[Bug 1848200] Re: gdb not stopping on breakpoint in a 32-bit program

[dann frazier]

** Description changed:

- After upgrading gdb from 8.1-0ubuntu3 to 8.1-0ubuntu3.1, gdb does not
- stop on breakpoint when running a 32-bit application (on 64-bit Ubuntu).
+ [Impact]
+ After upgrading gdb from 8.1-0ubuntu3 to 8.1-0ubuntu3.1, gdb does not stop 
+ on breakpoint when running a 32-bit application (on 64-bit Ubuntu). 
+ 
+ [Test Case]
  This can be reproduced with a simple “hello world” program:
  
- $ cat hello.c 
+ $ cat hello.c
  #include <stdio.h>
  int main()
  {
-    // printf() displays the string inside quotation
-    printf("Hello, World!");
-    return 0;
+    // printf() displays the string inside quotation
+    printf("Hello, World!");
+    return 0;
  }
  $ gcc -ggdb -m32 hello.c
  $ gdb a.out
  (gdb) b hello.c:5
  Breakpoint 1 at 0x536: file hello.c, line 5.
  (gdb) run
- Starting program: /home/user/sandbox/a.out 
+ Starting program: /home/user/sandbox/a.out
  warning: Breakpoint address adjusted from 0xf7fd9be0 to 0xfffffffff7fd9be0.
  warning: Breakpoint address adjusted from 0xf7fda195 to 0xfffffffff7fda195.
  warning: Breakpoint address adjusted from 0xf7fdbd1c to 0xfffffffff7fdbd1c.
  warning: Breakpoint address adjusted from 0xf7fdb924 to 0xfffffffff7fdb924.
  warning: Breakpoint address adjusted from 0xf7fe99b3 to 0xfffffffff7fe99b3.
  warning: Breakpoint address adjusted from 0xf7fea401 to 0xfffffffff7fea401.
  warning: Breakpoint address adjusted from 0xf7fea706 to 0xfffffffff7fea706.
  
  --- (and not stopping nor outputting the text…) ---
  
- It works well with a 64-bit build (leaving out the gcc’s -m32 option).
+ [Regression Risk]
+ Test case ran on arm64 and regression tested on amd64/i386.
  
- This problem has been already discussed on:
- https://stackoverflow.com/questions/58225562/how-to-fix-hang-in-gdb-in-
- ld-linux-so-2-when-running-a-32-bit-executable-on-a-64
- 
- ProblemType: Bug
- DistroRelease: Ubuntu 18.04
- Package: gdb 8.1-0ubuntu3.1
- ProcVersionSignature: Ubuntu 4.15.0-65.74-generic 4.15.18
- Uname: Linux 4.15.0-65-generic x86_64
- ApportVersion: 2.20.9-0ubuntu7.7
- Architecture: amd64
- CurrentDesktop: XFCE
- Date: Tue Oct 15 14:37:37 2019
- InstallationDate: Installed on 2015-12-08 (1407 days ago)
- InstallationMedia: Ubuntu-Server 14.04.3 LTS "Trusty Tahr" - Beta amd64 (20150805)
- SourcePackage: gdb
- UpgradeStatus: Upgraded to bionic on 2019-06-10 (127 days ago)
+ This regression was fixed on the upstream gdb-8.1 branch within a few
+ weeks of the breakage back in May 2018. Since then there have been no
+ other fixes in this area on that branch, implying this fixed the issue
+ and there were no further regressions discovered.

-- 
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https://bugs.launchpad.net/bugs/1848200

Title:
  gdb not stopping on breakpoint in a 32-bit program

Status in gdb package in Ubuntu:
  Invalid
Status in gdb source package in Bionic:
  In Progress
Status in gdb source package in Disco:
  New
Status in gdb source package in Eoan:
  Invalid
Status in gdb source package in Focal:
  Invalid

Bug description:
  [Impact]
  After upgrading gdb from 8.1-0ubuntu3 to 8.1-0ubuntu3.1, gdb does not stop 
  on breakpoint when running a 32-bit application (on 64-bit Ubuntu). 

  [Test Case]
  This can be reproduced with a simple “hello world” program:

  $ cat hello.c
  #include <stdio.h>
  int main()
  {
     // printf() displays the string inside quotation
     printf("Hello, World!");
     return 0;
  }
  $ gcc -ggdb -m32 hello.c
  $ gdb a.out
  (gdb) b hello.c:5
  Breakpoint 1 at 0x536: file hello.c, line 5.
  (gdb) run
  Starting program: /home/user/sandbox/a.out
  warning: Breakpoint address adjusted from 0xf7fd9be0 to 0xfffffffff7fd9be0.
  warning: Breakpoint address adjusted from 0xf7fda195 to 0xfffffffff7fda195.
  warning: Breakpoint address adjusted from 0xf7fdbd1c to 0xfffffffff7fdbd1c.
  warning: Breakpoint address adjusted from 0xf7fdb924 to 0xfffffffff7fdb924.
  warning: Breakpoint address adjusted from 0xf7fe99b3 to 0xfffffffff7fe99b3.
  warning: Breakpoint address adjusted from 0xf7fea401 to 0xfffffffff7fea401.
  warning: Breakpoint address adjusted from 0xf7fea706 to 0xfffffffff7fea706.

  --- (and not stopping nor outputting the text…) ---

  [Regression Risk]
  Test case ran on arm64 and regression tested on amd64/i386.

  This regression was fixed on the upstream gdb-8.1 branch within a few
  weeks of the breakage back in May 2018. Since then there have been no
  other fixes in this area on that branch, implying this fixed the issue
  and there were no further regressions discovered.

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