Re: [PowerPC][linux-next-6.11-rc7-20240910] Kernel Warnings at kernel/jump_label.c:266

[Michael Ellerman]

Venkat Rao Bagalkote <venkat88@xxxxxxxxxxxxxxxxxx> writes:
> Greetings!!!
>
> I am observing kernel warnings while booting with
> linux-next-6.11-rc7-20240910 kernel. Below are the warnings.
>
> [   63.613506] WARNING: CPU: 20 PID: 214 at kernel/jump_label.c:266 static_key_dec+0x78/0x8c
> [   63.613518] Modules linked in: ext4 mbcache jbd2 dm_service_time sd_mod sg ibmvfc mlx5_core ibmvnic scsi_transport_fc ibmveth mlxfw psample dm_multipath dm_mirror dm_region_hash dm_log dm_mod fuse
> [   63.613542] CPU: 20 UID: 0 PID: 214 Comm: kworker/20:1 Not tainted 6.11.0-rc7-next-20240910-auto #1
> [   63.613549] Hardware name: IBM,9080-HEX POWER10 (architected) 0x800200 0xf000006 of:IBM,FW1060.00 (NH1060_016) hv:phyp pSeries
> [   63.613556] Workqueue: cgroup_destroy css_free_rwork_fn
> [   63.613563] NIP:  c00000000048ca20 LR: c00000000048d060 CTR: c0000000005cb330
> [   63.613568] REGS: c00000005a1afa80 TRAP: 0700   Not tainted (6.11.0-rc7-next-20240910-auto)
> [   63.613573] MSR:  800000000282b033 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI,LE>  CR: 24000884  XER: 20040001
> [   63.613586] CFAR: c00000000048c9cc IRQMASK: 0
> [   63.613586] GPR00: c00000000048d060 c00000005a1afd20 c0000000015f4300 c000000002faa440
> [   63.613586] GPR04: 0000000000000001 000000000000009e c0000000084bae00 000000000000009d
> [   63.613586] GPR08: 0000000000000000 0000000000000000 ffffffffffffffff c00000005b852780
> [   63.613586] GPR12: c0000000005cb330 c000000c7db7df00 c0000000001a779c c0000000084b27c0
> [   63.613586] GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
> [   63.613586] GPR20: c000000c7b914300 c000000002de73c8 c0000000027b07a8 fffffffffffffef7
> [   63.613586] GPR24: 0000000000000402 c00000005b852780 c000000008eabc05 0000000000000010
> [   63.613586] GPR28: c000000002d2fac0 c00000000e9d6000 c000000070444000 c000000002faa440
> [   63.613633] NIP [c00000000048ca20] static_key_dec+0x78/0x8c
> [   63.613639] LR [c00000000048d060] __static_key_slow_dec_cpuslocked+0x38/0xb4
> [   63.613645] Call Trace:
> [   63.613647] [c00000005a1afd20] [c00000005a1afd50] 0xc00000005a1afd50 (unreliable)
> [   63.613653] [c00000005a1afd50] [c00000000048d124] static_key_slow_dec+0x48/0xb0
> [   63.613660] [c00000005a1afdc0] [c0000000005cb40c] mem_cgroup_css_free+0xdc/0x104
> [   63.613667] [c00000005a1afdf0] [c0000000002c4d58] css_free_rwork_fn+0x70/0x394
> [   63.613673] [c00000005a1afe40] [c00000000019a7dc] process_one_work+0x1fc/0x4dc
> [   63.613680] [c00000005a1afef0] [c00000000019b73c] worker_thread+0x340/0x504
> [   63.613686] [c00000005a1aff90] [c0000000001a78cc] kthread+0x138/0x140
> [   63.613691] [c00000005a1affe0] [c00000000000df98] start_kernel_thread+0x14/0x18
> [   63.613697] Code: 7c0004ac 7c074800 40820018 38600001 5463063e 4e800020 60000000 60000000 7ce93b78 4bffffa4 60000000 60000000 <0fe00000> 38600001 7c60189e 5463063e
> [   63.613711] ---[ end trace 0000000000000000 ]---
>
> Issue is introduced by the commit: de752774f38bb766941ed1bf910ba5a9f6cc6bf7

Which was:

  de752774f38b ("jump_label: Fix static_key_slow_dec() yet again")

And was already reported:

  https://lore.kernel.org/all/202409082005.393050e2-oliver.sang@xxxxxxxxx/
  https://lore.kernel.org/all/20240910111111.2591-1-spasswolf@xxxxxx

In today's linux-next (20240911) it has become:

  1d7f856c2ca4 ("jump_label: Fix static_key_slow_dec() yet again")

Can you test if the bug is fixed in today's linux-next?

cheers