| Message ID | 1465284073-354-3-git-send-email-rui.y.wang@intel.com |
|---|---|
| State | Superseded |
| Headers | show |
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-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tuesday, June 7, 2016 5:17 PM, Thomas Gleixner wrote: > On Tue, 7 Jun 2016, Rui Wang wrote: > > 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. Hi Thomas, Yes exactly. I'll send a v2. Thanks Rui -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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;
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@intel.com> --- arch/x86/kernel/apic/io_apic.c | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-)