While running kselftest ftracetest on i386 the kernel crash reported on linux next tag 5.9.0-rc5-next-20200921. Good news is that this crash is not seen on today's linux next tag 20200923.

metadata: git branch: master git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git describe: next-20200921 make_kernelversion: 5.9.0-rc5 kernel-config: http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-core2-32/lkft/...

Reproduce steps: - cd /opt/kselftests/default-in-kernel/ftrace - ./ftracetest

crash log, -------------- [ 366.934246] BUG: kernel NULL pointer dereference, address: 00000024 [ 366.940528] #PF: supervisor read access in kernel mode [ 366.945683] #PF: error_code(0x0000) - not-present page [ 366.950828] *pde = 00000000 [ 366.953717] Oops: 0000 [#1] SMP [ 366.956862] CPU: 2 PID: 0 Comm: swapper/2 Tainted: G W 5.9.0-rc5-next-20200921 #1 [ 366.965639] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS 2.0b 07/27/2017 [ 366.973119] EIP: trace_event_raw_event_sched_switch+0x10/0x180 [ 366.978950] Code: 08 5b 5e 5f 5d c3 8d 74 26 00 31 c0 eb e4 e8 07 42 dd 00 8d b4 26 00 00 00 00 55 89 e5 57 56 53 89 c6 89 cf 83 ec 28 8b 45 08 <8b> 5e 24 89 55 cc 89 45 d0 65 a1 14 00 00 00 89 45 f0 31 c0 f6 c7 [ 366.997687] EAX: f5582480 EBX: f5582480 ECX: f5585b40 EDX: 00000000 [ 367.003945] ESI: 00000000 EDI: f5585b40 EBP: f5593f20 ESP: f5593eec [ 367.010203] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210092 [ 367.016978] CR0: 80050033 CR2: 00000024 CR3: 0bfbc000 CR4: 003506d0 [ 367.023236] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 367.029495] DR6: fffe0ff0 DR7: 00000400 [ 367.033323] Call Trace: [ 367.035771] ? cpu_cgroup_can_attach+0x90/0x90 [ 367.040215] ? exc_general_protection+0x280/0x280 [ 367.044922] __schedule+0x4dc/0xa90 [ 367.048415] schedule_idle+0x1c/0x40 [ 367.051993] do_idle+0x185/0x2a0 [ 367.055226] cpu_startup_entry+0x25/0x30 [ 367.059142] start_secondary+0x106/0x140 [ 367.063061] startup_32_smp+0x164/0x168 [ 367.066902] Modules linked in: sch_fq 8021q iptable_filter xt_mark ip_tables cls_bpf veth algif_hash x86_pkg_temp_thermal fuse [last unloaded: test_bpf] [ 367.080550] CR2: 0000000000000024 [ 367.083871] ---[ end trace 41a54e0211ae9de1 ]--- [ 367.083872] BUG: kernel NULL pointer dereference, address: 00000024 [ 367.083873] #PF: supervisor read access in kernel mode [ 367.088489] EIP: trace_event_raw_event_sched_switch+0x10/0x180 [ 367.094743] #PF: error_code(0x0000) - not-present page [ 367.094744] *pde = 00000000 [ 367.099877] Code: 08 5b 5e 5f 5d c3 8d 74 26 00 31 c0 eb e4 e8 07 42 dd 00 8d b4 26 00 00 00 00 55 89 e5 57 56 53 89 c6 89 cf 83 ec 28 8b 45 08 <8b> 5e 24 89 55 cc 89 45 d0 65 a1 14 00 00 00 89 45 f0 31 c0 f6 c7 [ 367.099878] EAX: f5582480 EBX: f5582480 ECX: f5585b40 EDX: 00000000 [ 367.105709] [ 367.105710] Oops: 0000 [#2] SMP [ 367.110846] ESI: 00000000 EDI: f5585b40 EBP: f5593f20 ESP: f5593eec [ 367.110847] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210092 [ 367.113725] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G D W 5.9.0-rc5-next-20200921 #1 [ 367.132462] CR0: 80050033 CR2: 00000024 CR3: 0bfbc000 CR4: 003506d0 [ 367.132463] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 367.138718] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS 2.0b 07/27/2017 [ 367.138720] EIP: trace_event_raw_event_sched_switch+0x10/0x180 [ 367.140210] DR6: fffe0ff0 DR7: 00000400 [ 367.140211] Kernel panic - not syncing: Attempted to kill the idle task! [ 367.143348] Code: 08 5b 5e 5f 5d c3 8d 74 26 00 31 c0 eb e4 e8 07 42 dd 00 8d b4 26 00 00 00 00 55 89 e5 57 56 53 89 c6 89 cf 83 ec 28 8b 45 08 <8b> 5e 24 89 55 cc 89 45 d0 65 a1 14 00 00 00 89 45 f0 31 c0 f6 c7 [ 367.220218] EAX: d5ebb6c0 EBX: d5ebb6c0 ECX: cbca0700 EDX: 00000000 [ 367.226476] ESI: 00000000 EDI: cbca0700 EBP: cbc8bef0 ESP: cbc8bebc [ 367.232733] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210092 [ 367.239512] CR0: 80050033 CR2: 00000024 CR3: 0bfbc000 CR4: 003506d0 [ 367.245767] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 367.252025] DR6: fffe0ff0 DR7: 00000400 [ 367.255855] Call Trace: [ 367.258302] ? pick_next_task_fair+0x154/0x3a0 [ 367.262748] __schedule+0x4dc/0xa90 [ 367.266240] schedule_idle+0x1c/0x40 [ 367.269819] do_idle+0x185/0x2a0 [ 367.273053] cpu_startup_entry+0x25/0x30 [ 367.276978] rest_init+0x166/0x230 [ 367.280375] arch_call_rest_init+0xd/0x19 [ 367.284380] start_kernel+0x481/0x4a0 [ 367.288045] i386_start_kernel+0x48/0x4a [ 367.291970] startup_32_smp+0x164/0x168 [ 367.295803] Modules linked in: sch_fq 8021q iptable_filter xt_mark ip_tables cls_bpf veth algif_hash x86_pkg_temp_thermal fuse [last unloaded: test_bpf] [ 367.309450] CR2: 0000000000000024 [ 367.312762] ---[ end trace 41a54e0211ae9de2 ]--- [ 367.312763] BUG: kernel NULL pointer dereference, address: 00000024 [ 367.312764] #PF: supervisor read access in kernel mode [ 367.317381] EIP: trace_event_raw_event_sched_switch+0x10/0x180 [ 367.323637] #PF: error_code(0x0000) - not-present page [ 367.323638] *pde = 00000000 [ 367.328769] Code: 08 5b 5e 5f 5d c3 8d 74 26 00 31 c0 eb e4 e8 07 42 dd 00 8d b4 26 00 00 00 00 55 89 e5 57 56 53 89 c6 89 cf 83 ec 28 8b 45 08 <8b> 5e 24 89 55 cc 89 45 d0 65 a1 14 00 00 00 89 45 f0 31 c0 f6 c7 [ 367.328770] EAX: f5582480 EBX: f5582480 ECX: f5585b40 EDX: 00000000 [ 367.334600] [ 367.334601] Oops: 0000 [#3] SMP [ 367.339731] ESI: 00000000 EDI: f5585b40 EBP: f5593f20 ESP: f5593eec [ 367.339732] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210092 [ 367.342611] CPU: 1 PID: 0 Comm: swapper/1 Tainted: G D W 5.9.0-rc5-next-20200921 #1 [ 367.361346] CR0: 80050033 CR2: 00000024 CR3: 0bfbc000 CR4: 003506d0 [ 367.361347] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 367.367602] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS 2.0b 07/27/2017 [ 367.367604] EIP: trace_event_raw_event_sched_switch+0x10/0x180 [ 367.369095] DR6: fffe0ff0 DR7: 00000400 [ 367.423685] Code: 08 5b 5e 5f 5d c3 8d 74 26 00 31 c0 eb e4 e8 07 42 dd 00 8d b4 26 00 00 00 00 55 89 e5 57 56 53 89 c6 89 cf 83 ec 28 8b 45 08 <8b> 5e 24 89 55 cc 89 45 d0 65 a1 14 00 00 00 89 45 f0 31 c0 f6 c7 [ 367.442431] EAX: f2dca480 EBX: f2dca480 ECX: f5584900 EDX: 00000000 [ 367.448687] ESI: 00000000 EDI: f5584900 EBP: f5591f20 ESP: f5591eec [ 367.454945] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210092 [ 367.461722] CR0: 80050033 CR2: 00000024 CR3: 0bfbc000 CR4: 003506d0 [ 367.467980] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 367.474236] DR6: fffe0ff0 DR7: 00000400 [ 367.478067] Call Trace: [ 367.480514] ? pick_next_task_fair+0x154/0x3a0 [ 367.484961] __schedule+0x4dc/0xa90 [ 367.488453] ? inet_rtm_getroute+0x214/0x990 [ 367.492724] schedule_idle+0x1c/0x40 [ 367.496302] do_idle+0x185/0x2a0 [ 367.499526] ? inet_rtm_getroute+0x214/0x990 [ 367.503792] cpu_startup_entry+0x25/0x30 [ 367.507715] start_secondary+0x106/0x140 [ 367.511633] ? inet_rtm_getroute+0x214/0x990 [ 367.515898] startup_32_smp+0x164/0x168 [ 367.519738] Modules linked in: sch_fq 8021q iptable_filter xt_mark ip_tables cls_bpf veth algif_hash x86_pkg_temp_thermal fuse [last unloaded: test_bpf] [ 367.533385] CR2: 0000000000000024 [ 367.536698] ---[ end trace 41a54e0211ae9de3 ]--- [ 367.541316] EIP: trace_event_raw_event_sched_switch+0x10/0x180 [ 367.547140] Code: 08 5b 5e 5f 5d c3 8d 74 26 00 31 c0 eb e4 e8 07 42 dd 00 8d b4 26 00 00 00 00 55 89 e5 57 56 53 89 c6 89 cf 83 ec 28 8b 45 08 <8b> 5e 24 89 55 cc 89 45 d0 65 a1 14 00 00 00 89 45 f0 31 c0 f6 c7 [ 367.565877] EAX: f5582480 EBX: f5582480 ECX: f5585b40 EDX: 00000000 [ 367.572135] ESI: 00000000 EDI: f5585b40 EBP: f5593f20 ESP: f5593eec [ 367.578391] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210092 [ 367.585170] CR0: 80050033 CR2: 00000024 CR3: 0bfbc000 CR4: 003506d0 [ 367.591433] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 [ 367.597691] DR6: fffe0ff0 DR7: 00000400 [ 368.219291] Shutting down cpus with NMI [ 368.223134] Kernel Offset: disabled [ 368.226617] ---[ end Kernel panic - not syncing: Attempted to kill the idle task! ]---

full test log, https://lkft.validation.linaro.org/scheduler/job/1784011 https://lkft.validation.linaro.org/scheduler/job/1776849#L9308