While running LTP tracing ftrace-stress-test kernel on x86_64 got panic on stable rc 4.19 branch. I have checked this kernel panic has been happening from the beginning of 4.19 release. I will run git bisect starting from 4.18 and get back to you on this email thread.

steps to reproduce: # Boot qemu x86_64 with trace configs enabled. # cd /opt/ltp # ./runltp -f tracing

Test output log: --------------------- ftrace-stress-test 1 TINFO: Start pid16=3123 /opt/ltp/testcases/bin/ftrace_stress/ftrace_tracing_cpumask.sh ftrace-stress-test 1 TINFO: Start pid17=3124 /opt/ltp/testcases/bin/ftrace_stress/ftrace_set_ftrace_filter.sh [ 81.695606] Core dump to |/bin/false pipe failed [ 81.696936] false (3169) used greatest stack depth: 11224 bytes left [ 81.711194] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b [ 81.711194] [ 81.720342] CPU: 2 PID: 1 Comm: systemd Not tainted 4.19.142-rc2 #1 [ 81.726622] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS 2.0b 07/27/2017 [ 81.734121] Call Trace: [ 81.736599] ? ftrace_graph_caller+0xb0/0xb0 [ 81.740890] dump_stack+0x7a/0xaa [ 81.744245] panic+0xe6/0x239 [ 81.747260] ? panic+0x5/0x239 [ 81.750343] ? ftrace_graph_caller+0xb0/0xb0 [ 81.754633] do_exit.cold+0xa0/0xb7 [ 81.758138] ? do_exit+0x5/0xb40 [ 81.761389] ? ftrace_return_to_handler+0x99/0xf0 [ 81.766115] ? ftrace_graph_caller+0xb0/0xb0 [ 81.770399] do_group_exit+0x47/0xb0 [ 81.773992] ? ftrace_graph_caller+0xb0/0xb0 [ 81.778277] get_signal+0x158/0x7e0 [ 81.781797] do_signal+0x37/0x640 [ 81.785136] ? trace_event_raw_event_rcu_dyntick+0x75/0xc0 [ 81.790658] exit_to_usermode_loop+0x78/0xd0 [ 81.794946] prepare_exit_to_usermode+0x66/0x90 [ 81.799495] ? page_fault+0x8/0x30 [ 81.802915] retint_user+0x8/0x18 [ 81.806259] RIP: 0033:0x7f62d3b648a8 [ 81.809850] Code: fe ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 66 0f ef c0 48 89 e5 41 56 41 54 53 48 81 ec 98 08 00 00 48 8b 45 28 <0f> 29 85 90 f7 ff ff 8b 1d 0f 68 38 00 0f 29 85 a0 f7 ff ff 4c 8b [ 81.828611] RSP: 002b:00007ffe44822e80 EFLAGS: 00010202 [ 81.833854] RAX: 00007ffe44823950 RBX: 00007ffe44823950 RCX: 00000000000000d7 [ 81.840997] RDX: 000055a3d336bc15 RSI: 0000000000000000 RDI: 0000000000000018 [ 81.848138] RBP: 00007ffe44823730 R08: 000055a3d336e9c5 R09: 0000000000000000 [ 81.855278] R10: 00007ffe44823788 R11: 0000000000000000 R12: 00007ffe44823800 [ 81.862419] R13: 00000000000000d7 R14: 00007ffe44823840 R15: 0000000000000018 [ 81.869625] Kernel Offset: 0x1f800000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [ 81.880417] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b [ 81.880417] ]--- [ 81.890803] ------------[ cut here ]------------ [ 81.895440] sched: Unexpected reschedule of offline CPU#3! [ 81.900946] WARNING: CPU: 2 PID: 1 at arch/x86/kernel/smp.c:128 native_smp_send_reschedule+0x3a/0x40 [ 81.910087] Modules linked in: x86_pkg_temp_thermal [ 81.914984] CPU: 2 PID: 1 Comm: systemd Not tainted 4.19.142-rc2 #1 [ 81.921266] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS 2.0b 07/27/2017 [ 81.928762] RIP: 0010:native_smp_send_reschedule+0x3a/0x40 [ 81.934257] Code: b7 8f 01 73 17 48 8b 05 c4 2d 58 01 be fd 00 00 00 48 8b 40 30 e8 b6 ea f4 00 5d c3 89 fe 48 c7 c7 b8 9a d3 a1 e8 c2 e1 0b 00 <0f> 0b 5d c3 66 90 e8 ab a3 d4 00 55 48 89 e5 53 48 83 ec 10 65 48 [ 81.953021] RSP: 0000:ffff9ad0dfb03d38 EFLAGS: 00010082 [ 81.958265] RAX: 0000000000000000 RBX: ffff9ad0dfb9fb40 RCX: 000000000000001f [ 81.965404] RDX: 0000000000000007 RSI: ffff9ad0da7c6000 RDI: ffffffffa08b755a [ 81.972545] RBP: ffff9ad0dfb03d38 R08: 0000000000000000 R09: ffffb7044002ff58 [ 81.979686] R10: 0000000000000000 R11: ffff9ad0dda48000 R12: 0000000000000003 [ 81.986830] R13: ffff9ad0dfb9fb40 R14: ffff9ad0dfb03df8 R15: ffff9ad0dfb03df8 [ 81.993979] FS: 00007f62d4103840(0000) GS:ffff9ad0dfb00000(0000) knlGS:0000000000000000 [ 82.002082] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 82.007846] CR2: 0000000000000000 CR3: 000000045c4e2003 CR4: 00000000003606e0 [ 82.014995] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 82.022146] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 82.029294] Call Trace: [ 82.031767] <IRQ> [ 82.033804] ? ftrace_graph_caller+0xb0/0xb0 [ 82.038093] resched_curr+0x5e/0xc0 [ 82.041606] ? ftrace_graph_caller+0xb0/0xb0 [ 82.045891] check_preempt_curr+0x4e/0x90 [ 82.049923] ? ftrace_graph_caller+0xb0/0xb0 [ 82.054213] ttwu_do_wakeup+0x1e/0x140 [ 82.057978] ? ftrace_graph_caller+0xb0/0xb0 [ 82.062262] ttwu_do_activate+0x6c/0x90 [ 82.066125] ? ftrace_graph_caller+0xb0/0xb0 [ 82.070409] try_to_wake_up+0x205/0x4b0 [ 82.074259] ? try_to_wake_up+0x5/0x4b0 [ 82.078115] ? default_wake_function+0x5/0x20 [ 82.082498] ? ftrace_graph_caller+0xb0/0xb0 [ 82.086788] default_wake_function+0x12/0x20 [ 82.091071] ? ftrace_graph_caller+0xb0/0xb0 [ 82.095361] autoremove_wake_function+0x12/0x40 [ 82.099915] ? ftrace_graph_caller+0xb0/0xb0 [ 82.104200] __wake_up_common+0x7e/0x140 [ 82.108152] ? ftrace_graph_caller+0xb0/0xb0 [ 82.112441] __wake_up_common_lock+0x7b/0xf0 [ 82.116733] ? ftrace_graph_caller+0xb0/0xb0 [ 82.121024] __wake_up+0x13/0x20 [ 82.124276] ? ftrace_graph_caller+0xb0/0xb0 [ 82.128564] wake_up_klogd_work_func+0x5c/0x60 [ 82.133028] ? ftrace_graph_caller+0xb0/0xb0 [ 82.137317] irq_work_run_list+0x4f/0x70 [ 82.141261] ? set_memory_decrypted+0x10/0x10 [ 82.145636] irq_work_run+0x2c/0x40 [ 82.149139] flush_smp_call_function_queue+0x72/0xf0 [ 82.154123] ? ftrace_graph_caller+0xb0/0xb0 [ 82.158412] generic_smp_call_function_single_interrupt+0x13/0x2b [ 82.164522] ? ftrace_graph_caller+0xb0/0xb0 [ 82.168810] smp_call_function_interrupt+0x3e/0xd0 [ 82.173623] ? ftrace_graph_caller+0xb0/0xb0 [ 82.177910] call_function_interrupt+0xf/0x20 [ 82.182287] </IRQ> [ 82.184411] RIP: 0010:panic+0x1fa/0x239 [ 82.188266] Code: b0 83 3d e3 5f a3 01 00 74 05 e8 4c 6c 02 00 48 c7 c6 a0 b9 3a a2 48 c7 c7 d0 2c d4 a1 e8 9c fb 05 00 e8 74 58 0e 00 fb 31 db <4c> 39 eb 7c 1d 41 83 f4 01 48 8b 05 91 5f a3 01 44 89 e7 e8 49 06 [ 82.207019] RSP: 0000:ffffb7044002fc40 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff03 [ 82.214603] RAX: ffffb7044002fcb0 RBX: 0000000000000000 RCX: 000000000000001f [ 82.221754] RDX: 0000000000000001 RSI: ffffffffa16019c0 RDI: ffffffffa097599c [ 82.228902] RBP: ffffb7044002fcb0 R08: 0000000000000000 R09: ffffb7044002ff58 [ 82.236044] R10: 0000000000000000 R11: ffff9ad0dda48000 R12: 0000000000000000 [ 82.243194] R13: 0000000000000000 R14: ffffb7044002fe01 R15: 000000000000000b [ 82.250354] ? ftrace_graph_caller+0xb0/0xb0 [ 82.254644] ? panic+0x1f7/0x239 [ 82.257901] ? panic+0x5/0x239 [ 82.260979] ? ftrace_graph_caller+0xb0/0xb0 [ 82.265271] do_exit.cold+0xa0/0xb7 [ 82.268781] ? do_exit+0x5/0xb40 [ 82.272030] ? ftrace_return_to_handler+0x99/0xf0 [ 82.276759] ? ftrace_graph_caller+0xb0/0xb0 [ 82.281044] do_group_exit+0x47/0xb0 [ 82.284642] ? ftrace_graph_caller+0xb0/0xb0 [ 82.288930] get_signal+0x158/0x7e0 [ 82.292449] do_signal+0x37/0x640 [ 82.295787] ? trace_event_raw_event_rcu_dyntick+0x75/0xc0 [ 82.301309] exit_to_usermode_loop+0x78/0xd0 [ 82.305598] prepare_exit_to_usermode+0x66/0x90 [ 82.310145] ? page_fault+0x8/0x30 [ 82.313570] retint_user+0x8/0x18 [ 82.316904] RIP: 0033:0x7f62d3b648a8 [ 82.320493] Code: fe ff ff 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 66 0f ef c0 48 89 e5 41 56 41 54 53 48 81 ec 98 08 00 00 48 8b 45 28 <0f> 29 85 90 f7 ff ff 8b 1d 0f 68 38 00 0f 29 85 a0 f7 ff ff 4c 8b [ 82.339254] RSP: 002b:00007ffe44822e80 EFLAGS: 00010202 [ 82.344498] RAX: 00007ffe44823950 RBX: 00007ffe44823950 RCX: 00000000000000d7 [ 82.351647] RDX: 000055a3d336bc15 RSI: 0000000000000000 RDI: 0000000000000018 [ 82.358789] RBP: 00007ffe44823730 R08: 000055a3d336e9c5 R09: 0000000000000000 [ 82.365931] R10: 00007ffe44823788 R11: 0000000000000000 R12: 00007ffe44823800 [ 82.373081] R13: 00000000000000d7 R14: 00007ffe44823840 R15: 0000000000000018 [ 82.380236] ---[ end trace d471dcce52203e4f ]---

full test log link, https://lkft.validation.linaro.org/scheduler/job/1705337#L1514