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Re: stepping over longjmp
- From: Daniel Jacobowitz <drow at false dot org>
- To: Nick Roberts <nickrob at snap dot net dot nz>
- Cc: gdb at sources dot redhat dot com
- Date: Fri, 4 Aug 2006 09:19:13 -0400
- Subject: Re: stepping over longjmp
- References: <17619.308.218261.761948@kahikatea.snap.net.nz>
On Fri, Aug 04, 2006 at 08:11:32PM +1200, Nick Roberts wrote:
>
> With current CVS GDB and Fedora Core 5 i686 i386 GNU/Linux (2.6.17-1.2157 but
> also 2.6.15) when I try to step over longjmp (using next) I get the following
> error:
>
> Warning:
> Cannot insert breakpoint -59.
> Error accessing memory address 0x226092c5: Input/output error.
>
> ISTR that this was also the case with FC4 and have only recently realised that
> you can step usefully step over a longjmp call after trying it on Mandrake 9
> (2.4.19)
>
> Is this a known kernel problem or a bug in GDB?
Has nothing to do with the kernel. I imagine that this is the problem
I discussed on this list a while ago, CC'd to libc-alpha; glibc now
uses a canary in the jmp_buf which GDB has no way to access.
Does export LD_POINTER_GUARD=0 make a difference?
--
Daniel Jacobowitz
CodeSourcery