BUG: kernel NULL pointer dereference, address: 00000024 - ftrace

[Naresh Kamboju]

While running kselftest on i386 on Linux next 20201001 kernel this bug
was noticed.
BUG: kernel NULL pointer dereference, address: 00000024


steps to reproduce:
# cd  /opt/kselftests/ftrace
# ./ftracetest

metadata:
  git branch: master
  git repo: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
  git commit: d39294091fee6b89d9c4a683bb19441b25098330
  git describe: next-20201001ftracetest
  make_kernelversion: 5.9.0-rc7
  kernel-config:
http://snapshots.linaro.org/openembedded/lkft/lkft/sumo/intel-core2-32/lkft/linux-next/872/config

# selftests: ftrace: ftracetest
# === Ftrace unit tests ===
# [1] Basic trace file check [PASS]
# [2] Basic test for tracers [PASS]
# [3] Basic trace clock test [PASS]
# [4] Basic event tracing check [PASS]
# [5] Change the ringbuffer size [PASS]
# [6] Snapshot and tracing setting [PASS]
# [7] trace_pipe and trace_marker [PASS]
# [8] Test ftrace direct functions against tracers [UNRESOLVED]
# [9] Test ftrace direct functions against kprobes [UNRESOLVED]
# [10] Generic dynamic event - add/remove kprobe events [PASS]
# [11] Generic dynamic event - add/remove synthetic events [PASS]
# [12] Generic dynamic event - selective clear (compatibility) [PASS]
# [13] Generic dynamic event - generic clear event [PASS]
# [14] event tracing - enable/disable with event level files
[  207.481763] BUG: kernel NULL pointer dereference, address: 00000024
[  207.488050] #PF: supervisor read access in kernel mode
[  207.493205] #PF: error_code(0x0000) - not-present page
[  207.498355] *pde = 00000000
[  207.501258] Oops: 0000 [#1] SMP
[  207.504421] CPU: 2 PID: 0 Comm: swapper/2 Tainted: G        W
  5.9.0-rc7-next-20201001 #1
[  207.513205] Hardware name: Supermicro SYS-5019S-ML/X11SSH-F, BIOS
2.0b 07/27/2017
[  207.520680] EIP: trace_event_raw_event_sched_switch+0x10/0x180
[  207.526510] Code: 08 5b 5e 5f 5d c3 8d 74 26 00 31 c0 eb e4 e8 27
1d de 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
[  207.545253] EAX: f55aa480 EBX: f55aa480 ECX: f55adb40 EDX: 00000000
[  207.551510] ESI: 00000000 EDI: f55adb40 EBP: f55bbf20 ESP: f55bbeec
[  207.557769] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210092
[  207.564554] CR0: 80050033 CR2: 00000024 CR3: 10830000 CR4: 003506d0
[  207.570811] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[  207.577069] DR6: fffe0ff0 DR7: 00000400
[  207.580898] Call Trace:
[  207.583344]  ? pick_next_task_fair+0x165/0x3b0
[  207.587794]  __schedule+0x4dc/0xa90
[  207.591283]  schedule_idle+0x1c/0x40
[  207.594863]  do_idle+0x185/0x2a0
[  207.598097]  cpu_startup_entry+0x25/0x30
[  207.602021]  start_secondary+0x106/0x140
[  207.605946]  startup_32_smp+0x164/0x168
[  207.609778] Modules linked in: sch_fq sch_ingress veth algif_hash
x86_pkg_temp_thermal fuse [last unloaded: test_bpf]
[  207.620385] CR2: 0000000000000024
[  207.623697] ---[ end trace 6ad815a56bdaaf71 ]---
[  207.628342] EIP: trace_event_raw_event_sched_switch+0x10/0x180
[  207.634173] Code: 08 5b 5e 5f 5d c3 8d 74 26 00 31 c0 eb e4 e8 27
1d de 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
[  207.652918] EAX: f55aa480 EBX: f55aa480 ECX: f55adb40 EDX: 00000000
[  207.659175] ESI: 00000000 EDI: f55adb40 EBP: f55bbf20 ESP: f55bbeec
[  207.665433] DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068 EFLAGS: 00210092
[  207.672211] CR0: 80050033 CR2: 00000024 CR3: 10830000 CR4: 003506d0
[  207.678466] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
[  207.684740] DR6: fffe0ff0 DR7: 00000400
[  207.688597] Kernel panic - not syncing: Attempted to kill the idle task!
[  207.695329] Kernel Offset: disabled
[  207.698828] ---[ end Kernel panic - not syncing: Attempted to kill
the idle task! ]---


full test log,
https://lkft.validation.linaro.org/scheduler/job/1809544#L6012

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Linaro LKFT
https://lkft.linaro.org