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
[ 453.437713] PGD 0
[ 453.439976] Oops: 0000 [#1] SMP
[ 453.443610] Modules linked in: fuse btrfs xor raid6_pq msdos ext4
mbcache jbd2 binfmt_misc xt_CHECKSUM ipt_MAS
QUERADE nf_nat_masquerade_ipv4 tun ip6t_rpfilter ip6t_REJECT
nf_reject_ipv6 ipt_REJECT nf_reject_ipv4 xt_conntrac
k ebtable_nat ebtable_broute bridge stp llc ebtable_filter ebtables
ip6table_nat nf_conntrack_ipv6 nf_defrag_ipv6
nf_nat_ipv6 ip6table_mangle ip6table_security ip6table_raw
ip6table_filter ip6_tables iptable_nat nf_conntrack_i
pv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack iptable_mangle
iptable_security iptable_raw iptable_filter vfa
t fat x86_pkg_temp_thermal intel_powerclamp coretemp kvm sb_edac
irqbypass edac_core aesni_intel ipmi_ssif iTCO_w
dt iTCO_vendor_support lpc_ich glue_helper ipmi_si ablk_helper sg shpchp
pcspkr mfd_core i2c_i801 ipmi_msghandler
wmi acpi_pad nfsd
[ 453.523040] auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs
libcrc32c sr_mod cdrom sd_mod mgag200 drm_km
s_helper syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm ixgbe igb
ahci libahci libata mdio i2c_algo_bit pt
p i2c_core megaraid_sas pps_core dca dm_mirror dm_region_hash dm_log
dm_mod
[ 453.551438] CPU: 34 PID: 1146 Comm: kworker/u288:1 Not tainted
4.5.0-rc1+ #69
[ 453.559418] Hardware name: Intel Corporation BRICKLAND/BRICKLAND,
BIOS BRHSXSD1.86B.0063.R00.1503261059 03/26/
2015
[ 453.570994] Workqueue: kacpi_hotplug acpi_hotplug_work_fn
[ 453.577041] task: ffff880463325800 ti: ffff88046267c000 task.ti:
ffff88046267c000
[ 453.585415] RIP: 0010:[<ffffffff8109a8c2>] [<ffffffff8109a8c2>]
release_resource+0x22/0x80
[ 453.594768] RSP: 0018:ffff88046267fcc8 EFLAGS: 00010246
[ 453.600706] RAX: 00000000ffffffea RBX: ffff88087fffde00 RCX:
0000000000000000
[ 453.608684] RDX: 00000000000000ff RSI: ffffea0011b72180 RDI:
ffffffff81e3c0f8
[ 453.616663] RBP: ffff88046267fcd0 R08: ffff88046dc86fc0 R09:
00000001802a0028
[ 453.624641] R10: 000000006dc86f01 R11: ffffea0011b72180 R12:
0000000000000003
[ 453.632619] R13: ffffffff81e1d450 R14: 00000000000000d8 R15:
0000000000000003
[ 453.640598] FS: 0000000000000000(0000) GS:ffff88086f000000(0000)
knlGS:0000000000000000
[ 453.649645] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 453.656069] CR2: 0000000000000030 CR3: 0000000001a6e000 CR4:
00000000001406e0
[ 453.664047] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[ 453.672027] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
0000000000000400
[ 453.680005] Stack:
[ 453.682251] 00000000000000d8 ffff88046267fd08 ffffffff81057965
0000000000000048
[ 453.690567] ffffffff81b43bd8 ffff88086b125358 ffff88086b783ea0
ffff88086b125300
[ 453.698876] ffff88046267fd20 ffffffff8104e3ff 0000000000000000
ffff88046267fd58
[ 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
[ 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
Fix it by assigning the correct pointers to ioapics[i].iomem_res in
ioapic_setup_resources(). Also simplify the function by removing
the redundant 'num' variable.
Signed-off-by: Rui Wang <rui.y.wang@xxxxxxxxx>
---
arch/x86/kernel/apic/io_apic.c | 18 +++++++-----------
1 file changed, 7 insertions(+), 11 deletions(-)
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index f253218..a90b131 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2563,29 +2563,25 @@ static struct resource * __init ioapic_setup_resources(void)
unsigned long n;
struct resource *res;
char *mem;
- int i, num = 0;
+ int i;
- for_each_ioapic(i)
- num++;
- if (num == 0)
+ if (nr_ioapics == 0)
return NULL;
n = IOAPIC_RESOURCE_NAME_SIZE + sizeof(struct resource);
- n *= num;
+ n *= nr_ioapics;
mem = alloc_bootmem(n);
res = (void *)mem;
- mem += sizeof(struct resource) * num;
+ mem += sizeof(struct resource) * nr_ioapics;
- num = 0;
for_each_ioapic(i) {
- res[num].name = mem;
- res[num].flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+ res[i].name = mem;
+ res[i].flags = IORESOURCE_MEM | IORESOURCE_BUSY;
snprintf(mem, IOAPIC_RESOURCE_NAME_SIZE, "IOAPIC %u", i);
mem += IOAPIC_RESOURCE_NAME_SIZE;
- num++;
- ioapics[i].iomem_res = res;
+ ioapics[i].iomem_res = &res[i];
}
ioapic_resources = res;
--
1.8.3.1
--
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