Subject: linux-next: run time warning after merge of the userns tree

From: Stephen Rothwell <[email-masked]>
Date: Tue, 21 Dec 2021 23:16:11 +1100

Hi all,

[I am just guessing at the userns tree.]

My qemu boot test of a powerpc pseries_le_defconfig kernel produced
this warning:

  SLUB: HWalign=128, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
  ftrace: allocating 33453 entries in 13 pages
  ftrace: allocated 13 pages with 3 groups
  trace event string verifier disabled
  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 0 at kernel/sched/core.c:9469 sched_init+0x45c/0x4f4
  Modules linked in:
  CPU: 0 PID: 0 Comm: swapper Not tainted 5.16.0-rc6 #2
  NIP:  c000000002027c98 LR: c000000002027c94 CTR: 0000000000000000
  REGS: c00000000278bb80 TRAP: 0700   Not tainted  (5.16.0-rc6)
  MSR:  8000000002021033 <SF,VEC,ME,IR,DR,RI,LE>  CR: 84000220  XER: 00000000
  CFAR: c00000000016c1fc IRQMASK: 1 
  GPR00: c000000002027c94 c00000000278be20 c00000000278d300 0000000000000001 
  GPR04: c000000000f88788 c000000002865d98 c000000007070680 0000000000000001 
  GPR08: 000000007dae0000 c000000007070630 0000000000000000 0000000000000001 
  GPR12: 0000000000000000 c000000002970000 0000000000000000 0000000000000000 
  GPR16: 0000000002bf00d0 c0000000027c1f38 c00000000017e510 c000000002867f00 
  GPR20: c0000000025306b8 c00000000017b520 c00000000017b200 c0000000028682b8 
  GPR24: 0000000000000400 0000000000000000 c0000000027c2470 c0000000027b3a00 
  GPR28: c0000000021af900 0000000000000800 0000000000000000 c00000007fc8f900 
  NIP [c000000002027c98] sched_init+0x45c/0x4f4
  LR [c000000002027c94] sched_init+0x458/0x4f4
  Call Trace:
  [c00000000278be20] [c000000002027c94] sched_init+0x458/0x4f4 (unreliable)
  [c00000000278bed0] [c000000002004200] start_kernel+0x53c/0x8cc
  [c00000000278bf90] [c00000000000d39c] start_here_common+0x1c/0x600
  Instruction dump:
  90ea0188 f92a0180 3d22fffb 39291890 39490050 7d005028 31080001 7d00512d 
  40c2fff4 e86d0908 4a144499 60000000 <0b030000> a08d0008 e86d0908 4bfff849 
  ---[ end trace 0000000000000000 ]---

Exposed by commit

  40966e316f86 ("kthread: Ensure struct kthread is present for all kthreads")

-- 
Cheers,
Stephen Rothwell