Comment 0 for bug 1991234

While closing bug 1906389, I found this issue with Jammy 5.15.0-48-generic on P9 node baltar

We're not running this test on PowerPC, maybe we should consider to cover this.

The ubuntu_lttng_smoke_test will hang with:
 Running '/home/ubuntu/autotest/client/tests/ubuntu_lttng_smoke_test/ubuntu_lttng_smoke_test.sh'
 == lttng smoke test of session create/destroy ==
 Session test-kernel-session created.
 Traces will be output to /tmp/lttng-kernel-trace-12196-session
 PASSED (lttng create)
 Session test-kernel-session destroyed
 PASSED (lttng destroy)

 == lttng smoke test trace context switches ==
 Session test-kernel-session created.
 Traces will be output to /tmp/lttng-kernel-trace-12196-session
 PASSED (lttng create)
(Test hang here)

In dmesg you will see:
[ 6804.283169] lttng_kretprobes: loading out-of-tree module taints kernel.
[ 6804.283265] lttng_kretprobes: module verification failed: signature and/or required key missing - tainting kernel
[ 6804.434672] BUG: Unable to handle kernel data access on read at 0xc0080000129f0000
[ 6804.434704] Faulting instruction address: 0xc0000000002a998c
[ 6804.434728] Oops: Kernel access of bad area, sig: 11 [#1]
[ 6804.434740] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV
[ 6804.434774] Modules linked in: lttng_tracer(OE+) lttng_statedump(OE) lttng_wrapper(OE) lttng_uprobes(OE) lttng_clock(OE) lttng_kprobes(OE) lttng_lib_ring_buffer(OE) lttng_kretprobes(OE) tls joydev input_leds mac_hid ofpart cmdlinepart powernv_flash at24 mtd opal_prd uio_pdrv_genirq ibmpowernv uio ipmi_powernv vmx_crypto sch_fq_codel dm_multipath pstore_blk scsi_dh_rdac scsi_dh_emc ipmi_devintf pstore_zone ramoops ipmi_msghandler scsi_dh_alua reed_solomon ip_tables x_tables autofs4 btrfs blake2b_generic zstd_compress raid10 raid456 async_raid6_recov async_memcpy async_pq async_xor async_tx xor raid6_pq libcrc32c raid1 raid0 multipath linear hid_generic ses enclosure scsi_transport_sas usbhid hid ast i2c_algo_bit drm_vram_helper drm_ttm_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops cec rc_core crct10dif_vpmsum crc32c_vpmsum drm xhci_pci i40e aacraid xhci_pci_renesas drm_panel_orientation_quirks
[ 6804.435085] CPU: 74 PID: 4534 Comm: Client manageme Tainted: G OE 5.15.0-48-generic #54-Ubuntu
[ 6804.435124] NIP: c0000000002a998c LR: c0000000002a9fd0 CTR: c0000000002a9e2c
[ 6804.435158] REGS: c0000000093cb670 TRAP: 0300 Tainted: G OE (5.15.0-48-generic)
[ 6804.435193] MSR: 900000000280b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 84228284 XER: 20040151
[ 6804.435245] CFAR: c0000000002a9fcc DAR: c0080000129f0000 DSISR: 40000000 IRQMASK: 0
               GPR00: c0000000002a9fd0 c0000000093cb910 c008000013f58100 00000000001062b8
               GPR04: c0000000093cb938 c0080000128e9d48 0000000000000080 0000000000000000
               GPR08: ffffffffffffff99 c0080000128e8100 00000000001062b9 c008000012a77ae8
               GPR12: c008000012a77ea8 c000000ffff8f100 0000000020000000 0000000000000000
               GPR16: 0000000000000000 0000000000000000 000007f1831cbec8 000007f1831cbe48
               GPR20: 000007f1831cbf28 00007e1e2c006d10 000007f1831c2478 00007e1e2c003190
               GPR24: 0000000000000000 0000000000000000 000000000004ac15 00000000001062b8
               GPR28: c008000013f40158 c008000013f40198 0000000000000000 000000000009e2b8
[ 6804.435518] NIP [c0000000002a998c] kallsyms_expand_symbol.constprop.0+0x1c/0xd0
[ 6804.435556] LR [c0000000002a9fd0] kallsyms_lookup_name+0x1b0/0x2b0
[ 6804.435590] Call Trace:
[ 6804.435607] [c0000000093cb910] [c0000000002f5394] unregister_kprobe+0x64/0xb0 (unreliable)
[ 6804.435645] [c0000000093cb9f0] [c008000013f302d4] wrapper_kallsyms_lookup_name+0x4c/0xf0 [lttng_wrapper]
[ 6804.435700] [c0000000093cba60] [c008000013f300b0] wrapper_get_pfnblock_flags_mask_init+0x28/0x60 [lttng_wrapper]
[ 6804.435749] [c0000000093cba80] [c008000014a5ead0] lttng_events_init+0x40/0x344 [lttng_tracer]
[ 6804.435884] [c0000000093cbb20] [c000000000012320] do_one_initcall+0x60/0x2d0
[ 6804.435920] [c0000000093cbc00] [c0000000002a5888] do_init_module+0x68/0x340
[ 6804.435955] [c0000000093cbc90] [c0000000002a84b4] __do_sys_finit_module+0xd4/0x160
[ 6804.435992] [c0000000093cbdb0] [c00000000002f764] system_call_exception+0x114/0x2c0
[ 6804.436028] [c0000000093cbe10] [c00000000000c1e8] system_call_vectored_common+0xe8/0x278
[ 6804.436069] --- interrupt: 3000 at 0x7e1e45445fc0
[ 6804.436091] NIP: 00007e1e45445fc0 LR: 0000000000000000 CTR: 0000000000000000
[ 6804.436125] REGS: c0000000093cbe80 TRAP: 3000 Tainted: G OE (5.15.0-48-generic)
[ 6804.436160] MSR: 900000000280f033 <SF,HV,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE> CR: 44228248 XER: 00000000
[ 6804.436211] IRQMASK: 0
               GPR00: 0000000000000161 00007e1e327b8c90 00007e1e45566e00 0000000000000048
               GPR04: 00007e1e45a1b530 0000000000000000 0000000000000048 0000000000000000
               GPR08: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
               GPR12: 0000000000000000 00007e1e327d5b00 0000000020000000 0000000000000000
               GPR16: 0000000000000000 0000000000000000 000007f1831cbec8 000007f1831cbe48
               GPR20: 000007f1831cbf28 00007e1e2c006d10 000007f1831c2478 00007e1e2c003190
               GPR24: 0000000000000000 00007e1e2c007410 00007e1e327b8fb0 00007e1e2c0073c0
               GPR28: 00007e1e45a1b530 0000000000000000 00007e1e2c007410 00007e1e2c003420
[ 6804.436425] NIP [00007e1e45445fc0] 0x7e1e45445fc0
[ 6804.436459] LR [0000000000000000] 0x0
[ 6804.436477] --- interrupt: 3000
[ 6804.436496] Instruction dump:
[ 6804.436515] 48349e9d 60000000 4bffff84 60000000 60420000 3c4c0281 3842ac90 7c0802a6
[ 6804.436557] 60000000 3d22fe99 39430001 38a91c48 <7d2518ae> 7ca32a14 2c090000 7c695214
[ 6804.436601] ---[ end trace c14a6519d9a9d0c6 ]---