Re: [emacs-master] Frequent freezes on macOS

[Doug Davis]

I've been able to reproduce the crash.

Eli Zaretskii <eliz@gnu.org> writes:

> Can you attach a debugger to Emacs when it freezes, and show the
> C-level backtrace?

Here's my novice debugger attempt (apologies if it's not helpful); first
after compiling with -O3 -g3:

ddavis@charm ~/software/repos/emacs (HEAD detached at 8f0ce42d3e) $ lldb 
src/emacs
(lldb) target create "src/emacs"
Current executable set to '/Users/ddavis/software/repos/emacs/src/emacs' 
(arm64).
(lldb) run
Process 28189 launched: '/Users/ddavis/software/repos/emacs/src/emacs' (arm64)
2021-01-19 11:30:20.006114-0500 emacs[28189:1400131] fopen failed for data 
file: errno = 2 (No such file or directory)
2021-01-19 11:30:20.006128-0500 emacs[28189:1400131] Errors found! Invalidating 
cache...
Process 28189 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGTERM
    frame #0: 0x000000018cc708d0 libsystem_kernel.dylib`read + 8
libsystem_kernel.dylib`read:
->  0x18cc708d0 <+8>:  b.lo   0x18cc708f0               ; <+40>
    0x18cc708d4 <+12>: pacibsp 
    0x18cc708d8 <+16>: stp    x29, x30, [sp, #-0x10]!
    0x18cc708dc <+20>: mov    x29, sp
Target 0: (emacs) stopped.
(lldb) bt
Process 28189 exited with status = 0 (0x00000000) Terminated due to signal 9
warning: could not execute support code to read Objective-C class data in the 
process. This may reduce the quality of type information available.
* thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGTERM
  * frame #0: 0x000000018cc708d0 libsystem_kernel.dylib`read + 8
    frame #1: 0x00000001000de1c8 emacs`emacs_read [inlined] 
emacs_intr_read(fd=17, buf=0x000000016fdfbb3f, nbyte=<no summary available>, 
interruptible=<no summary available>) at sysdep.c:2486:16 [opt]
    frame #2: 0x00000001000de1b8 emacs`emacs_read(fd=<no summary available>, 
buf=<unavailable>, nbyte=<no summary available>) at sysdep.c:2500 [opt]

and after compiling with -O0 -g3:

ddavis@charm ~/software/repos/emacs (HEAD detached at 8f0ce42d3e) $ lldb 
src/emacs
(lldb) target create "src/emacs"
Current executable set to '/Users/ddavis/software/repos/emacs/src/emacs' 
(arm64).
(lldb) run
Process 60350 launched: '/Users/ddavis/software/repos/emacs/src/emacs' (arm64)
Process 60350 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGTERM
    frame #0: 0x000000018cc708d0 libsystem_kernel.dylib`read + 8
libsystem_kernel.dylib`read:
->  0x18cc708d0 <+8>:  b.lo   0x18cc708f0               ; <+40>
    0x18cc708d4 <+12>: pacibsp 
    0x18cc708d8 <+16>: stp    x29, x30, [sp, #-0x10]!
    0x18cc708dc <+20>: mov    x29, sp
Target 0: (emacs) stopped.
(lldb) thread list
Process 60350 stopped
* thread #1: tid = 0x1764c3, 0x000000018cc708d0 libsystem_kernel.dylib`read + 
8, queue = 'com.apple.main-thread', stop reason = signal SIGTERM
  thread #4: tid = 0x1764f7, 0x000000018cc77e04 libsystem_kernel.dylib`poll + 
8, name = 'gmain'
  thread #5: tid = 0x176508, 0x000000018cc7a0e8 libsystem_kernel.dylib`__select 
+ 8
  thread #6: tid = 0x176520, 0x000000018cc6fce8 
libsystem_kernel.dylib`mach_msg_trap + 8, name = 'com.apple.NSEventThread'
  thread #36: tid = 0x178ca1, 0x000000018cc719c4 
libsystem_kernel.dylib`__workq_kernreturn + 8
  thread #38: tid = 0x1790f4, 0x000000018cc719c4 
libsystem_kernel.dylib`__workq_kernreturn + 8
(lldb) thread backtrace all
Process 60350 exited with status = 0 (0x00000000) Terminated due to signal 9
warning: could not execute support code to read Objective-C class data in the 
process. This may reduce the quality of type information available.
* thread #1, queue = 'com.apple.main-thread', stop reason = signal SIGTERM
  * frame #0: 0x000000018cc708d0 libsystem_kernel.dylib`read + 8
    frame #1: 0x0000000100170254 emacs`emacs_intr_read(fd=17, 
buf=<unavailable>, nbyte=<no summary available>, interruptible=<no summary 
available>) at sysdep.c:2486:16
  thread #4, name = 'gmain'
    frame #0: 0xffffffffffffffff 
  thread #5
    frame #0: 0xffffffffffffffff 
  thread #6, name = 'com.apple.NSEventThread'
    frame #0: 0xffffffffffffffff 
  thread #36
    frame #0: 0xffffffffffffffff 
  thread #38
    frame #0: 0xffffffffffffffff