Subject: Re: linux-next: boot failure after merge of the akpm tree

From: Luis Chamberlain <[email-masked]>
Date: Tue, 30 Nov 2021 08:21:52 -0800

On Tue, Nov 30, 2021 at 06:46:22PM +1100, Stephen Rothwell wrote:
> Hi all,
> 
> After merging the akpm tree, today's linux-next boot test (powerpc
> pseries_le_defconfig) failed like this:
> 
> [    0.025828][    T0] pid_max: default: 32768 minimum: 301
> [    0.028445][    T0] Mount-cache hash table entries: 8192 (order: 0, 65536 bytes, linear)
> [    0.028636][    T0] Mountpoint-cache hash table entries: 8192 (order: 0, 65536 bytes, linear)
> [    0.055344][    T0] BUG: Unable to handle kernel data access on write at 0x2000000b7
> [    0.056649][    T0] Faulting instruction address: 0xc00000000057435c
> [    0.057458][    T0] Oops: Kernel access of bad area, sig: 11 [#1]
> [    0.057734][    T0] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
> [    0.058250][    T0] Modules linked in:
> [    0.058816][    T0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.16.0-rc3 #2
> [    0.059410][    T0] NIP:  c00000000057435c LR: c000000000577f54 CTR: 0000000000000003
> [    0.059608][    T0] REGS: c000000002787a80 TRAP: 0380   Not tainted  (5.16.0-rc3)
> [    0.059999][    T0] MSR:  8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE>  CR: 44000288  XER: 20000000
> [    0.060654][    T0] CFAR: c000000000574464 IRQMASK: 0 
> [    0.060654][    T0] GPR00: c000000000577f54 c000000002787d20 c000000002788500 c00000000252d5e8 
> [    0.060654][    T0] GPR04: c000000000e42500 c00000000252d5e8 0000000000000000 c0000000073a02c9 
> [    0.060654][    T0] GPR08: c000000000e42380 c000000000f89d48 c00000000274f700 ffffffffffffffff 
> [    0.060654][    T0] GPR12: 0000000000000000 c000000002970000 0000000000000000 0000000000000000 
> [    0.060654][    T0] GPR16: 0000000002bf00d0 000000000135bfd8 0000000000000000 0000000000000000 
> [    0.060654][    T0] GPR20: c00000000252d6e8 c00000000252d740 0000000000000006 0000000000000000 
> [    0.060654][    T0] GPR24: 0000000000000000 0000000000000002 c000000002662eb8 c00000000252d5e8 
> [    0.060654][    T0] GPR28: 00000002000000b7 c000000001004108 0000000000000000 c00000000252d5c0 
> [    0.062938][    T0] NIP [c00000000057435c] count_subheaders.part.0+0x9c/0x2b0
> [    0.064395][    T0] LR [c000000000577f54] __register_sysctl_paths+0x64/0x320
> [    0.065201][    T0] Call Trace:
> [    0.065521][    T0] [c000000002787dc0] [c000000000577f54] __register_sysctl_paths+0x64/0x320
> [    0.065960][    T0] [c000000002787e40] [c0000000005782a4] __register_sysctl_base+0x34/0x50
> [    0.066570][    T0] [c000000002787e60] [c0000000020259bc] sysctl_init_bases+0x34/0x74
> [    0.066960][    T0] [c000000002787e90] [c000000002041744] proc_sys_init+0x54/0x68
> [    0.067306][    T0] [c000000002787eb0] [c0000000020410dc] proc_root_init+0xb8/0xdc
> [    0.067763][    T0] [c000000002787ed0] [c0000000020044fc] start_kernel+0x838/0x8cc
> [    0.068171][    T0] [c000000002787f90] [c00000000000d39c] start_here_common+0x1c/0x600
> [    0.068782][    T0] Instruction dump:
> [    0.069295][    T0] f821ff61 eab40018 2c350000 418201c8 e9350000 2c290000 4182020c 3b000000 
> [    0.069694][    T0] 3a600000 eb950018 2c3c0000 41820198 <e93c0000> 2c290000 418201dc 3b200000 
> [    0.071747][    T0] ---[ end trace df5d37c8b563422a ]---
> [    0.071967][    T0] 
> [    1.073058][    T0] Kernel panic - not syncing: Attempted to kill the idle task!
> 
> Bisected to commit
> 
>   f00ff38c1dfa ("sysctl: add and use base directory declarer and registration helper")
> 
> I have reverted that complete 6 patch series for today.

I'll be trying to reproduce and fix, thanks for the report!

  Luis