linux-kernel - Re: Fix signalfd interaction with thread-private signals

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <alpine.LFD.0.98.0706211133350.3593@woody.linux-foundation.org>
Date:	Thu, 21 Jun 2007 11:35:21 -0700 (PDT)
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Oleg Nesterov <oleg@...sign.ru>
cc:	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	Davide Libenzi <davidel@...ilserver.org>,
	Nicholas Miell <nmiell@...cast.net>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: Fix signalfd interaction with thread-private signals



On Thu, 21 Jun 2007, Oleg Nesterov wrote:
> 
> Yes, the target thread is the one that caused the SIGSEGV, it sends the signal
> to itself. entry.S:ret_from_exception should notice this signal and _dequeue_
> it, no? This signal could be stealed by signal(SIG_IGN) which runs after it
> was delivered.

Right. But it will dequeue it by *taking* it.

IOW, this has absolutely nothing to do with signalfd.

That's all I mean.

> My point was that it is _possible_ to steal a thread-local SIGSEGV even without
> signalfd, nothing bad should happen.

That makes no sense.

You don't "steal" it. You take it. It's what SIGSEGV (and _any_ signal) 
has always been about. You get the signal, enter the signal handler, and 
handle it. 

No "stealing". No signalfd, no *nothing*. Just normal signal behaviour.

		Linus
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/