Re: [mainline] powerpc/TM: Unexpected TM Bad Thing during core dump on POWER9 (7.1‑rc1)

[Venkat <venkat88@linux.ibm.com>]

> On 15 May 2026, at 10:59 AM, Venkat Rao Bagalkote <venkat88@linux.ibm.com> wrote:
> 
> 
> On 28/04/26 5:48 pm, Venkat Rao Bagalkote wrote:
>> Greetings!!
>> 
>> IBM CI has reported a kernel crash while running selftests/powerpc/signal on a POWER9 pSeries system.
>> 
>> I attempted to reproduce this issue manually, but was not successful so far.
> 
> I’m now able to reproduce this issue reliably and consistently. The reproduction steps are simple:
> 
> Run selftests/powerpc/signal
> 

This issue is still present in 7.3-rc2 as well. Please let me know, if it’s invalid bug, I will make appropriate changes to my CI set up.

This is blocking for me.

Traces:

[12689.799298] Unexpected TM Bad Thing exception at c00000000000dbac (msr 0x8000000302a03031) tm_scratch=800000010280b033
[12689.799318] Oops: Unrecoverable exception, sig: 6 [#1]
[12689.799323] LE PAGE_SIZE=64K MMU=Hash  SMP NR_CPUS=8192 NUMA pSeries
[12689.799330] Modules linked in: nvram(E) rpadlpar_io(E) rpaphp(E) bonding(E) tls(E) rfkill(E) nft_fib_inet(E) nft_fib_ipv4(E) nft_fib_ipv6(E) nft_fib(E) nft_reject_inet(E) nf_reject_ipv4(E) nf_reject_ipv6(E) nft_reject(E) nft_ct(E) nft_chain_nat(E) hvcs(E) hvcserver(E) pseries_rng(E) sg(E) vmx_crypto(E) drm(E) fuse(E) drm_panel_orientation_quirks(E) xfs(E) nvme_tcp(E) nvme_fabrics(E) nvme_core(E) sr_mod(E) sd_mod(E) cdrom(E) ibmvscsi(E) ibmveth(E) scsi_transport_srp(E) dm_mirror(E) dm_region_hash(E) dm_log(E) dm_mod(E)
[12689.799397] CPU: 0 UID: 0 PID: 1159004 Comm: sigfuz Tainted: G            E       7.3.0-rc2-next-20260907 #1 PREEMPT 
[12689.799405] Tainted: [E]=UNSIGNED_MODULE
[12689.799408] Hardware name: IBM,8375-42A POWER9 (architected) 0x4e0202 0xf000005 of:IBM,FW950.80 (VL950_131) hv:phyp pSeries
[12689.799414] NIP:  c00000000000dbac LR: c0000000008657f0 CTR: 0000000000000046
[12689.799419] REGS: c00000002e86fd60 TRAP: 0700   Tainted: G            E        (7.3.0-rc2-next-20260907)
[12689.799425] MSR:  8000000302a03031 <SF,VEC,VSX,FP,ME,IR,DR,LE,TM[SE]>  CR: 48004840  XER: 00000000
[12689.799444] CFAR: c00000000000da68 IRQMASK: 0 
[12689.799444] PACATMSCRATCH: 800000010280b033 
[12689.799444] GPR00: 0000000000000000 c000000050ff7590 c000000001ba8100 c0000003ccf6dd00 
[12689.799444] GPR04: c00000031027dd00 0000000000010000 0000000000000000 0000000000002300 
[12689.799444] GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 
[12689.799444] GPR12: 0000000000000000 c0000000030d0000 0000000000000000 0000000000000000 
[12689.799444] GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 
[12689.799444] GPR20: 0000000000000000 0000000000000000 0000000000000000 c000000045beab00 
[12689.799444] GPR24: 0000000000000000 0000000000000001 c00c000000f33d80 0000000010010000 
[12689.799444] GPR28: c00000004575fe00 c000000050ff7b38 0000000010000000 c00c000000c409c0 
[12689.799507] NIP [c00000000000dbac] interrupt_return_srr_kernel+0x15c/0x18c
[12689.799518] LR [c0000000008657f0] dump_user_range+0x100/0x570
[12689.799525] Call Trace:
[12689.799529] [c000000050ff7690] [c0000000008657f0] dump_user_range+0x100/0x570
[12689.799536] [c000000050ff7770] [c00000000085aefc] elf_core_dump+0x52c/0x5c0
[12689.799545] [c000000050ff7980] [c000000000864a20] coredump_write+0xe0/0x410
[12689.799552] [c000000050ff7a10] [c000000000864e10] do_coredump.constprop.0+0xc0/0x4e0
[12689.799559] [c000000050ff7af0] [c00000000086558c] vfs_coredump+0x35c/0x4c0
[12689.799565] [c000000050ff7c30] [c000000000256808] get_signal+0x918/0xad0
[12689.799573] [c000000050ff7d20] [c000000000021ba8] do_signal+0x78/0x330
[12689.799582] [c000000050ff7dc0] [c0000000014f6d48] irqentry_exit+0x358/0x990
[12689.799589] [c000000050ff7e20] [c00000000002f554] program_check_exception+0xd4/0x100
[12689.799596] [c000000050ff7e50] [c000000000009b2c] program_check_common_virt+0x3bc/0x3c0
[12689.799604] ---- interrupt: 700 at 0x10001e8c
[12689.799610] NIP:  0000000010001e8c LR: 0000000010001e74 CTR: 00007fffba290590
[12689.799615] REGS: c000000050ff7e80 TRAP: 0700   Tainted: G            E        (7.3.0-rc2-next-20260907)
[12689.799620] MSR:  8000000302a0f033 <SF,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE,TM[SE]>  CR: 240044a0  XER: 00000000
[12689.799640] CFAR: 00007fffba2905bc IRQMASK: 0 
[12689.799640] PACATMSCRATCH: 800000010280b033 
[12689.799640] GPR00: 0000000010001e74 00007fffa2fdd3c0 0000000010027f00 0000000022bde198 
[12689.799640] GPR04: 00007fffa2fdd384 00007fffba48004c 00007fffba480090 00007fffba480048 
[12689.799640] GPR08: 00000001457bc331 0000000022bde198 0000000000000000 0000000022bde198 
[12689.799640] GPR12: 00007fffba290590 00007fffa2fe68e0 0000000000000000 00007fffa2fdf1e0 
[12689.799640] GPR16: 0000000000000000 00007fffa2fdf8e0 0000000000000720 0000000000000000 
[12689.799640] GPR20: 0000000000000000 00007fffba580000 000000000080e9e0 00007fffa27d0000 
[12689.799640] GPR24: 0000000000000001 00007ffff129f3a0 0000000000000000 00007fffa2fde8f8 
[12689.799640] GPR28: 000000000000000a 0000000000000000 00000000100201bc 000000000011af5c 
[12689.799703] NIP [0000000010001e8c] 0x10001e8c
[12689.799707] LR [0000000010001e74] 0x10001e74
[12689.799711] ---- interrupt: 700
[12689.799714] Code: 7c8903a6 7ca103a6 f8010020 e8410040 e8610048 e8810050 e8a10058 40c6001c 7ccff120 e8c10060 e8010030 e8210038 <4c000024> 48000000 7ccff120 f92d0080 
[12689.799736] ---[ end trace 0000000000000000 ]---

Regards,
Venkat.
> Regards,
> 
> Venkat.
> 
>> 
>> Below are the details of the crash as reported by CI.
>> 
>> Crash Details:
>> 
>> [ 9798.880148] Unexpected TM Bad Thing exception at c00000000000dbac
>>               (msr 0x8000000302a03031) tm_scratch=800000010280b033
>> [ 9798.880160] Oops: Unrecoverable exception, sig: 6 [#1]
>> [ 9798.880165] LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=8192 NUMA pSeries
>> [ 9798.880173] Modules linked in: nvram(E) rpadlpar_io(E) rpaphp(E) ...
>> [ 9798.880233] CPU: 8 UID: 0 PID: 1039530 Comm: sigfuz
>>               Tainted: G            E       7.1.0-rc1 #1 PREEMPT
>> [ 9798.880245] Hardware name: IBM,8375-42A POWER9 (architected)
>>               hv:phyp pSeries
>> [ 9798.880251] NIP:  c00000000000dbac LR: 0000000010001e58
>> [ 9798.880262] MSR:  8000000302a03031 <SF,VEC,VSX,FP,ME,IR,DR,LE,TM[SE]>
>> 
>> 
>> Call Trace:
>> 
>> 
>> NIP [c00000000000dbac] interrupt_return_srr_kernel+0x15c/0x18c
>> Call Trace:
>> tm_reclaim_thread
>> flush_tmregs_to_thread
>> vsr_get
>> regset_get_alloc
>> fill_thread_core_info.isra.0
>> fill_note_info
>> elf_core_dump
>> coredump_write
>> do_coredump
>> vfs_coredump
>> get_signal
>> do_signal
>> do_notify_resume
>> interrupt_exit_user_prepare_main
>> interrupt_exit_user_prepare
>> interrupt_return_srr_user
>> 
>> 
>> Please let me know if further details are required.
>> 
>> 
>> If you happen to fix this issue, please add below tag.
>> 
>> Reported-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
>> 
>> 
>> 
>> Regards,
>> 
>> Venkat.
>> 
>>