Re: [linux-next20251118] BUG: Kernel NULL pointer dereference

[Shrikanth Hegde]

On 11/18/25 12:10 PM, Venkat Rao Bagalkote wrote:
> Greetings!!
>
>
> IBM CI has reported a boot crash while booting with linux-next2025118 
> kernel.
>
>
> Traces:
>
>
> [    0.116026] audit: type=2000 audit(1763602256.110:1): 
> state=initialized audit_enabled=0 res=1
> [    0.116282] thermal_sys: Registered thermal governor 'fair_share'
> [    0.116284] thermal_sys: Registered thermal governor 'step_wise'
> [    0.120228] BUG: Kernel NULL pointer dereference at 0x00000000
> [    0.120236] Faulting instruction address: 0xc0000000002b08a4
> [    0.120241] Oops: Kernel access of bad area, sig: 11 [#3]
> [    0.120245] LE PAGE_SIZE=64K MMU=Hash  SMP NR_CPUS=8192 NUMA pSeries
> [    0.120252] Modules linked in:
> [    0.120257] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G   D       
>   6.18.0-rc6-next-20251118 #1 VOLUNTARY
> [    0.120265] Tainted: [D]=DIE
> [    0.120268] Hardware name: IBM,8375-42A POWER9 (architected) 0x4e0202 
> 0xf000005 of:IBM,FW950.80 (VL950_131) hv:phyp pSeries
> [    0.120273] NIP:  c0000000002b08a4 LR: c0000000002b04a4 CTR: 
> 0000000000000000
> [    0.120278] REGS: c0000009fffffaa0 TRAP: 0380   Tainted: G D     
> (6.18.0-rc6-next-20251118)
> [    0.120284] MSR:  8000000000009033 <SF,EE,ME,IR,DR,RI,LE>  CR: 
> 48002828  XER: 20040006
> [    0.120296] CFAR: c0000000002b04bc IRQMASK: 0
> [    0.120296] GPR00: c0000000002b04a4 c0000009fffffd40 c000000001e58100 
> 0000000000000001
> [    0.120296] GPR04: c000000002d68100 0000000000000007 0000000000000000 
> 0000000000000001
> [    0.120296] GPR08: c000000005331e78 0000000000000400 c000000002d68100 
> 0000000000000000
> [    0.120296] GPR12: 0000000000000000 c000000002f90000 0000000000000000 
> c0000009fffffe94
> [    0.120296] GPR16: 0000000000000000 c000000002cadb00 0000000000000000 
> c000000003675e00
> [    0.120296] GPR20: 0000000000000000 0000000000000000 0000000000000001 
> 00000000ffff8add
> [    0.120296] GPR24: 0000000000000001 c00000000cacaa00 c000000002c72b00 
> 0000000000000000
> [    0.120296] GPR28: c0000009fffffdb8 0000000000000000 c0000009e941b800 
> c0000009e941b800
> [    0.120353] NIP [c0000000002b08a4] sched_balance_rq+0x504/0x8b0
> [    0.120361] LR [c0000000002b04a4] sched_balance_rq+0x104/0x8b0


This should be fixed by this.
https://lore.kernel.org/lkml/176339661932.498.15491008222212450109.tip-bot2@tip-bot2/

Can you rebase tip/sched/core to latest and try?