From: Venkat Rao Bagalkote <venkat88@linux•ibm.com>
To: Peter Zijlstra <peterz@infradead•org>,
Shrikanth Hegde <sshegde@linux•ibm.com>,
Srikar Dronamraju <srikar@linux•ibm.com>,
Madhavan Srinivasan <maddy@linux•ibm.com>
Cc: linuxppc-dev <linuxppc-dev@lists•ozlabs.org>,
LKML <linux-kernel@vger•kernel.org>
Subject: [linux-next20260529] kernel BUG at kernel/sched/core.c:7512!
Date: Mon, 1 Jun 2026 12:11:35 +0530 [thread overview]
Message-ID: <7904105b-9dfa-4efd-a5ef-bc0276ed255d@linux.ibm.com> (raw)
Greetings!!!
I hit a kernel BUG on a linux-next kernel running on ppc64le (Power11
LPAR). The issue was observed once in CI (Avocado tests) and I haven’t
been able to reproduce it reliably yet.
Architecture: ppc64le (Power11, pSeries)
Kernel: 7.1.0-rc5-next-20260529
Config: PREEMPT(lazy)
CPUs: large system (NR_CPUS=8192)
So far, I have not reproduced the crash, but I am trying to stress
similar conditions using:
parallel read workloads (fio / dd)
memory pressure
Traces:
(5/8)
/home/upstreamci/avocado-fvt-wrapper/tests/avocado-misc-tests/cpu/ppc64_cpu_test.py:PPC64Test.test_smt_loop;run-run_type-upstream-9cfe:
STARTED
[ 1885.176400] crash hp: kexec_trylock() failed, kdump image may be
inaccurate
[ 1885.296164] crash hp: kexec_trylock() failed, kdump image may be
inaccurate
[ 1885.386120] crash hp: kexec_trylock() failed, kdump image may be
inaccurate
[ 1885.556134] crash hp: kexec_trylock() failed, kdump image may be
inaccurate
[ 1886.576119] crash hp: kexec_trylock() failed, kdump image may be
inaccurate
[ 1886.806060] crash hp: kexec_trylock() failed, kdump image may be
inaccurate
[ 1887.026051] crash hp: kexec_trylock() failed, kdump image may be
inaccurate
[ 1887.456075] ------------[ cut here ]------------
[ 1887.456101] kernel BUG at kernel/sched/core.c:7512!
[ 1887.456107] Oops: Exception in kernel mode, sig: 5 [#1]
[ 1887.456111] LE PAGE_SIZE=4K MMU=Radix SMP NR_CPUS=8192 NUMA pSeries
[ 1887.456116] Modules linked in: 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 ip_set rfkill nf_tables fsdev_dax kmem device_dax pseries_rng
vmx_crypto dax_pmem fuse ext4 crc16 mbcache jbd2 sd_mod nd_pmem papr_scm
sg libnvdimm ibmvscsi ibmveth scsi_transport_srp pseries_wdt
[ 1887.456173] CPU: 28 UID: 0 PID: 85305 Comm: kexec Not tainted
7.1.0-rc5-next-20260529 #1 PREEMPT(lazy)
[ 1887.456180] Hardware name: IBM,9080-HEX Power11 (architected)
0x820200 0xf000007 of:IBM,FW1110.01 (NH1110_069) hv:phyp pSeries
[ 1887.456185] NIP: c0000000013a8e8c LR: c0000000003483bc CTR:
0000000000000000
[ 1887.456190] REGS: c000000069f03070 TRAP: 0700 Not tainted
(7.1.0-rc5-next-20260529)
[ 1887.456195] MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR:
24428222 XER: 0000005a
[ 1887.456208] CFAR: c0000000003483b8 IRQMASK: 0
[ 1887.456208] GPR00: c0000000003483bc c000000069f03330 c000000001a82100
c000000069f033e0
[ 1887.456208] GPR04: 0000000000000000 0000000000000001 0000000000000001
c000000006dd3b00
[ 1887.456208] GPR08: ffffffffffffff00 0000000000000001 0000000000000000
0000000024428220
[ 1887.456208] GPR12: 0000000000000300 c000000effdbef00 0000000000000000
0000000000000000
[ 1887.456208] GPR16: 0000000000000000 0000000000000000 0000000000000000
0000000000000000
[ 1887.456208] GPR20: 0000000000000000 0000000000000000 0000000000000000
0000000000000000
[ 1887.456208] GPR24: 0000000000000000 0000000000000000 0000000000000000
0000000000000000
[ 1887.456208] GPR28: 0000000000000000 0000000000000000 0000000000000000
c000000069f033e0
[ 1887.456265] NIP [c0000000013a8e8c] preempt_schedule_irq+0x44/0x118
[ 1887.456274] LR [c0000000003483bc]
dynamic_irqentry_exit_cond_resched+0x40/0x1a4
[ 1887.456282] Call Trace:
[ 1887.456284] [c000000069f03360] [c0000000003483bc]
dynamic_irqentry_exit_cond_resched+0x40/0x1a4
[ 1887.456291] [c000000069f03380] [c00000000014f3bc]
do_page_fault+0xc0/0x104
[ 1887.456298] [c000000069f033b0] [c000000000008be0]
data_access_common_virt+0x210/0x220
[ 1887.456306] ---- interrupt: 300 at __copy_tofrom_user_base+0xac/0x5a4
[ 1887.456313] NIP: c00000000017fc38 LR: c000000000aaa684 CTR:
0000000000000000
[ 1887.456317] REGS: c000000069f033e0 TRAP: 0300 Not tainted
(7.1.0-rc5-next-20260529)
[ 1887.456322] MSR: 8000000002009033 <SF,VEC,EE,ME,IR,DR,RI,LE> CR:
24428220 XER: 2004005a
[ 1887.456334] CFAR: c00000000017fc34 DAR: 00003fff879a8000 DSISR:
42000000 IRQMASK: 0
[ 1887.456334] GPR00: 0000000000000000 c000000069f036a0 c000000001a82100
00003fff879a8000
[ 1887.456334] GPR04: c0000000bb314ff0 0000000000001000 69f0000606480600
0200c4080368f028
[ 1887.456334] GPR08: 09036af00005d9c4 0600000200e80803 0000000000000000
0000000000000030
[ 1887.456334] GPR12: 0000000000000040 c000000effdbef00 0000000000000000
000000000000000e
[ 1887.456334] GPR16: 0000000004a00000 000000000000001f c000000069f038a0
c00000006e73e500
[ 1887.456334] GPR20: c00000006f0ff6a8 0000000000000000 c00000006f0ff540
0000000000000001
[ 1887.456334] GPR24: 000000001816ce60 c0000000bb314000 c000000002e48730
c000000069f03a30
[ 1887.456334] GPR28: c0000000bb314000 00003fff879a7010 0000000000000010
0000000000001000
[ 1887.456393] NIP [c00000000017fc38] __copy_tofrom_user_base+0xac/0x5a4
[ 1887.456399] LR [c000000000aaa684] raw_copy_to_user+0x12c/0x314
[ 1887.456405] ---- interrupt: 300
[ 1887.456408] [c000000069f036a0] [c000000000aaa5f4]
raw_copy_to_user+0x9c/0x314 (unreliable)
[ 1887.456416] [c000000069f036e0] [c000000000aacd08]
_copy_to_iter+0xe4/0x79c
[ 1887.456423] [c000000069f037a0] [c000000000ab01ec]
copy_page_to_iter+0xd4/0x1a4
[ 1887.456429] [c000000069f037f0] [c0000000005ddc34]
filemap_read+0x420/0x4f0
[ 1887.456436] [c000000069f039c0] [c0080000043443e0]
ext4_file_read_iter+0x78/0x31c [ext4]
[ 1887.456517] [c000000069f03a10] [c000000000796498] vfs_read+0x2a8/0x3c8
[ 1887.456524] [c000000069f03ac0] [c00000000079726c] ksys_read+0x88/0x140
[ 1887.456530] [c000000069f03b10] [c000000000032f98]
system_call_exception+0x198/0x4e0
[ 1887.456537] [c000000069f03e30] [c00000000000d05c]
system_call_vectored_common+0x15c/0x2ec
[ 1887.456544] ---- interrupt: 3000 at 0x3fff9b133cf4
[ 1887.456549] NIP: 00003fff9b133cf4 LR: 00003fff9b133cf4 CTR:
0000000000000000
[ 1887.456554] REGS: c000000069f03e60 TRAP: 3000 Not tainted
(7.1.0-rc5-next-20260529)
[ 1887.456558] MSR: 800000000000f033 <SF,EE,PR,FP,ME,IR,DR,RI,LE> CR:
44424402 XER: 00000000
[ 1887.456572] IRQMASK: 0
[ 1887.456572] GPR00: 0000000000000003 00003fffe5fb4190 0000000105087f00
0000000000000003
[ 1887.456572] GPR04: 00003fff82e93010 000000001816ce60 0000000000000022
0000000000000000
[ 1887.456572] GPR08: 0000000000000000 0000000000000000 0000000000000000
0000000000000000
[ 1887.456572] GPR12: 0000000000000000 00003fff9b4cd860 000000010507f588
0000000000000000
[ 1887.456572] GPR16: ffffffffffffffff 0000000000000000 0000000000000006
0000000000000000
[ 1887.456572] GPR20: 0000000000000001 00003fff9b23039c 00003fff9b2303a0
00003fffe5fb5ee7
[ 1887.456572] GPR24: 0000000000000000 0000000000000000 00003fffe5fb5ee7
00003fffe5fb42d0
[ 1887.456572] GPR28: 0000000000000003 00003fff82e93010 000000001816ce60
0000000000000000
[ 1887.456626] NIP [00003fff9b133cf4] 0x3fff9b133cf4
[ 1887.456630] LR [00003fff9b133cf4] 0x3fff9b133cf4
[ 1887.456634] ---- interrupt: 3000
[ 1887.456637] Code: fbe1fff8 e92d0128 f8010010 f821ffd1 81490000
39200001 2c0a0000 40820014 892d0152 552907fe 7d290034 5529d97e
<0b090000> 60000000 3bc00000 ebed0128
[ 1887.456657] ---[ end trace 0000000000000000 ]---
If you happen to fix this, please add below tag.
Reported-by: Venkat Rao Bagalkote <venkat88@linux•ibm.com>
Regards,
Venkat.
next reply other threads:[~2026-06-01 6:41 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-01 6:41 Venkat Rao Bagalkote [this message]
2026-06-01 9:16 ` [linux-next20260529] kernel BUG at kernel/sched/core.c:7512! Shrikanth Hegde
2026-06-01 9:56 ` Peter Zijlstra
2026-06-02 7:56 ` Shrikanth Hegde
2026-06-02 8:18 ` Peter Zijlstra
2026-06-02 9:56 ` Shrikanth Hegde
2026-06-02 10:03 ` Peter Zijlstra
2026-06-01 13:33 ` Venkat
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=7904105b-9dfa-4efd-a5ef-bc0276ed255d@linux.ibm.com \
--to=venkat88@linux$(echo .)ibm.com \
--cc=linux-kernel@vger$(echo .)kernel.org \
--cc=linuxppc-dev@lists$(echo .)ozlabs.org \
--cc=maddy@linux$(echo .)ibm.com \
--cc=peterz@infradead$(echo .)org \
--cc=srikar@linux$(echo .)ibm.com \
--cc=sshegde@linux$(echo .)ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox