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Re: [RFA] Fix internal error in wait_lwp (interrupted system call)
- From: Ulrich Weigand <uweigand at de dot ibm dot com>
- To: drow at false dot org (Daniel Jacobowitz)
- Cc: uweigand at de dot ibm dot com (Ulrich Weigand), gdb-patches at sources dot redhat dot com
- Date: Fri, 13 May 2005 14:36:55 +0200 (CEST)
- Subject: Re: [RFA] Fix internal error in wait_lwp (interrupted system call)
Daniel Jacobowitz wrote:
> I think that's because GDB mostly uses signal(). That automatically
> has SA_RESTART behavior, right?
Andreas Schwab wrote:
> Depends on whether signal() has BSD or SYSV semantics.
I wasn't completely certain how to verify this at the source code level,
so I simply checked via 'strace': and indeed the signal() library calls
performed by gdb are transformed to sigaction() system calls *with*
SA_RESTART set on my Linux system.
This is IMO yet another argument for using SA_RESTART with the explicit
sigaction calls in linux-nat.c as well.
Daniel Jacobowitz wrote:
> I'm just worried that this will
> require non-local fixes; the SIGCHLD handler was in the same file, but
> arbitrary other signal handlers could be at arbitrary places in GDB.
> Not handling EINTR from a library call which is allowed to return EINTR
> is, pedantically, always a bug.
>
> Perhaps we should make both changes.
As verifying correct EINTR handling everywhere appears to be a major
effort, and the simple SA_RESTART patch both fixes a serious problem,
and appears to be correct in any case, I'd argue for applying that
patch now, and maybe later on adding EINTR handling as required.
Bye,
Ulrich
--
Dr. Ulrich Weigand
Linux on zSeries Development
Ulrich.Weigand@de.ibm.com