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

From: Stephen Rothwell <[email-masked]>
Date: Fri, 9 Feb 2024 16:06:54 +1100

Hi all,

After merging the mm tree, today's linux-next boot (powerpc
pseries_le_defconfig) failed like this:

numa:   NODE_DATA [mem 0x7ffd8800-0x7ffdffff]
BUG: Kernel NULL pointer dereference at 0x00000030
Faulting instruction address: 0xc00000000045322c
Oops: Kernel access of bad area, sig: 11 [#1]
LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries
Modules linked in:
CPU: 0 PID: 0 Comm: swapper Not tainted 6.8.0-rc3-05899-ga19e02faed6b #1
Hardware name: IBM pSeries (emulated by qemu) POWER8 (raw) 0x4d0200 0xf000004 of:SLOF,HEAD pSeries
NIP:  c00000000045322c LR: c00000000045332c CTR: c0000000000e72c0
REGS: c00000000292f8e0 TRAP: 0380   Not tainted  (6.8.0-rc3-05899-ga19e02faed6b)
MSR:  8000000000001033 <SF,ME,IR,DR,RI,LE>  CR: 48004888  XER: 20000000
CFAR: c000000000453328 IRQMASK: 1 
GPR00: c0000000011d4688 c00000000292fb80 c0000000015c9900 c00000007ffd8800 
GPR04: 000000000000002f 0000000000000001 40066bdea7000015 0000000000000000 
GPR08: 0000000000000000 0000000000000030 0000000000000030 0000000000004000 
GPR12: c00000000292f968 c000000002b60000 0000000080000000 0000000000000004 
GPR16: 0000000000000004 0000000000000060 0000000000000002 00000000017d2358 
GPR20: 0000000000000000 0000000000000000 0000000008000000 c00c000000004000 
GPR24: 0000000000000000 c0000000029d0260 0000000000000000 0000000000000000 
GPR28: c00c000000000000 0000000000000000 0000000000004000 0000000000000001 
NIP [c00000000045322c] __mod_node_page_state+0x30/0x100
LR [c00000000045332c] mod_node_page_state+0x30/0x50
Call Trace:
[c00000000292fb80] [c00c000000000000] 0xc00c000000000000 (unreliable)
[c00000000292fbb0] [c0000000011d4688] __populate_section_memmap+0x10c/0x1b4
[c00000000292fc20] [c000000002060e20] sparse_init_nid+0x210/0x7e0
[c00000000292fcf0] [c0000000020618d4] sparse_init+0x3c4/0x5f0
[c00000000292fdc0] [c00000000202185c] initmem_init+0x1d4/0x278
[c00000000292fea0] [c00000000200d774] setup_arch+0x4fc/0x618
[c00000000292ff30] [c000000002004ee0] start_kernel+0x9c/0x8cc
[c00000000292ffe0] [c00000000000e99c] start_here_common+0x1c/0x20
Code: 3c4c0117 38426704 60000000 60000000 e9037600 3924fffb 28090001 39480001 7d4a2214 40810040 e8ed0030 7d495378 <7d2748ae> 7d0740ae 7d290774 7d080774 
---[ end trace 0000000000000000 ]---

Kernel panic - not syncing: Attempted to kill the idle task!

Bisected to commit

  a1a91b2f3883 ("mm: report per-page metadata information")

From the mm-unstable branch of the mm tree.

I reverted that commit for today.
-- 
Cheers,
Stephen Rothwell