B1;2802;0cOn Tue, 7 Jun 2016, Rui Wang wrote: > On a 4-socket brickland, hot-removing one ioapic is fine. Hot-removing > the 2nd one causes panic: > > [ 453.422259] BUG: unable to handle kernel NULL pointer dereference at > 0000000000000030 > [ 453.431059] IP: [<ffffffff8109a8c2>] release_resource+0x22/0x80 <Useless information> > [ 453.437713] PGD 0 > [ 453.439976] Oops: 0000 [#1] SMP > [ 453.698876] ffff88046267fd20 ffffffff8104e3ff 0000000000000000 > ffff88046267fd58 </Useless information> > [ 453.707195] Call Trace: > [ 453.709935] [<ffffffff81057965>] mp_unregister_ioapic+0x125/0x180 > [ 453.716846] [<ffffffff8104e3ff>] acpi_unregister_ioapic+0x1f/0x40 > [ 453.723759] [<ffffffff8140cfe3>] acpi_ioapic_remove+0x5f/0xf0 > [ 453.730283] [<ffffffff813e0645>] acpi_pci_root_remove+0x2c/0x80 > [ 453.737002] [<ffffffff813da86b>] acpi_bus_trim+0x5a/0x8d > [ 453.743039] [<ffffffff813dc31d>] acpi_device_hotplug+0x1b7/0x418 > [ 453.749851] [<ffffffff813d4f8a>] acpi_hotplug_work_fn+0x1e/0x29 <Useless information> > [ 453.756570] [<ffffffff810ad67f>] process_one_work+0x14f/0x3d0 > [ 453.763092] [<ffffffff810adf35>] worker_thread+0x125/0x4b0 > [ 453.769325] [<ffffffff816fd5c1>] ? __schedule+0x2b1/0x700 > [ 453.775459] [<ffffffff810ade10>] ? rescuer_thread+0x370/0x370 > [ 453.781981] [<ffffffff810b3a58>] kthread+0xd8/0xf0 > [ 453.787435] [<ffffffff810b3980>] ? kthread_park+0x60/0x60 > [ 453.793570] [<ffffffff8170190f>] ret_from_fork+0x3f/0x70 > [ 453.800203] [<ffffffff810b3980>] ? kthread_park+0x60/0x60 > [ 453.806914] Code: 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89 > e5 53 48 89 fb 48 c7 c7 f8 c0 e3 81 e8 87 69 66 00 48 8b 4b 20 b8 ea ff > ff ff <48> 8b 51 30 48 85 d2 74 1d 48 39 d3 75 0a eb 3f 48 39 c3 74 1b > [ 453.829861] RIP [<ffffffff8109a8c2>] release_resource+0x22/0x80 > [ 453.837188] RSP <ffff88046267fcc8> > [ 453.841673] CR2: 0000000000000030 </Useless information> Please trim the dumps to the relevant information > Fix it by assigning the correct pointers to ioapics[i].iomem_res in > ioapic_setup_resources(). This does not explain the splat above. Please explain which pointer is wrong and what effects that has. > Also simplify the function by removing the redundant 'num' variable. Please don't do that. This makes the patch hard to read. Split this into a minimal bugfix, which can be backported and a cleanup patch which gets rid of the extra variable. > - ioapics[i].iomem_res = res; > + ioapics[i].iomem_res = &res[i]; If I read the patch correctly, then this is the fix. Right? So please make it a one liner and send a cleanup patch seperately. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
