[Crash-utility] arm64: odd backtrace?

Dave, When I ran "bt" against a process running in a user mode, I got an odd backtrace result: ===8<=== crash> ps ... 1325 2 1 ffff800021089900 IN 0.0 0 0 [kworker/u16:0] crash> bt 1324 PID: 1324 TASK: ffff80002018be80 CPU: 2 COMMAND: "dhry" ffff800022f6ae08: ffff00000812ae44 (crash_save_cpu on IRQ stack) #0 [ffff800022f6ae10] crash_save_cpu at ffff00000812ae44 #1 [ffff800022f6ae60] handle_IPI at ffff00000808e718 #2 [ffff800022f6b020] gic_handle_irq at ffff0000080815f8 #3 [ffff800022f6b050] el0_irq_naked at ffff000008084c4c pt_regs: ffff800022f6af60 PC: ffffffffffffffff [unknown or invalid address] LR: ffff800020107ed0 [unknown or invalid address] SP: 0000000000000000 PSTATE: 004016a4 X29: ffff000008084c4c X28: ffff800022f6b080 X27: ffff000008e60c54 X26: ffff800020107ed0 X25: 0000000000001fff X24: 0000000000000003 X23: ffff0000080815f8 X22: ffff800022f6b040 X21: 0000000000000000 X20: ffff000008bce000 X19: ffff00000808e758 X18: ffff800022f6b010 X17: ffff00000808a820 X16: ffff800022f6aff0 X15: 0000000000000000 X14: 0000000000000000 X13: 0000000000000000 X12: 0000000000402138 X11: ffff000008675850 X10: ffff800022f6afe0 X9: 0000000000000000 X8: ffff800022f6afc0 X7: 0000000000000000 X6: 0000000000000000 X5: 0000000000000000 X4: 0000000000000001 X3: 0000000000000000 X2: 0000000000493000 X1: 0000000000498000 X0: ffffffffffffffff ORIG_X0: 0000000020000000 SYSCALLNO: 4021f0 bt: WARNING: arm64_unwind_frame: on IRQ stack: oriq_sp: ffff800020107ed0 fp: 0 (?) pt_regs: ffff800020107ed0 PC: 00000000004016a4 LR: 00000000004016a4 SP: 0000ffffc10c40a0 X29: 0000ffffc10c40a0 X28: 0000000000000000 X27: 0000000000000000 X26: 0000000000000000 X25: 0000000000402138 X24: 00000000004021f0 X23: 0000000000000000 X22: 0000000000000000 X21: 00000000004001a0 X20: 0000000000000000 X19: 0000000000000000 X18: 0000000000000000 X17: 0000000000000001 X16: 0000000000000000 X15: 0000000000493000 X14: 0000000000498000 X13: ffffffffffffffff X12: 0000000000000005 X11: 000000000000001e X10: 0101010101010101 X9: fffffffff59a9190 X8: 7f7f7f7f7f7f7f7f X7: 1f535226301f2b4c X6: 00000003001d1000 X5: 00101d0003000000 X4: 0000000000000000 X3: 4952545320454d4f X2: 0000000010c35b40 X1: 0000000000000011 X0: 0000000010c35b40 ORIG_X0: 0000000000498700 SYSCALLNO: ffffffffffffffff PSTATE: 20000000 ===>8=== * PC, LR and SP look wrong. I don't know how those pt_regs values were derived. * The message, "WARNING: arm64_unwind_frame: on IRQ stack: oriq_sp: ffff800020107ed0 fp: 0 (?)" should be refined. Apparently, in this case, the process is running in a user mode, and so there is no normal kernel stack. Thanks, -Takahiro AKASHI