Subject: linux-next: boot warning from the final tree

From: Stephen Rothwell <[email-masked]>
Date: Mon, 17 Nov 2025 20:22:14 +1100

Hi all,

Today's linux-next qemu boot (powerpc pseries_le_defconfig) produced
this warning:

  ftrace: allocating 48915 entries in 288 pages
  ftrace: allocated 287 pages with 6 groups
  ------------[ cut here ]------------
  DEBUG_LOCKS_WARN_ON(lock->magic != lock)
  WARNING: kernel/locking/mutex.c:156 at mutex_lock+0xcc/0x100, CPU#0: swapper/0/0
  Modules linked in:
  CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.18.0-rc6-09359-g921087e37218 #1 VOLUNTARY 
  Hardware name: IBM pSeries (emulated by qemu) POWER9 (architected) 0x4e1202 0xf000005 of:SLOF,HEAD hv:linux,kvm pSeries
  NIP:  c00000000148041c LR: c000000001480418 CTR: 0000000000000000
  REGS: c000000002957a10 TRAP: 0700   Not tainted  (6.18.0-rc6-09359-g921087e37218)
  MSR:  8000000002021033 <SF,VEC,ME,IR,DR,RI,LE>  CR: 24022240  XER: 00000000
  CFAR: c00000000021123c IRQMASK: 3 
  GPR00: c000000001480418 c000000002957cb0 c000000001a3a100 0000000000000028 
  GPR04: 00000000ffffe04a c0000000026abe88 0000000000000001 000000000000004b 
  GPR08: c0000000026abd28 0000000000000000 0000000000000000 0000000044022240 
  GPR12: 0000000000000000 c000000002ae9000 0000000000000000 0000000001bff430 
  GPR16: 000000007e68f070 c00000007f79c480 c000000002969160 c000000002a0f5d8 
  GPR20: c0000000026a1138 c0000000026a1120 0000000000000000 c0000000019541b8 
  GPR24: c00000000218a480 c00000000296e1d0 000000007d612000 c00000000380be10 
  GPR28: c00000000380be20 c00000000380be00 c000000002640100 c00000000380be20 
  NIP [c00000000148041c] mutex_lock+0xcc/0x100
  LR [c000000001480418] mutex_lock+0xc8/0x100
  Call Trace:
  [c000000002957cb0] [c000000001480418] mutex_lock+0xc8/0x100 (unreliable)
  [c000000002957d20] [c00000000024a60c] alloc_workqueue_noprof+0x38c/0x8ec
  [c000000002957e00] [c00000000203018c] workqueue_init_early+0x4d8/0x6ec
  [c000000002957f30] [c000000002004448] start_kernel+0x74c/0xa4c
  [c000000002957fe0] [c00000000000e99c] start_here_common+0x1c/0x20
  Code: 4182ffb4 3d2200f3 392971e4 81290000 2c090000 4082ffa0 3c82ffe0 3c62ffe0 3884bfe0 3863bf68 4ad90d45 60000000 <0fe00000> 4bffff80 60000000 60000000 
  ---[ end trace 0000000000000000 ]---
  rcu: Hierarchical RCU implementation.

I have no idea what caused this.

-- 
Cheers,
Stephen Rothwell