On Mon, 2013-11-25 at 01:09 +0100, Rafael J. Wysocki wrote: > Hi, > > The following series of four patches (on top of current linux-pm.git/bleeding-edge) > rework child device lookup in drivers/acpi/glue.c and related things: > > [1/4] ACPI / bind: Simplify child device lookup > [2/4] PCI/ ACPI: Use acpi_find_child_device() for child device lookup > [3/4] ACPI / bind: Redefine acpi_get_child() > [4/4] ACPI / bind: Redefine acpi_preset_companion() This patchset caused the attached panic during boot on a system. acpi_pci_find_device() called acpi_find_child_device() with ACPI_COMPANION(dev->parent) being a NULL pointer when scanning bus 0xf. This bus 0xf seems to be a chipset internal bus, which is not intended for the OS to use. Therefore, ACPI does not list its PCI bridge device. # lspci -tv : +-[0000:0f]-+-08.0 Intel Corporation Ivytown QPI Link 0 | +-08.2 Intel Corporation Ivytown QPI Link 0 : However, pcibios_fixup_peer_bridges(), called from pci_subsys_init(), finds this bus as it scans all the buses from 0 to pcibios_last_bus. Hence, this dev->parent does not have an associated ACPI device object. Thanks, -Toshi
: PCI: Discovered peer bus 0f PCI host bridge to bus 0000:0f pci_bus 0000:0f: root bus resource [io 0x0000-0xffff] pci_bus 0000:0f: root bus resource [mem 0x00000000-0x3fffffffffff] pci_bus 0000:0f: No busn resource found for root bus, will use [bus 0f-ff] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 IP: [<ffffffff812da078>] acpi_find_child_device+0x23/0xc3 PGD 0 Oops: 0000 [#1] SMP Modules linked in: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc1+ #504 Hardware name: HP CB920s x1, BIOS Bundle: 005.028.018 SFW: 012.124.000 10/28/2013 task: ffff88085fa5d110 ti: ffff88085fa5e000 task.ti: ffff88085fa5e000 RIP: 0010:[<ffffffff812da078>] [<ffffffff812da078>] acpi_find_child_device+0x23/0xc3 RSP: 0000:ffff88085fa5fbc0 EFLAGS: 00010286 RAX: ffff8a07de1c1800 RBX: ffff88085fa5fc28 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000080000 RDI: 0000000000000000 RBP: ffff88085fa5fbf8 R08: ffff88085ebb2578 R09: 0000000000000000 R10: 0000000000003c0a R11: 0000000000000006 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000080000 FS: 0000000000000000(0000) GS:ffff88087fa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000018 CR3: 0000000001a0b000 CR4: 00000000001407f0 Stack: ffff88085fa5fc10 ffffffff812da3cb ffff88085fa5fc28 ffff88085ebb0098 ffffffff81a7c860 ffff88085ebb0098 00000000ffffffff ffff88085fa5fc10 ffffffff812affde ffff88085ebb00a8 ffff88085fa5fc40 ffffffff812da620 Call Trace: [<ffffffff812da3cb>] ? acpi_bind_one+0x65/0x280 [<ffffffff812affde>] acpi_pci_find_device+0x3e/0x60 [<ffffffff812da620>] acpi_platform_notify+0x3a/0x6c [<ffffffff8135eb4d>] device_add+0x13d/0x640 [<ffffffff81292286>] ? pci_find_capability+0x26/0x50 [<ffffffff8128eea4>] pci_device_add+0x114/0x150 [<ffffffff8153ce41>] pci_scan_single_device+0x91/0xc0 [<ffffffff8128ef2e>] pci_scan_slot+0x4e/0x150 [<ffffffff8128fd7d>] pci_scan_child_bus+0x3d/0x150 [<ffffffff81290090>] pci_scan_root_bus+0xa0/0xb0 [<ffffffff8146551c>] pci_scan_bus_on_node+0x7c/0xd0 [<ffffffff81463ea7>] pcibios_scan_specific_bus+0x97/0xa0 [<ffffffff81b32e62>] ? pci_legacy_init+0x37/0x37 [<ffffffff81b32e98>] pci_subsys_init+0x36/0x48 [<ffffffff81000312>] do_one_initcall+0xf2/0x1a0 [<ffffffff81067fcd>] ? parse_args+0x21d/0x3f0 [<ffffffff81aee047>] kernel_init_freeable+0x18f/0x21a [<ffffffff81aed833>] ? do_early_param+0x88/0x88 [<ffffffff81539fe0>] ? rest_init+0x80/0x80 [<ffffffff81539fee>] kernel_init+0xe/0x130 [<ffffffff815563ec>] ret_from_fork+0x7c/0xb0 [<ffffffff81539fe0>] ? rest_init+0x80/0x80 Code: ff ff 5a 5b 41 5c 5d c3 0f 1f 44 00 00 55 48 89 e5 41 57 49 89 f7 41 56 45 31 f6 41 55 44 0f b6 ea 41 54 45 31 e4 53 48 83 ec 10 <48> 8b 47 18 48 8d 58 d8 48 8d 47 18 48 89 45 c8 48 8d 43 28 48 RIP [<ffffffff812da078>] acpi_find_child_device+0x23/0xc3 RSP <ffff88085fa5fbc0> CR2: 0000000000000018 ---[ end trace 752051e71cfc0265 ]--- Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
