From: Daniel Jacobowitz <drow@false.org>
To: Paul Hilfinger <hilfingr@gnat.com>
Cc: gdb@sources.redhat.com
Subject: Re: GDB interaction with sigwait under Redhat 9.0
Date: Wed, 12 May 2004 13:55:00 -0000 [thread overview]
Message-ID: <20040512135530.GA25764@nevyn.them.org> (raw)
In-Reply-To: <20040512083348.55D63F2D8B@nile.gnat.com>
On Wed, May 12, 2004 at 04:33:48AM -0400, Paul Hilfinger wrote:
>
> I recently submitted PR threads/1641 concerning a problem we seem to
> be having with Redhat 9.0 (Linux ... 2.4.21-9.ELsmp #1 SMP Thu Jan 8
> 17:08:56 EST 2004 i686 i686 i386 GNU/Linux). It appears that on that
> system, there is a new, malign interaction of sigwait in the inferior
> with ptrace. First, GDB (head version from about mid-April), no
> longer sees signals sent to an inferior that is waiting on sigwait. Second,
> GDB's manipulation with the inferior causes sigwaits (at least on
> pthreaded programs) to continue with a non-zero status code (EINTR to
> be precise). Does anyone know anything about this rather drastic change
> in sigwait's behavior? I intend to submit a GNU/Linux bug report, unless
> someone knows a good reason for this new (apparently undocumented) spec.
The EINTR bit is fairly typical; it is probably the C library's
obligation to hide it from you, or else the kernel's to not deliver it
in the first place, but that's a little tricky. However, you never
said what version of the Linux kernel you were using - it does not look
like 2.6 can produce this result. But then I don't see how an
unmodified 2.4 can either.
The inability to see signals received during sigwait is also a kernel
bug. Looking at the code, it replicates a portion of the path from
do_signal without duplicating the ptrace-related bits.
--
Daniel Jacobowitz
next prev parent reply other threads:[~2004-05-12 13:55 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-05-12 8:33 Paul Hilfinger
2004-05-12 13:55 ` Daniel Jacobowitz [this message]
2004-05-13 9:33 ` Paul Hilfinger
2004-05-13 13:30 ` Daniel Jacobowitz
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