----- Original Message -----
> Hi Dave
>
> I have experienced some problems in the bt command for ARM64. It seems that
> the test in arm64_print_exception_frame in arm64.c if the task is running in
> 32 or 64-bit mode in userland does not work. It "always" becomes 32-bit
> mode. Example:
>
> crash> bt 1
> PID: 1 TASK: ffffffe1f90f8000 CPU: 2 COMMAND: "init"
> #0 [ffffffe1f9103c80] __switch_to at ffffff85b6a862f8
> #1 [ffffffe1f9103ca0] __schedule at ffffff85b7b0d9b0
> #2 [ffffffe1f9103d00] schedule at ffffff85b7b0df28
> #3 [ffffffe1f9103d20] schedule_hrtimeout_range_clock at ffffff85b7b11308
> #4 [ffffffe1f9103da0] schedule_hrtimeout_range at ffffff85b7b11320
> #5 [ffffffe1f9103db0] sys_epoll_wait at ffffff85b6c394c8
> #6 [ffffffe1f9103e70] sys_epoll_pwait at ffffff85b6c396fc
> #7 [ffffffe1f9103ed0] el0_svc_naked at ffffff85b6a8312c
> PC: 00000004 LR: 00000000 SP: 00000000 PSTATE: 00000016
> X12: 00546694 X11: 3431206c616e6769 X10: 00546338 X9: 00000000
> X8: 00000112 X7: dfdab819254dd1e8 X6: 00000016 X5: 0000000a
> X4: 00000031 X3: 00000008 X2: 00000000 X1: ffffffff
> X0: 00000001
>
> The register values are:
> r0: 4 r1: 7ff0b27f90
> r2: 1 r3: ffffffff
> r4: 0 r5: 8
> r6: 31 r7: a
> r8: 16 r9: dfdab819254dd1e8
> r10: 112 r11: 0
> r12: 546338 r13: 3431206c616e6769
> r14: 546694 r15: 0
> r16: 0 r17: f04245b7
> r18: 51f2a993 r19: 5783c0
> r20: 415254 r21: 527a5c
> r22: 527e04 r23: ffffffff
> r24: ffffffff r25: 576000
> r26: 578000 r27: 578000
> r28: 3e8 fp: 7ff0b27ec0
> lr: 4f4f24 sp: 7ff0b27eb0
> pc: 4fb8d4 psr: 40000000
>
> I have unfortunately not had the time to look for a solution, so I just want
> to report what I have seen. The kernel running in the example above is
> 4.4.74 and I have seen the same problem for a 4.9.40 kernel.
>
> Jan
Yeah, even the functions that do show 64-bit user mode exception frames
appear to have invalid contents. It looks like the pt_regs is not at the
same fixed location on the stack where it has always been, i.e., as it gets
set here unconditionally at the bottom of arm64_back_trace_cmd():
complete_user:
exception_frame = bt->stacktop - USER_EFRAME_OFFSET;
arm64_print_exception_frame(bt, exception_frame, USER_MODE, ofp);
Thanks,
Dave
--
Crash-utility mailing list
Crash-utility@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/crash-utility
