Comment # 5 on bug 1185831 from Jiri Slaby

Quite interestingly, I can reproduce with kernel-obs-build from Staging:N:
$ qemu-kvm -kernel .build.kernel.kvm -initrd .build.initrd.kvm -hda /dev/null
-m 2G -append 'console=ttyS0' -serial stdio
> ...
> [    2.599705] BUG: unable to handle page fault for address: ffffffffc05ded30
> [    2.601018] #PF: supervisor write access in kernel mode
> [    2.601784] #PF: error_code(0x0003) - permissions violation
> [    2.602632] PGD 25a15067 P4D 25a15067 PUD 25a17067 PMD 480b067 PTE 8000000005504061
> [    2.603855] Oops: 0003 [#1] SMP PTI
> [    2.604387] CPU: 0 PID: 210 Comm: modprobe Not tainted 5.12.0-6-default #1 openSUSE Tumbleweed
> [    2.605788] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a-rebuilt.opensuse.org 04/01/2014
> [    2.607707] RIP: 0010:register_trace_event+0xcc/0x210
> ...
> [    2.626808] Call Trace:
> [    2.627388]  trace_event_raw_init+0x9/0x20
> [    2.628055]  event_init+0x2d/0x70
> [    2.628716]  trace_module_notify+0x108/0x1f0
> [    2.629637]  blocking_notifier_call_chain_robust+0x64/0xd0
> [    2.631256]  ? mutex_lock+0xe/0x30
> [    2.631895]  load_module+0x20e4/0x2910
> ...
> [    2.651413] Modules linked in: xfs(+) btrfs blake2b_generic xor raid6_pq libcrc32c reiserfs squashfs fuse dm_snapshot dm_bufio essiv authenc dm_crypt trusted dm_mod binfmt_misc loop sg

Note it dies during load of xfs module.

But I cannot repro with a kernel built outside OBS:
factory:~ # dmesg|head -1
> [    0.000000] Linux version 5.12.2-default (jslaby@kunlun) (gcc-11 (SUSE Linux) 11.1.1 20210429 [revision cd0a059bd384da58d43674496a79ecb7de610800], GNU ld (GNU Binutils; devel:gcc / openSUSE_Leap_15.1) 2.36.0.20210204-lp151.403) #8 SMP Tue May 11 08:07:05 CEST 2021
factory:~ # lsmod|grep xfs
> xfs                  1753088  0
> libcrc32c              16384  1 xfs

Investigating.