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Hi, I see the fail in gdb.base/relativedebug.exp on aarch64 box on which glibc doesn't have debug info, bt^M #0 0x0000002000061a88 in raise () from /lib/aarch64-linux-gnu/libc.so.6^M #1 0x0000002000064efc in abort () from /lib/aarch64-linux-gnu/libc.so.6^M #2 0x0000000000400640 in handler (signo=14) at ../../../binutils-gdb/gdb/testsuite/gdb.base/relativedebug.c:25^M #3 <signal handler called>^M #4 0x00000020000cc478 in ?? () from /lib/aarch64-linux-gnu/libc.so.6^M #5 0x0000000000400664 in main () at ../../../binutils-gdb/gdb/testsuite/gdb.base/relativedebug.c:32^M (gdb) FAIL: gdb.base/relativedebug.exp: pause found in backtrace if glibc has debug info, this test doesn't fail. In sysdeps/unix/sysv/linux/generic/pause.c, __libc_pause calls __syscall_pause, static int __syscall_pause (void) { sigset_t set; int rc = INLINE_SYSCALL (rt_sigprocmask, 4, SIG_BLOCK, NULL, &set, _NSIG / 8); if (rc == 0) rc = INLINE_SYSCALL (rt_sigsuspend, 2, &set, _NSIG / 8); return rc; } int __libc_pause (void) { if (SINGLE_THREAD_P) return __syscall_pause (); <--- tail call int oldtype = LIBC_CANCEL_ASYNC (); int result = __syscall_pause (); LIBC_CANCEL_RESET (oldtype); return result; } and GDB unwinder is confused by the GCC optimized code, (gdb) disassemble pause Dump of assembler code for function pause: 0x0000007fb7f274c4 <+0>: stp x29, x30, [sp,#-32]! 0x0000007fb7f274c8 <+4>: mov x29, sp 0x0000007fb7f274cc <+8>: adrp x0, 0x7fb7fd2000 0x0000007fb7f274d0 <+12>: ldr w0, [x0,#364] 0x0000007fb7f274d4 <+16>: stp x19, x20, [sp,#16] 0x0000007fb7f274d8 <+20>: cbnz w0, 0x7fb7f274e8 <pause+36> 0x0000007fb7f274dc <+24>: ldp x19, x20, [sp,#16] 0x0000007fb7f274e0 <+28>: ldp x29, x30, [sp],#32 0x0000007fb7f274e4 <+32>: b 0x7fb7f27434 <---- __syscall_pause 0x0000007fb7f274e8 <+36>: bl 0x7fb7f5e080 Note that the program stops in __syscall_pause, but its symbol is stripped in glibc, so GDB doesn't know where the program stops. __syscall_pause is a tail call in __libc_pause, so it returns to main instead of __libc_pause. As a result, the backtrace is like, #0 0x0000007fb7ebca88 in raise () from /lib/aarch64-linux-gnu/libc.so.6 #1 0x0000007fb7ebfefc in abort () from /lib/aarch64-linux-gnu/libc.so.6 #2 0x0000000000400640 in handler (signo=14) at ../../../binutils-gdb/gdb/testsuite/gdb.base/relativedebug.c:25 #3 <signal handler called> #4 0x0000007fb7f27478 in ?? () from /lib/aarch64-linux-gnu/libc.so.6 <-- [in __syscall_pause] #5 0x0000000000400664 in main () at ../../../binutils-gdb/gdb/testsuite/gdb.base/relativedebug.c:32 looks GDB does nothing wrong here. I looked back at the test case gdb.base/relativedebug.exp, which was added https://sourceware.org/ml/gdb-patches/2006-10/msg00305.html This test was indented to test the problem that "backtraces no longer display some libc functions" after separate debug info is installed. IOW, it makes few sense to test against libc which doesn't have debug info at all, such as my case. This patch is to tweak the test case to catch the output of "info shared", if "(*)" is found for libc.so, which means libc doesn't have debug info, then skip the test. gdb/testsuite: 2015-04-30 Yao Qi <yao.qi@linaro.org> * gdb.base/relativedebug.exp: Invoke gdb command "info sharedlibrary", and if libc.so doesn't have debug info, skip the test.
README for GNU development tools This directory contains various GNU compilers, assemblers, linkers, debuggers, etc., plus their support routines, definitions, and documentation. If you are receiving this as part of a GDB release, see the file gdb/README. If with a binutils release, see binutils/README; if with a libg++ release, see libg++/README, etc. That'll give you info about this package -- supported targets, how to use it, how to report bugs, etc. It is now possible to automatically configure and build a variety of tools with one command. To build all of the tools contained herein, run the ``configure'' script here, e.g.: ./configure make To install them (by default in /usr/local/bin, /usr/local/lib, etc), then do: make install (If the configure script can't determine your type of computer, give it the name as an argument, for instance ``./configure sun4''. You can use the script ``config.sub'' to test whether a name is recognized; if it is, config.sub translates it to a triplet specifying CPU, vendor, and OS.) If you have more than one compiler on your system, it is often best to explicitly set CC in the environment before running configure, and to also set CC when running make. For example (assuming sh/bash/ksh): CC=gcc ./configure make A similar example using csh: setenv CC gcc ./configure make Much of the code and documentation enclosed is copyright by the Free Software Foundation, Inc. See the file COPYING or COPYING.LIB in the various directories, for a description of the GNU General Public License terms under which you can copy the files. REPORTING BUGS: Again, see gdb/README, binutils/README, etc., for info on where and how to report problems.