[DragonFlyBSD - Bug #2615] panic while running gdb test suite

[Nicolas Thery via Redmine]

Issue #2615 has been updated by nthery.


Hello,

It tries to ptrace(PT_ATTACH) to process 0 (the swapper) and crashes
during the reparenting because process 0 has no parent.  There is
definitely a bug in the kernel which should return an error.  This is
maybe also symptomatic of a bug in gdb which shouldn't try to debug
process 0 (or is it a negative test checking how gdb reacts when
failing to attach to a process?)

I'm tempted to make ptrace(PT_ATTACH) return EINVAL for all system
processes to prevent this as a reckon ptrace(2) is intended to debug
userlang only and attaching to kernel processes, besides security
issues, is deadlock-prone.  I'm checking the literature and other
implementations to confirm this is the way to go.

Cheers,
Nicolas

On 17 December 2013 23:25,  <bugtracker-admin at leaf.dragonflybsd.org> wrote:
>
> Issue #2615 has been reported by phma.
>
> ----------------------------------------
> Bug #2615: panic while running gdb test suite
> http://bugs.dragonflybsd.org/issues/2615
>
> * Author: phma
> * Status: New
> * Priority: High
> * Assignee:
> * Category:
> * Target version:
> ----------------------------------------
> see https://github.com/DragonFlyBSD/DPorts/wiki/Run-GDB-testsuite
>
> I ran the testsuite on gdb 7.6.1 and it crashed partway through. This is as far as it got:
>
> Running ./gdb.base/fileio.exp ...
> FAIL: gdb.base/fileio.exp: Open for write but no write permission returns
> EACCES
> FAIL: gdb.base/fileio.exp: Unlinking a file in a directory w/o write access
> returns EACCES
> Running ./gdb.base/gcore-relro.exp ...
> Running ./gdb.base/huge.exp ...
> Running ./gdb.base/find.exp ...
> Running ./gdb.base/ctxobj.exp ...
> Running ./gdb.base/cond-eval-mode.exp ...
> Running ./gdb.base/arrayidx.exp ...
> Running ./gdb.base/eval-skip.exp ...
> Running ./gdb.base/attach.exp ...
>
> It crashed in the same place both times. The kernel dumps are numbers 2 and 3 in leaf:/home/phma/crash/zyxomma/. I need this fixed so that I can fix the thread bug in gdb.
>
>
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----------------------------------------
Bug #2615: panic while running gdb test suite
http://bugs.dragonflybsd.org/issues/2615#change-11680

* Author: phma
* Status: New
* Priority: High
* Assignee: 
* Category: 
* Target version: 
----------------------------------------
see https://github.com/DragonFlyBSD/DPorts/wiki/Run-GDB-testsuite

I ran the testsuite on gdb 7.6.1 and it crashed partway through. This is as far as it got:

Running ./gdb.base/fileio.exp ...
FAIL: gdb.base/fileio.exp: Open for write but no write permission returns 
EACCES
FAIL: gdb.base/fileio.exp: Unlinking a file in a directory w/o write access 
returns EACCES
Running ./gdb.base/gcore-relro.exp ...
Running ./gdb.base/huge.exp ...
Running ./gdb.base/find.exp ...
Running ./gdb.base/ctxobj.exp ...
Running ./gdb.base/cond-eval-mode.exp ...
Running ./gdb.base/arrayidx.exp ...
Running ./gdb.base/eval-skip.exp ...
Running ./gdb.base/attach.exp ...

It crashed in the same place both times. The kernel dumps are numbers 2 and 3 in leaf:/home/phma/crash/zyxomma/. I need this fixed so that I can fix the thread bug in gdb.



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