Subject: Re: [BUG] PowerNV crash with 4.4.0-rc8 at sched_init_numa (related to commit c118baf80256)

From: Jan Stancek <[email-masked]>
Date: Sun, 10 Jan 2016 04:25:20 -0500 (EST)

----- Original Message -----
> From: "Raghavendra K T" <[email-masked]>
> To: "Jan Stancek" <[email-masked]>
> Cc: [email-masked], [email-masked], [email-masked], [email-masked],
> [email-masked], [email-masked], [email-masked], [email-masked], "grant likely"
> <[email-masked]>, [email-masked], "Steve Best" <[email-masked]>, "Gustavo Duarte"
> <[email-masked]>, "Thomas Huth" <[email-masked]>
> Sent: Sunday, 10 January, 2016 7:47:31 AM
> Subject: Re: [BUG] PowerNV crash with 4.4.0-rc8 at sched_init_numa (related to commit c118baf80256)
> 
> On 01/10/2016 04:33 AM, Jan Stancek wrote:
> > Hi,
> >
> > I'm seeing bare metal ppc64le system crashing early during boot
> > with latest upstream kernel (4.4.0-rc8):
> >
> 
> Hi Jan,
> Thanks for reporting. Let me try to reproduce the issue.
> 
> (Between if you think there is anything special in the .config
> that I need for testing .. please share).

Config has many debug options turned on, so my guess was SCHED_DEBUG.
I've uploaded my config here:
  http://jan.stancek.eu/tmp/powernv_crash_sched_init_numa/config-powernv-crash-4.4.0-rc8

Regards,
Jan

> 
> - Raghu
> 
> > # git describe
> > v4.4-rc8-96-g751e5f5
> >
> > [    0.625451] Unable to handle kernel paging request for data at address
> > 0x00000000
> > [    0.625586] Faulting instruction address: 0xc0000000004ae000
> > [    0.625698] Oops: Kernel access of bad area, sig: 11 [#1]
> > [    0.625789] SMP NR_CPUS=2048 NUMA PowerNV
> > [    0.625879] Modules linked in:
> > [    0.625973] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.4.0-rc8+ #6
> > [    0.626087] task: c000002ff4300000 ti: c000002ff6084000 task.ti:
> > c000002ff6084000
> > [    0.626224] NIP: c0000000004ae000 LR: c00000000090b9e4 CTR:
> > 0000000000000003
> > [    0.626361] REGS: c000002ff6087930 TRAP: 0300   Not tainted
> > (4.4.0-rc8+)
> > [    0.626475] MSR: 9000000100009033 <SF,HV,EE,ME,IR,DR,RI,LE>  CR:
> > 48002044  XER: 20000000
> > [    0.626808] CFAR: c000000000008468 DAR: 0000000000000000 DSISR: 40000000
> > SOFTE: 1
> > GPR00: c00000000090b9ac c000002ff6087bb0 c000000001700900 c000003ff229e080
> > GPR04: c000003ff229e080 0000000000000000 0000000000000003 0000000000000001
> > GPR08: 0000000000000000 0000000000000000 0000000000000010 9000000100001003
> > GPR12: 0000000000002200 c00000000fb40000 c00000000000bd68 0000000000000002
> > GPR16: 0000000000000028 c000000000b25940 c00000000173ffa4 0000000000000000
> > GPR20: c000000000b259d8 c000000000b259e0 c000000000b259e8 0000000000000000
> > GPR24: c000003ff229e080 0000000000000000 c00000000189b180 0000000000000000
> > GPR28: 0000000000000000 c000000001740a94 0000000000000002 0000000000000002
> > [    0.627925] NIP [c0000000004ae000] __bitmap_or+0x30/0x50
> > [    0.627973] LR [c00000000090b9e4] sched_init_numa+0x440/0x7c8
> > [    0.628030] Call Trace:
> > [    0.628054] [c000002ff6087bb0] [c00000000090b9ac]
> > sched_init_numa+0x408/0x7c8 (unreliable)
> > [    0.628136] [c000002ff6087ca0] [c000000000c60718]
> > sched_init_smp+0x60/0x238
> > [    0.628206] [c000002ff6087d00] [c000000000c44294]
> > kernel_init_freeable+0x1fc/0x3b4
> > [    0.628286] [c000002ff6087dc0] [c00000000000bd84] kernel_init+0x24/0x140
> > [    0.628356] [c000002ff6087e30] [c000000000009544]
> > ret_from_kernel_thread+0x5c/0x98
> > [    0.628435] Instruction dump:
> > [    0.628470] 38c6003f 78c9d183 4d820020 38c9ffff 39200000 78c60020
> > 38c60001 7cc903a6
> > [    0.628587] 60000000 60000000 60000000 60420000 <7d05482a> 7d44482a
> > 7d0a5378 7d43492a
> > [    0.628711] ---[ end trace b423f3e02b333fbf ]---
> > [    0.628757]
> > [    2.628822] Kernel panic - not syncing: Fatal exception
> > [    2.628969] Rebooting in 10 seconds..[    0.000000] OPAL V3 detected !
> >
> > # numactl -H
> > available: 4 nodes (0-1,16-17)
> > node 0 cpus: 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
> > 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39
> > node 0 size: 64941 MB
> > node 0 free: 64210 MB
> > node 1 cpus: 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60
> > 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79
> > node 1 size: 65456 MB
> > node 1 free: 62424 MB
> > node 16 cpus: 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99
> > 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117
> > 118 119
> > node 16 size: 65457 MB
> > node 16 free: 65258 MB
> > node 17 cpus: 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134
> > 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151
> > node 17 size: 65186 MB
> > node 17 free: 65001 MB
> > node distances:
> > node   0   1  16  17
> >    0:  10  20  40  40
> >    1:  20  10  40  40
> >   16:  40  40  10  20
> >   17:  40  40  20  10
> >
> > The crash goes away if I revert following commit:
> >    commit c118baf802562688d46e6002f2b5fe66b947da21
> >    Author: Raghavendra K T <[email-masked]>
> >    Date:   Thu Nov 5 18:46:29 2015 -0800
> >      arch/powerpc/mm/numa.c: do not allocate bootmem memory for non
> >      existing nodes
> >
> > Regards,
> > Jan
> >
> >
> >
> 
>