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From: Xavier Roche <roche+kml2@exalead.com>
To: Nicholas Miell <nmiell@comcast.net>
Cc: Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: sigaction's ucontext_t with incorrect stack reference when	SA_SIGINFO is being used ?
Date: Wed, 24 Jan 2007 08:44:43 +0100	[thread overview]
Message-ID: <45B70E6B.40104@exalead.com> (raw)
In-Reply-To: <1169530677.2995.8.camel@entropy>

Nicholas Miell wrote:
> so if uc_stack doesn't point to the stack in use immediately prior to
> signal generation, this is a bug.

Looking at arch/i386/kernel/signal.c (and others) inside
setup_rt_frame(), the problem is pretty obvious:

err |= __put_user(current->sas_ss_sp, &frame_user->uc.uc_stack.ss_sp);
err |= __put_user(sas_ss_flags(regs->esp),
	&frame->uc.uc_stack.ss_flags);
err |= __put_user(current->sas_ss_size, &frame_user->uc.uc_stack.ss_size);

And of course, the ss_sp is NULL when no alternative stack is used.
Seems definitively a bug.

However, my reading of include/linux/sched.h and thread_info.h did not
enlighten me on the way to get the original thread's stack base and size.


      reply	other threads:[~2007-01-24  7:44 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-22  8:57 sigaction's ucontext_t with incorrect stack reference when SA_SIGINFO is being used ? Xavier Roche
2007-01-23  5:37 ` Nicholas Miell
2007-01-24  7:44   ` Xavier Roche [this message]

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