context_init+0x38/0x60 [firewire_ohci] >> Oct 13 20:26:04 succubus [000000001006ac50] pci_probe+0xf8/0x340 [firewire_ohci] >> Oct 13 20:26:04 succubus [00000000005299bc] pci_device_probe+0x64/0xa0 >> Oct 13 20:26:04 succubus [0000000000550a28] driver_probe_device+0x90/0x1c0 >> Oct 13 20:26:04 succubus [0000000000550bc0] __driver_attach+0x68/0x80 >> Oct 13 20:26:04 succubus [000000000054fe5c] bus_for_each_dev+0x44/0x80 >> Oct 13 20:26:04 succubus [0000000000550218] bus_add_driver+0x80/0x1c0 >> Oct 13 20:26:04 succubus [0000000000529b7c] __pci_register_driver+0x44/0xa0 >> Oct 13 20:26:04 succubus [000000000047d5cc] sys_init_module+0x134/0x1400 >> Oct 13 20:26:04 succubus [0000000000406094] linux_sparc_syscall32+0x3c/0x40 >> Oct 13 20:26:04 succubus [00000000000133d8] 0x133e0 >> Oct 13 20:26:04 succubus Unable to handle kernel NULL pointer dereference >> Oct 13 20:26:04 succubus tsk->{mm,active_mm}->context = 00000000000001f9 >> Oct 13 20:26:04 succubus tsk->{mm,active_mm}->pgd = fffff8004f9f8000 [...] The fault happens due to dma_sync_single_for_device() which drivers/firewire/fw-ohci.c calls in ar_context_add_page() when still being in its pci_probe method. I suspect that --- at least on Sparc and after 2.6.22 --- it is not possible anymore to use dma_sync_* before the pci_device's or device's probe was finished. Would that be a bug in the Sparc platform code? Or a bug in driver core code or in PCI code? Or am I expected to refrain from dma_sync_* calls until after the probe returned? (Doing the latter might be tricky, but I suspect that the AR buffers in fw-ohci would generally be better off using coherent allocations. The DMA mapping and syncing in this part of fw-ohci is currently slightly messy.) Thanks for any comments, -- Stefan Richter -=====-=-=== ==-- =--=- http://arcgraph.de/sr/ - To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
