www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.bugs - [Issue 3208] New: setAssertHandler leads to segfault

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3208

           Summary: setAssertHandler leads to segfault
           Product: D
           Version: 2.030
          Platform: Other
        OS/Version: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: druntime
        AssignedTo: sean invisibleduck.org
        ReportedBy: lutger.blijdestijn gmail.com


The following code produces a segmentation fault. If compiled with -g this does
not occur.

import core.exception;

void handleAssertion(string file, size_t line, string msg = null) {};

static this() 
{ 
    setAssertHandler( &handleAssertion  ); 
}

void main() 
{ 
    assert(false); 
}

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Jul 24 2009
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3208


nfxjfg gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |nfxjfg gmail.com





My guess is that the compiler generates code, that doesn't expect
assert(false); to actually return normally.

The assert(false) statement generates the following function, which apparently
does the job of actually calling _d_assert, if the assertion condition wasn't
fulfilled:

080495a8 <_D2rt8__assertFiZv>:
 80495a8:       55                      push   ebp
 80495a9:       8b ec                   mov    ebp,esp
 80495ab:       50                      push   eax
 80495ac:       ff 35 98 6a 06 08       push   DWORD PTR ds:0x8066a98
 80495b2:       ff 35 94 6a 06 08       push   DWORD PTR ds:0x8066a94
 80495b8:       e8 a7 8e 00 00          call   8052464 <_d_assert>
 80495bd:       5d                      pop    ebp
 80495be:       c3                      ret    

As you can see, the stack after the call _d_assert isn't cleaned up. There are
still 3 parameters on the stack. As far as I know, it's the caller's job to
clean up (_d_assert is declared as extern(C) and this is on Linux). This means
the ret statement would jump to a bogus memory position.

But I could be wrong.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Jul 25 2009
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3208


Jarrett Billingsley <jarrett.billingsley gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jarrett.billingsley gmail.c
                   |                            |om





2009-07-25 07:55:57 PDT ---


 My guess is that the compiler generates code, that doesn't expect
 assert(false); to actually return normally.


You're probably right.  In my investigation I found the only way to *not* have
it crash was to throw an exception from the assertion handler.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Jul 25 2009
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3208






PDT ---
Yeah, DMD requires the assert handler to throw.  It's not an optimization I'm
particularly fond of, but it doesn't seem likely that this will change.  Since
this isn't a library issue, I suggest either closing the ticket or redirecting
it to Walter as an enhancement request for DMD.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Jul 25 2009
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=3208


Lutger <lutger.blijdestijn gmail.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|druntime                    |DMD
         AssignedTo|sean invisibleduck.org      |nobody puremagic.com
           Severity|normal                      |enhancement





PDT ---
Allright, I'd like to propose this as an enhancement.

-- 
Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
Jul 27 2009