[mainline]Kernel OOPs at migrate_swap_task

[Venkat Rao Bagalkote]

Hello,


IBM CI has reported a kernel oops, while running cpu monitor test [1], 
on the mainline kernel.


[1]: 
https://github.com/avocado-framework-tests/avocado-misc-tests/blob/master/cpu/cpupower_monitor.py


I am still in porcess of doing git bisect, meanwhile, wondering if below 
traces gives any clue.


Traces:


[ 2181.567879] Kernel attempted to read user page (5b0) - exploit 
attempt? (uid: 0)
[ 2181.567913] BUG: Kernel NULL pointer dereference on read at 0x000005b0
[ 2181.567918] Faulting instruction address: 0xc0000000001d4a48
[ 2181.567924] Oops: Kernel access of bad area, sig: 11 [#1]
[ 2181.567929] LE PAGE_SIZE=64K MMU=Radix  SMP NR_CPUS=8192 NUMA pSeries
[ 2181.567936] Modules linked in: dm_mod ext4 crc16 mbcache jbd2 loop 
nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet 
nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nft_chain_nat nf_nat 
nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 bonding tls rfkill ip_set 
nf_tables nfnetlink pseries_rng vmx_crypto fuse xfs sr_mod cdrom sd_mod 
sg ibmvscsi scsi_transport_srp ibmveth [last unloaded: scsi_debug]
[ 2181.567990] CPU: 0 UID: 0 PID: 19 Comm: migration/0 Kdump: loaded Not 
tainted 6.15.0-ge271ed52b344 #1 VOLUNTARY

[ 2181.568003] Stopper: multi_cpu_stop+0x0/0x22c <- migrate_swap+0xe8/0x214
[ 2181.568016] NIP:  c0000000001d4a48 LR: c0000000001d4a3c CTR: 
c0000000001d6864
[ 2181.568021] REGS: c0000000087ffaf0 TRAP: 0300   Not tainted 
(6.15.0-ge271ed52b344)
[ 2181.568026] MSR:  8000000002803033 <SF,VEC,VSX,FP,ME,IR,DR,RI,LE>  
CR: 48004202  XER: 00000000
[ 2181.568038] CFAR: c00000000003a360 DAR: 00000000000005b0 DSISR: 
40000000 IRQMASK: 3
[ 2181.568038] GPR00: c0000000001d4df4 c0000000087ffd90 c000000001648100 
0000000000000003
[ 2181.568038] GPR04: 0000000000000010 0000000000000000 00000941d4c72888 
0000000000000000
[ 2181.568038] GPR08: 00000004fdad0000 0000000000000000 000000000000013a 
0000000000004000
[ 2181.568038] GPR12: c0000004ffd3c780 c000000002ff0000 c0000000001ae2e0 
c0000000040533c0
[ 2181.568038] GPR16: 0000000000000000 0000000000000000 0000000000000000 
0000000000000000
[ 2181.568038] GPR20: 0000000000000000 0000000000000000 0000000000000000 
0000000000000001
[ 2181.568038] GPR24: c000000529930f4c 0000000000000000 c000000529930180 
c000000642c60100
[ 2181.568038] GPR28: c000000642c60ecc c0000013fd68c700 0000000000000010 
c000000642c60100
[ 2181.568088] NIP [c0000000001d4a48] __migrate_swap_task+0x6c/0x1d8
[ 2181.568094] LR [c0000000001d4a3c] __migrate_swap_task+0x60/0x1d8
[ 2181.568100] Call Trace:
[ 2181.568103] [c0000000087ffd90] [c0000000001d4b70] 
__migrate_swap_task+0x194/0x1d8 (unreliable)
[ 2181.568112] [c0000000087ffdc0] [c0000000001d4df4] 
migrate_swap_stop+0x240/0x2b4
[ 2181.568118] [c0000000087ffe20] [c0000000002efc04] 
multi_cpu_stop+0xd8/0x22c
[ 2181.568123] [c0000000087ffe90] [c0000000002ef8e8] 
cpu_stopper_thread+0x158/0x24c
[ 2181.568129] [c0000000087fff40] [c0000000001b93b0] 
smpboot_thread_fn+0x200/0x2c0
[ 2181.568137] [c0000000087fff90] [c0000000001ae40c] kthread+0x134/0x164
[ 2181.568144] [c0000000087fffe0] [c00000000000df98] 
start_kernel_thread+0x14/0x18
[ 2181.568150] Code: 60690001 992d0932 e90d0030 3d2200c2 39290378 
7d49402a 394a0001 7d49412a 4be65771 60000000 60000000 e93f0a70 
<e86905b0> 48426c89 60000000 2c230000
[ 2181.568165] ---[ end trace 0000000000000000 ]---
[ 2181.568687]


If you happen to fix this, please add below tag.


Reported-by: Venkat Rao Bagalkote <venkat88@xxxxxxxxxxxxx>



Regards,

Venkat.