| Message ID | 1429692989-10646-1-git-send-email-qiyaoltc@gmail.com |
|---|---|
| State | New |
| Headers | show |
diff --git a/gdb/testsuite/gdb.base/relativedebug.exp b/gdb/testsuite/gdb.base/relativedebug.exp index 621226b..b42dbf9 100644 --- a/gdb/testsuite/gdb.base/relativedebug.exp +++ b/gdb/testsuite/gdb.base/relativedebug.exp @@ -31,6 +31,17 @@ clean_restart ${binfile} runto_main +set test "info sharedlibrary" +gdb_test_multiple $test $test { + -re ".*\(\\*\)\[^\r\n\]*/libc\.so.*$gdb_prompt $" { + # Skip the test below if libc doesn't have debug info. + unsupported "libc doesn't have debug info" + return -1 + } + -re ".*$gdb_prompt $" { + } +} + # pause () -> SIGALRM -> handler () -> abort () gdb_test "continue" "Program received signal SIGABRT.*"
From: Yao Qi <yao.qi@linaro.org> 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: 2015-04-22 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. --- gdb/testsuite/gdb.base/relativedebug.exp | 11 +++++++++++ 1 file changed, 11 insertions(+)