[Bug libc/31349] New: backtrace fails to look beyond null pointer when resolving stack (x86_64)

["daniel at mariadb dot org" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=31349

            Bug ID: 31349
           Summary: backtrace fails to look beyond null pointer when
                    resolving stack (x86_64)
           Product: glibc
           Version: 2.38
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: libc
          Assignee: unassigned at sourceware dot org
          Reporter: daniel at mariadb dot org
                CC: drepper.fsp at gmail dot com
  Target Milestone: ---

Created attachment 15352
  --> https://sourceware.org/bugzilla/attachment.cgi?id=15352&action=edit
bt.c

Using backtrace in a signal hander, a null pointer dereference is a typical
cause.

Backtrace stops at the null pointer and fails to show information of the higher
stack that caused it.

$ gcc -g -o /tmp/bt /tmp/bt.c

$ /tmp/bt
Obtained 2 stack frames.
/tmp/bt() [0x4011a2]
/lib64/libc.so.6(+0x3e9a0) [0x7f98f2b759a0]

Expected results closer to what gdb does:

$ gdb /tmp/bt
(gdb) bt
#0  0x0000000000000000 in ?? ()
#1  0x0000000000401235 in dummy_function () at /tmp/bt.c:35
#2  0x0000000000401250 in main () at /tmp/bt.c:42

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