Re: Missing backtrace information on aarch64

[Phil Reid]

On 19/03/2020 01:45, Stephen Hemminger wrote:
> Trying to use libunwind on Arm64 and discovered that it is not working
> as expected. Only one function is printed.
>
> On x86 Debian 10 (1.2.1-9)
> $ ./bt
> ^\Signal Quit recevied
> #0 0x5640deb47308 (sigquit+0x29)
> #1 0x7f4337b8587f (killpg+0x40)
> #2 0x7f4337c146f4 (nanosleep+0x14)
> #3 0x7f4337c1462a (sleep+0x3a)
> #4 0x5640deb4732c (main+0x1f)
> #5 0x7f4337b7209b (__libc_start_main+0xeb)
> #6 0x564
>
>
> On Arm64
>
> # /tmp/bt
> ^\Signal Quit recevied
> #0 0xab9f2f927bf0 (sigquit+0x34)
> Aborted (core dumped)

I patched gcc libs with the following for an 32bit arm system to get more 
complete backtraces.


diff -Naur a/libsupc++/eh_terminate.cc b/libsupc++/eh_terminate.cc
--- a/libstdc++-v3/libsupc++/eh_terminate.cc    2019-02-28 14:31:50.951261183 
+0800
+++ b/libstdc++-v3/libsupc++/eh_terminate.cc    2019-02-28 14:32:42.040396849 
+0800
@@ -40,7 +40,7 @@
 using namespace __cxxabiv1;

 void
-__cxxabiv1::__terminate (std::terminate_handler handler) throw ()
+__cxxabiv1::__terminate (std::terminate_handler handler)
 {
   __try
     {
diff -Naur a/libsupc++/unwind-cxx.h b/libsupc++/unwind-cxx.h
--- a/libstdc++-v3/libsupc++/unwind-cxx.h       2019-02-28 14:31:50.949253953 
+0800
+++ b/libstdc++-v3/libsupc++/unwind-cxx.h       2019-02-28 14:32:53.073426806 
+0800
@@ -189,8 +189,7 @@

 // Invokes given handler, dying appropriately if the user handler was
 // so inconsiderate as to return.
-extern void __terminate(std::terminate_handler) throw ()
-  __attribute__((__noreturn__));
+extern void __terminate(std::terminate_handler);
 extern void __unexpected(std::unexpected_handler)
   __attribute__((__noreturn__));



--
Regards
Phil Reid