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From: Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Borislav Petkov <bp-Gina5bIWoIWzQB+pC5nmwQ@public.gmane.org>,
	Stas Sergeev <stsp-cmBhpYW9OiY@public.gmane.org>,
	Al Viro <viro-RmSDqhL/yNMiFSDQTTA3OLVCufUGDwFn@public.gmane.org>,
	Aleksa Sarai <cyphar-gVpy/LI/lHzQT0dZR+AlfA@public.gmane.org>,
	Amanieu d'Antras
	<amanieu-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Andrea Arcangeli
	<aarcange-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>,
	Brian Gerst <brgerst-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Denys Vlasenko <dvlasenk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	"Eric W. Biederman"
	<ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>,
	Frederic Weisbecker
	<fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
	Heinrich Schuchardt <xypron.glpk-Mmb7MZpHnFY@public.gmane.org>,
	Jason Low <jason.low2-VXdhtT5mjnY@public.gmane.org>,
	Josh Triplett <josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org>,
	Konstantin Khlebnikov
	<khlebnikov-XoJtRXgx1JseBXzfvpsJ4g@public.gmane.org>,
	Linus Torvalds
	<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Palmer Dabbelt <palmer-96lFi9zoCfxBDgjK7y7TUQ@public.gmane.org>,
	Paul Moore <pmoore-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Pavel Emelyanov <xemul@parallels.c>
Subject: Re: [PATCH 1/4] signals/sigaltstack: If SS_AUTODISARM, bypass on_sig_stack
Date: Wed, 4 May 2016 08:32:33 +0200	[thread overview]
Message-ID: <20160504063233.GB9499@gmail.com> (raw)
In-Reply-To: <c46bee4654ca9e68c498462fd11746e2bd0d98c8.1462296606.git.luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>


* Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org> wrote:

> If a signal stack is set up with SS_AUTODISARM, then the kernel
> inherently avoids incorrectly resetting the signal stack if signals
> recurse: the signal stack will be reset on the first signal
> delivery.  This means that we don't need check the stack pointer
> when delivering signals if SS_AUTODISARM is set.
> 
> This will make segmented x86 programs more robust: currently there's
> a hole that could be triggered if ESP/RSP appears to point to the
> signal stack but actually doesn't due to a nonzero SS base.
> 
> Signed-off-by: Stas Sergeev <stsp-cmBhpYW9OiY@public.gmane.org>

Presuably that SOB from Stas is stray, as there's no matching From: line?
I've removed it.

Thanks,

	Ingo

WARNING: multiple messages have this Message-ID (diff)
From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@kernel.org>
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	Borislav Petkov <bp@alien8.de>, Stas Sergeev <stsp@list.ru>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Aleksa Sarai <cyphar@cyphar.com>,
	"Amanieu d'Antras" <amanieu@gmail.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andy Lutomirski <luto@amacapital.net>,
	Brian Gerst <brgerst@gmail.com>,
	Denys Vlasenko <dvlasenk@redhat.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Heinrich Schuchardt <xypron.glpk@gmx.de>,
	Jason Low <jason.low2@hp.com>,
	Josh Triplett <josh@joshtriplett.org>,
	Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Moore <pmoore@redhat.com>,
	Pavel Emelyanov <xemul@parallels.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Richard Weinberger <richard@nod.at>,
	Sasha Levin <sasha.levin@oracle.com>,
	Shuah Khan <shuahkh@osg.samsung.com>, Tejun Heo <tj@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vladimir Davydov <vdavydov@parallels.com>,
	linux-api@vger.kernel.org
Subject: Re: [PATCH 1/4] signals/sigaltstack: If SS_AUTODISARM, bypass on_sig_stack
Date: Wed, 4 May 2016 08:32:33 +0200	[thread overview]
Message-ID: <20160504063233.GB9499@gmail.com> (raw)
In-Reply-To: <c46bee4654ca9e68c498462fd11746e2bd0d98c8.1462296606.git.luto@kernel.org>


* Andy Lutomirski <luto@kernel.org> wrote:

> If a signal stack is set up with SS_AUTODISARM, then the kernel
> inherently avoids incorrectly resetting the signal stack if signals
> recurse: the signal stack will be reset on the first signal
> delivery.  This means that we don't need check the stack pointer
> when delivering signals if SS_AUTODISARM is set.
> 
> This will make segmented x86 programs more robust: currently there's
> a hole that could be triggered if ESP/RSP appears to point to the
> signal stack but actually doesn't due to a nonzero SS base.
> 
> Signed-off-by: Stas Sergeev <stsp@list.ru>

Presuably that SOB from Stas is stray, as there's no matching From: line?
I've removed it.

Thanks,

	Ingo

  parent reply	other threads:[~2016-05-04  6:32 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-03 17:31 [PATCH 0/4] SS_AUTODISARM fixes and an ABI change Andy Lutomirski
2016-05-03 17:31 ` [PATCH 1/4] signals/sigaltstack: If SS_AUTODISARM, bypass on_sig_stack Andy Lutomirski
2016-05-03 17:31   ` Andy Lutomirski
2016-05-04  7:12   ` [tip:core/signals] signals/sigaltstack: If SS_AUTODISARM, bypass on_sig_stack() tip-bot for Andy Lutomirski
     [not found]   ` <c46bee4654ca9e68c498462fd11746e2bd0d98c8.1462296606.git.luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2016-05-04  6:32     ` Ingo Molnar [this message]
2016-05-04  6:32       ` [PATCH 1/4] signals/sigaltstack: If SS_AUTODISARM, bypass on_sig_stack Ingo Molnar
     [not found]       ` <20160504063233.GB9499-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
2016-05-04 23:02         ` Andy Lutomirski
2016-05-04 23:02           ` Andy Lutomirski
2016-05-07 14:37     ` Stas Sergeev
2016-05-07 14:37       ` Stas Sergeev
2016-05-09  1:32       ` Andy Lutomirski
2016-05-09  1:32         ` Andy Lutomirski
     [not found]         ` <CALCETrX4AMCUkYMXe6-RoHTHQ=bpunM5keHSxMg=fEVtb1EmqA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-05-09  2:04           ` Stas Sergeev
2016-05-09  2:04             ` Stas Sergeev
     [not found]             ` <97f8e27a-019c-a5d4-2d2c-c2a9627cf23d-cmBhpYW9OiY@public.gmane.org>
2016-05-14  4:18               ` Andy Lutomirski
2016-05-14  4:18                 ` Andy Lutomirski
     [not found]                 ` <CALCETrV+gmXn-kTJmKBDPM8HaRTcvp+eGmeF7mOES6bCje2AGQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-05-14 11:18                   ` Stas Sergeev
2016-05-14 11:18                     ` Stas Sergeev
2016-05-14 16:35                     ` Andy Lutomirski
2016-05-14 16:35                       ` Andy Lutomirski
2016-05-03 17:31 ` [PATCH 2/4] selftests/sigaltstack: Fix the sas test on old kernels Andy Lutomirski
2016-05-04  7:13   ` [tip:core/signals] selftests/sigaltstack: Fix the sigaltstack " tip-bot for Andy Lutomirski
     [not found]   ` <f3e739bf435beeaecbd5f038f1359d2eac6d1e63.1462296606.git.luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2016-05-07 15:02     ` [PATCH 2/4] selftests/sigaltstack: Fix the sas " Stas Sergeev
2016-05-07 15:02       ` Stas Sergeev
     [not found]       ` <abedee05-5671-7ba7-c256-41e61fb596cb-cmBhpYW9OiY@public.gmane.org>
2016-05-09  1:32         ` Andy Lutomirski
2016-05-09  1:32           ` Andy Lutomirski
2016-05-03 17:31 ` [PATCH 3/4] signals/sigaltstack: Report current flag bits in sigaltstack() Andy Lutomirski
     [not found]   ` <94b291ec9fd47741a9264851e316e158ded0b00d.1462296606.git.luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2016-05-04  6:33     ` Ingo Molnar
2016-05-04  6:33       ` Ingo Molnar
2016-05-04  7:13   ` [tip:core/signals] " tip-bot for Andy Lutomirski
2016-05-03 17:31 ` [PATCH 4/4] signals/sigaltstack: Change SS_AUTODISARM to (1U << 31) Andy Lutomirski
2016-05-03 17:31   ` Andy Lutomirski
2016-05-04  7:13   ` [tip:core/signals] " tip-bot for Andy Lutomirski
     [not found]   ` <bb996508a600af14b406810c3d58fe0e0d0afe0d.1462296606.git.luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2016-05-07 15:16     ` [PATCH 4/4] " Stas Sergeev
2016-05-07 15:16       ` Stas Sergeev
2016-05-04  6:25 ` [PATCH 0/4] SS_AUTODISARM fixes and an ABI change Ingo Molnar

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