While running LTP tracing ftrace-stress-test kernel on arm64 dragonboard bd410c got panic on stable rc 4.14 branch. I will run git bisect starting from 4.14 and get back to you on this email thread.

metadata: git branch: linux-4.14.y git repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git kernel-config: https://builds.tuxbuild.com/ia1EnWmxGbTrk8uPt4w3tA/kernel.config

steps to reproduce: # Boot arm64 db410c with trace configs enabled. # cd /opt/ltp # ./runltp -f tracing

ftrace_buffer_size_kb.sh: line 33: echo: write error: Cannot allocate memory ftrace_buffer_size_kb.sh: line 33: echo: write error: Cannot allocate memory [ 55.868262] Unable to handle kernel paging request at virtual address 800036ac1000 [ 55.868317] Mem abort info: [ 55.874729] Exception class = DABT (current EL), IL = 32 bits [ 55.877427] SET = 0, FnV = 0 [ 55.883323] EA = 0, S1PTW = 0 [ 55.886445] Data abort info: [ 55.889487] ISV = 0, ISS = 0x00000004 [ 55.892613] CM = 0, WnR = 0 [ 55.896173] user pgtable: 4k pages, 48-bit VAs, pgd = ffff8000248f1000 [ 55.899307] [0000800036ac1000] *pgd=0000000000000000 [ 55.905730] Internal error: Oops: 96000004 [#2] PREEMPT SMP [ 55.910849] Modules linked in: rfkill snd_soc_hdmi_codec crc32_ce adv7511 msm mdt_loader drm_kms_helper snd_soc_lpass_apq8016 snd_soc_msm8916_analog snd_soc_lpass_cpu snd_soc_apq8016_sbc snd_soc_msm8916_digital snd_soc_lpass_platform msm_rng rng_core drm fuse [ 55.916860] Process sh (pid: 3279, stack limit = 0xffff00000f648000) [ 55.939065] CPU: 2 PID: 3279 Comm: sh Tainted: G D 4.14.195-rc2 #1 [ 55.945662] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) [ 55.952690] task: ffff80003b6e5400 task.stack: ffff00000f648000 [ 55.959636] pc : get_trace_buf+0x14/0x40 [ 55.965274] lr : __trace_array_vprintk+0x84/0x298 [ 55.969436] sp : ffff000008013cc0 pstate : 000001c5 [ 55.974039] x29: ffff000008013cc0 x28: 0000000000000104 [ 55.978726] x27: ffff00000960bb40 x26: ffff0000093c7000 [ 55.984282] x25: 0000000000000105 x24: ffff000008081c74 [ 55.989577] x23: ffff0000081be314 x22: ffff0000093f3000 [ 55.994873] x21: ffff80003b6e5400 x20: ffff80000eb05200 [ 56.000167] x19: 0000000000000000 x18: 0000ffffa14fca70 [ 56.005462] x17: 0000ffffa146ec18 x16: ffff00000829a3d8 [ 56.010758] x15: 0000000000000040 x14: ffff0000081ccb34 [ 56.016053] x13: ffff0000081cc8d4 x12: ffff0000081cc6d0 [ 56.021348] x11: ffff0000081a8b88 x10: ffff0000081a8ae4 [ 56.026643] x9 : ffff0000081fc3bc x8 : ffff0000093f3000 [ 56.031938] x7 : ffff800009f33404 x6 : ffff0000090810d0 [ 56.037234] x5 : ffff000008013d50 x4 : 0000800036ac1000 [ 56.042528] x3 : ffff000008013d50 x2 : 0000800036ac1000 [ 56.047823] x1 : 0000000000000000 x0 : ffff000009609000 [ 56.053119] Call trace: [ 56.058410] get_trace_buf+0x14/0x40 [ 56.060583] trace_array_printk_buf+0x60/0x68 [ 56.064404] update_max_tr_single.part.0+0xfc/0x128 [ 56.068657] update_max_tr_single+0x14/0x20 [ 56.073346] check_critical_timing+0x188/0x198 [ 56.077512] stop_critical_timings.part.0+0xf0/0x110 [ 56.082026] trace_hardirqs_on+0x34/0x40 [ 56.087145] __do_softirq+0xf4/0x3f4 [ 56.091051] irq_exit+0xdc/0x120 [ 56.094612] __handle_domain_irq+0x70/0xc0 [ 56.097822] gic_handle_irq+0x58/0xb0 [ 56.101728] el1_irq+0xb4/0x12c [ 56.105458] rb_commit+0x38/0x270 [ 56.108412] ftrace_trace_userstack+0x150/0x200 [ 56.111886] trace_buffer_unlock_commit_regs+0xcc/0x150 [ 56.116229] trace_event_buffer_commit+0x6c/0x238 [ 56.121436] trace_event_raw_event_ipi_raise+0x64/0x98 [ 56.126299] smp_cross_call+0xc0/0xf0 [ 56.131329] arch_send_call_function_ipi_mask+0x24/0x30 [ 56.135066] smp_call_function_many+0x2ac/0x348 [ 56.140098] smp_call_function+0x48/0x90 [ 56.144610] kick_all_cpus_sync+0x28/0x30 [ 56.148779] aarch64_insn_patch_text+0xb0/0xc0 [ 56.152688] arch_jump_label_transform+0x70/0x80 [ 56.157029] __jump_label_update+0x84/0xa0 [ 56.161800] jump_label_update+0xdc/0x110 [ 56.165706] static_key_slow_inc_cpuslocked+0xbc/0xe8 [ 56.169788] static_key_slow_inc+0x24/0x38 [ 56.174821] tracepoint_probe_register_prio+0x20c/0x278 [ 56.178816] tracepoint_probe_register+0x38/0x48 [ 56.183938] trace_event_reg+0x88/0x98 [ 56.188795] __ftrace_event_enable_disable+0x15c/0x2e8 [ 56.192358] __ftrace_set_clr_event_nolock+0xd4/0x130 [ 56.197478] system_enable_write+0xac/0xf0 [ 56.202600] __vfs_write+0x48/0x130 [ 56.206589] vfs_write+0xb0/0x1b8 [ 56.209974] SyS_write+0x5c/0xc8 [ 56.213446] __sys_trace_return+0x0/0x4 [ 56.216751] Code: d538d082 f944d401 ab020024 54000140 (b8626823) [ 56.220326] ---[ end trace 32d8a6bcfff49065 ]--- [ 56.226558] Kernel panic - not syncing: Fatal exception in interrupt [ 56.231256] SMP: stopping secondary CPUs [ 57.331332] SMP: failed to stop secondary CPUs 0-3 [ 57.331366] Kernel Offset: disabled [ 57.335011] CPU features: 0x0002005 [ 57.338396] Memory Limit: none [ 57.341888] ---[ end Kernel panic - not syncing: Fatal exception in interrupt

ref: https://qa-reports.linaro.org/lkft/linux-stable-rc-4.14-oe/build/v4.14.194-5...

https://lkft.validation.linaro.org/scheduler/job/1705703#L2155