[Bug tapsets/26843] New: print_ubacktrace_fileline is broken on master

[Bug tapsets/26843] New: print_ubacktrace_fileline is broken on master

[agentzh at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=26843

            Bug ID: 26843
           Summary: print_ubacktrace_fileline is broken on master
           Product: systemtap
           Version: unspecified
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: tapsets
          Assignee: systemtap at sourceware dot org
          Reporter: agentzh at gmail dot com
  Target Milestone: ---

Seems like `print_ubacktrace_fileline` is broken on Ubuntu 20 x86_64 (kernel
Linux ubuntu20-pkg 5.4.0-24-generic #28-Ubuntu SMP Thu Apr 9 22:16:42 UTC 2020
x86_64 x86_64 x86_64 GNU/Linux) It can be reproduced with the following minimal
example using the latest systemtap git master (commit 9102da049a):

First prepare the target C program:

```C
int main(void) {
    return 0;
}
```

Compile it to generate executable file `./a.out`:

```
gcc -g a.c
```

Prepare the following simple .stp file:

```
function foo() {
    print_ubacktrace_fileline();
}

probe process.function("main") {
    foo();
    exit();
}
```

And run both:

```
$ stap a.stp -c ./a.out
WARNING: Kernel function symbol table missing [man warning::symbols]
 0x55cfc28cd131 : main+0x8/0x17 [/home/agentzh/git/systemtap-plus/a.out]
 0x7f59d5d7d0b3 [/usr/lib/x86_64-linux-gnu/libc-2.31.so+0x270b3/0x1f2000]
WARNING: Missing unwind data for a module, rerun with 'stap -d
/usr/lib/x86_64-linux-gnu/libc-2.31.so'
```

No file name or line numbers in the output. (The warnings can be safely ignored
since they are not relevant here).

For comparison on CentOS 6, for example, it works fine using the same version
of stap:

```
$ stap a.stp -c ./a.out
 0x4004b6 : main+0x4/0xe at /home/agentzh/git/systemtap/a.c:2
[/home/agentzh/git/systemtap/a.out]
 0x7fe4d3140d20 [/lib64/libc-2.12.so+0x1ed20/0x394000]
WARNING: Missing unwind data for a module, rerun with 'stap -d
/lib64/libc-2.12.so'
```

-- 
You are receiving this mail because:
You are the assignee for the bug.

[Bug tapsets/26843] print_ubacktrace_fileline is broken on master

[wcohen at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=26843

William Cohen <wcohen at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |wcohen at redhat dot com
   Last reconfirmed|                            |2024-01-11
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #1 from William Cohen <wcohen at redhat dot com> ---
When trying this on x86_64 RHEL8, RHEL9, and Fedora 39 with a current git
checkout of systemtap (023ec371b183c1) the output included the file and line
number:

$ sudo ../install/bin/stap a.stp -c
/home/wcohen/systemtap_write/systemtap/a.out
 0x40110a : main+0x4/0xe at /home/wcohen/systemtap_write/systemtap/a.c:2
[/home/wcohen/systemtap_write/systemtap/a.out]
 0x7f26492ee14a [/usr/lib64/libc.so.6+0x2814a/0x1e2000]
WARNING: Missing unwind data for a module, rerun with 'stap -d
/usr/lib64/libc.so.6'

However, on x86_64 unbuntu 20.04 I do see the issue reported with the same git
checkout of systemtap:

$ sudo ../install/bin/stap a.stp  -c
/home/william/systemtap_write/systemtap/a.out
 0x55facda6a131 : main+0x8/0x17 [/home/william/systemtap_write/systemtap/a.out]
 0x7f3804b72083 [/usr/lib/x86_64-linux-gnu/libc-2.31.so+0x24083/0x1f2000]
WARNING: Missing unwind data for a module, rerun with 'stap -d
/usr/lib/x86_64-linux-gnu/libc-2.31.so'

On RHEL8 dwarf4 is being used and on RHEL9/Fedora 39 dwarf 5.  Ubuntu 20.04 is
using dwarf 4.  I was able to run the unbuntu generated a.out on f39.  The
output is missing the expected filename and line number. Using "llvm-objdump
--line-numbers <object_file>" on f39 it appears that llvm-objdump can find the
line numbers:

f39 generated binary:

0000000000401106 <main>:
; main():
; /home/wcohen/systemtap_write/systemtap/a.c:1
  401106: 55                            pushq   %rbp
  401107: 48 89 e5                      movq    %rsp, %rbp
; /home/wcohen/systemtap_write/systemtap/a.c:2
  40110a: b8 00 00 00 00                movl    $0x0, %eax
; /home/wcohen/systemtap_write/systemtap/a.c:3
  40110f: 5d                            popq    %rbp
  401110: c3                            retq



ubuntu 20.04 generated binary:

0000000000001129 <main>:
; main():
; /home/william/systemtap_write/systemtap/a.c:1
    1129: f3 0f 1e fa                   endbr64
    112d: 55                            pushq   %rbp
    112e: 48 89 e5                      movq    %rsp, %rbp
; /home/william/systemtap_write/systemtap/a.c:2
    1131: b8 00 00 00 00                movl    $0x0, %eax
; /home/william/systemtap_write/systemtap/a.c:3
    1136: 5d                            popq    %rbp
    1137: c3                            retq
    1138: 0f 1f 84 00 00 00 00 00       nopl    (%rax,%rax)

-- 
You are receiving this mail because:
You are the assignee for the bug.

[Bug tapsets/26843] print_ubacktrace_fileline is broken on master

[mcermak at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=26843

Martin Cermak <mcermak at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|systemtap at sourceware dot org    |mcermak at redhat dot com
                 CC|                            |mcermak at redhat dot com

-- 
You are receiving this mail because:
You are the assignee for the bug.