Hi.
We hit this x86 math_error warning in Linux kernel 3.10.
------------[ cut here ]------------
WARNING: at arch/x86/include/asm/fpu-internal.h:524 math_error+0xd1/0x219()
Modules linked in: cls_basic act_mirred cls_u32 veth sch_ingress
netconsole configfs ipv6 dm_multipath scsi_dh video sbs sbshc hed
acpi_pad acpi_ipmi acpi_i2c parport_pc lp parport tcp_diag inet_diag
ipmi_si ipmi_devintf ipmi_msghandler dell_rbu sg iTCO_wdt
iTCO_vendor_support dcdbas igb i2c_algo_bit ptp pps_core shpchp
lpc_ich i2c_i801 mfd_core i2c_core ioatdma dca i7core_edac edac_core
microcode freq_table mperf ahci libahci libata sd_mod scsi_mod
CPU: 2 PID: 53182 Comm: java Not tainted 3.10.50 #1
0000000000000000 ffff8808e1f5be38 ffffffff8146cb74 ffff8808e1f5be70
ffffffff8103cbf9 0000000000000000 ffff88090b2c9730 ffff8808e1f5bf58
0000000000000010 0000000000000000 ffff8808e1f5be80 ffffffff8103ccbf
Call Trace:
[<ffffffff8146cb74>] dump_stack+0x19/0x1b
[<ffffffff8103cbf9>] warn_slowpath_common+0x65/0x7d
[<ffffffff8103ccbf>] warn_slowpath_null+0x1a/0x1c
[<ffffffff8100317b>] math_error+0xd1/0x219
[<ffffffff81007f6c>] ? read_tsc+0x9/0x19
[<ffffffff8107bab8>] ? timekeeping_get_ns.constprop.10+0x11/0x36
[<ffffffff8107bf32>] ? ktime_get+0x68/0x76
[<ffffffff81007f6c>] ? read_tsc+0x9/0x19
[<ffffffff8107bab8>] ? timekeeping_get_ns.constprop.10+0x11/0x36
[<ffffffff810032d6>] do_coprocessor_error+0x13/0x15
[<ffffffff81478a38>] coprocessor_error+0x18/0x20
---[ end trace 3e4a6532a67ba6d3 ]---
Here are the CPU flags:
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe
syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts
rep_good nopl xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64
monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm pcid dca sse4_1
sse4_2 popcnt aes lahf_lm ida arat epb dtherm tpr_shadow vnmi
flexpriority ept vpid
arch/x86/include/asm/fpu-internal.h
519 /*
520 * These disable preemption on their own and are safe
521 */
522 static inline void save_init_fpu(struct task_struct *tsk)
523 {
524 WARN_ON_ONCE(!__thread_has_fpu(tsk));
525
526 if (use_eager_fpu()) {
527 __save_fpu(tsk);
528 return;
529 }
530
531 preempt_disable();
532 __save_init_fpu(tsk);
533 __thread_fpu_end(tsk);
534 preempt_enable();
535 }
Cheers,
Vinson
On Fri, Nov 14, 2014 at 12:19:16PM -0800, Vinson Lee wrote:
> Hi.
>
> We hit this x86 math_error warning in Linux kernel 3.10.
>
> ------------[ cut here ]------------
> WARNING: at arch/x86/include/asm/fpu-internal.h:524 math_error+0xd1/0x219()
> Modules linked in: cls_basic act_mirred cls_u32 veth sch_ingress
> netconsole configfs ipv6 dm_multipath scsi_dh video sbs sbshc hed
> acpi_pad acpi_ipmi acpi_i2c parport_pc lp parport tcp_diag inet_diag
> ipmi_si ipmi_devintf ipmi_msghandler dell_rbu sg iTCO_wdt
> iTCO_vendor_support dcdbas igb i2c_algo_bit ptp pps_core shpchp
> lpc_ich i2c_i801 mfd_core i2c_core ioatdma dca i7core_edac edac_core
> microcode freq_table mperf ahci libahci libata sd_mod scsi_mod
> CPU: 2 PID: 53182 Comm: java Not tainted 3.10.50 #1
> 0000000000000000 ffff8808e1f5be38 ffffffff8146cb74 ffff8808e1f5be70
> ffffffff8103cbf9 0000000000000000 ffff88090b2c9730 ffff8808e1f5bf58
> 0000000000000010 0000000000000000 ffff8808e1f5be80 ffffffff8103ccbf
> Call Trace:
> [<ffffffff8146cb74>] dump_stack+0x19/0x1b
> [<ffffffff8103cbf9>] warn_slowpath_common+0x65/0x7d
> [<ffffffff8103ccbf>] warn_slowpath_null+0x1a/0x1c
> [<ffffffff8100317b>] math_error+0xd1/0x219
> [<ffffffff81007f6c>] ? read_tsc+0x9/0x19
> [<ffffffff8107bab8>] ? timekeeping_get_ns.constprop.10+0x11/0x36
> [<ffffffff8107bf32>] ? ktime_get+0x68/0x76
> [<ffffffff81007f6c>] ? read_tsc+0x9/0x19
> [<ffffffff8107bab8>] ? timekeeping_get_ns.constprop.10+0x11/0x36
> [<ffffffff810032d6>] do_coprocessor_error+0x13/0x15
> [<ffffffff81478a38>] coprocessor_error+0x18/0x20
> ---[ end trace 3e4a6532a67ba6d3 ]---
AFAICT, you're getting an FPU exception for a task which hasn't used the
FPU or current is somehow pointing to the wrong task.
Can you trigger this with the latest kernel too, i.e., say, 3.18-rc4?
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
On Fri, 14 Nov 2014, Borislav Petkov wrote:
> On Fri, Nov 14, 2014 at 12:19:16PM -0800, Vinson Lee wrote:
> > Hi.
> >
> > We hit this x86 math_error warning in Linux kernel 3.10.
> >
> > ------------[ cut here ]------------
> > WARNING: at arch/x86/include/asm/fpu-internal.h:524 math_error+0xd1/0x219()
> > Modules linked in: cls_basic act_mirred cls_u32 veth sch_ingress
> > netconsole configfs ipv6 dm_multipath scsi_dh video sbs sbshc hed
> > acpi_pad acpi_ipmi acpi_i2c parport_pc lp parport tcp_diag inet_diag
> > ipmi_si ipmi_devintf ipmi_msghandler dell_rbu sg iTCO_wdt
> > iTCO_vendor_support dcdbas igb i2c_algo_bit ptp pps_core shpchp
> > lpc_ich i2c_i801 mfd_core i2c_core ioatdma dca i7core_edac edac_core
> > microcode freq_table mperf ahci libahci libata sd_mod scsi_mod
> > CPU: 2 PID: 53182 Comm: java Not tainted 3.10.50 #1
> > 0000000000000000 ffff8808e1f5be38 ffffffff8146cb74 ffff8808e1f5be70
> > ffffffff8103cbf9 0000000000000000 ffff88090b2c9730 ffff8808e1f5bf58
> > 0000000000000010 0000000000000000 ffff8808e1f5be80 ffffffff8103ccbf
> > Call Trace:
> > [<ffffffff8146cb74>] dump_stack+0x19/0x1b
> > [<ffffffff8103cbf9>] warn_slowpath_common+0x65/0x7d
> > [<ffffffff8103ccbf>] warn_slowpath_null+0x1a/0x1c
> > [<ffffffff8100317b>] math_error+0xd1/0x219
> > [<ffffffff81007f6c>] ? read_tsc+0x9/0x19
> > [<ffffffff8107bab8>] ? timekeeping_get_ns.constprop.10+0x11/0x36
> > [<ffffffff8107bf32>] ? ktime_get+0x68/0x76
> > [<ffffffff81007f6c>] ? read_tsc+0x9/0x19
> > [<ffffffff8107bab8>] ? timekeeping_get_ns.constprop.10+0x11/0x36
> > [<ffffffff810032d6>] do_coprocessor_error+0x13/0x15
> > [<ffffffff81478a38>] coprocessor_error+0x18/0x20
> > ---[ end trace 3e4a6532a67ba6d3 ]---
>
> AFAICT, you're getting an FPU exception for a task which hasn't used the
> FPU or current is somehow pointing to the wrong task.
>
> Can you trigger this with the latest kernel too, i.e., say, 3.18-rc4?
Also Vinson forgot to mention HOW that is triggered. Without an
explanation of the reproducer it's hard to tell what's going wrong.
Thanks,
tglx
On Fri, Nov 14, 2014 at 12:39 PM, Thomas Gleixner <[email protected]> wrote:
> On Fri, 14 Nov 2014, Borislav Petkov wrote:
>> On Fri, Nov 14, 2014 at 12:19:16PM -0800, Vinson Lee wrote:
>> > Hi.
>> >
>> > We hit this x86 math_error warning in Linux kernel 3.10.
>> >
>> > ------------[ cut here ]------------
>> > WARNING: at arch/x86/include/asm/fpu-internal.h:524 math_error+0xd1/0x219()
>> > Modules linked in: cls_basic act_mirred cls_u32 veth sch_ingress
>> > netconsole configfs ipv6 dm_multipath scsi_dh video sbs sbshc hed
>> > acpi_pad acpi_ipmi acpi_i2c parport_pc lp parport tcp_diag inet_diag
>> > ipmi_si ipmi_devintf ipmi_msghandler dell_rbu sg iTCO_wdt
>> > iTCO_vendor_support dcdbas igb i2c_algo_bit ptp pps_core shpchp
>> > lpc_ich i2c_i801 mfd_core i2c_core ioatdma dca i7core_edac edac_core
>> > microcode freq_table mperf ahci libahci libata sd_mod scsi_mod
>> > CPU: 2 PID: 53182 Comm: java Not tainted 3.10.50 #1
>> > 0000000000000000 ffff8808e1f5be38 ffffffff8146cb74 ffff8808e1f5be70
>> > ffffffff8103cbf9 0000000000000000 ffff88090b2c9730 ffff8808e1f5bf58
>> > 0000000000000010 0000000000000000 ffff8808e1f5be80 ffffffff8103ccbf
>> > Call Trace:
>> > [<ffffffff8146cb74>] dump_stack+0x19/0x1b
>> > [<ffffffff8103cbf9>] warn_slowpath_common+0x65/0x7d
>> > [<ffffffff8103ccbf>] warn_slowpath_null+0x1a/0x1c
>> > [<ffffffff8100317b>] math_error+0xd1/0x219
>> > [<ffffffff81007f6c>] ? read_tsc+0x9/0x19
>> > [<ffffffff8107bab8>] ? timekeeping_get_ns.constprop.10+0x11/0x36
>> > [<ffffffff8107bf32>] ? ktime_get+0x68/0x76
>> > [<ffffffff81007f6c>] ? read_tsc+0x9/0x19
>> > [<ffffffff8107bab8>] ? timekeeping_get_ns.constprop.10+0x11/0x36
>> > [<ffffffff810032d6>] do_coprocessor_error+0x13/0x15
>> > [<ffffffff81478a38>] coprocessor_error+0x18/0x20
>> > ---[ end trace 3e4a6532a67ba6d3 ]---
>>
>> AFAICT, you're getting an FPU exception for a task which hasn't used the
>> FPU or current is somehow pointing to the wrong task.
>>
>> Can you trigger this with the latest kernel too, i.e., say, 3.18-rc4?
>
> Also Vinson forgot to mention HOW that is triggered. Without an
> explanation of the reproducer it's hard to tell what's going wrong.
>
> Thanks,
>
> tglx
Thanks for the quick responses. This is an infrequent warning. We have
yet to reliably reproduce it or narrow down to a test case.
Thanks.
Vinson