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From: Linus Torvalds <torvalds@linux-foundation.org>
To: Andrew Lutomirski <luto@mit.edu>
Cc: Ingo Molnar <mingo@elte.hu>,
	richard -rw- weinberger <richard.weinberger@gmail.com>,
	Adrian Bunk <bunk@stusta.de>,
	"H. Peter Anvin" <hpa@linux.intel.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC] fixing the UML failure root cause
Date: Sat, 15 Oct 2011 08:10:43 +1200	[thread overview]
Message-ID: <CA+55aFx3-F1LzVwN_gSqXcsU7uWda41bHyJxGxHNODWURu0T_g@mail.gmail.com> (raw)
In-Reply-To: <CAObL_7ED+qwOgSH+WsLXvZqC83MX1Q-_1NtcgH-cPe9ghLveZg@mail.gmail.com>

On Fri, Oct 14, 2011 at 6:30 PM, Andrew Lutomirski <luto@mit.edu> wrote:
>
> Another idea is to have a flag that asks the fault handlers to call
> force_sig_info for us.  That's just one bit of per-thread state.  Then
> the vsyscall emulation code could check access_ok, force a signal if
> access is not ok, then set the flag and do the syscall.  And maybe
> some processes would want to opt in to that mode anyway -- arguably
> EFAULT is a serious programmer error and should be dealt with more
> harshly than other syscall misuses.

Ok, so I really like that approach. I could easily see some process
saying "I want a SIGSEGV in addition to the EFAULT that I always get".

And yes, it would fix the vsyscall emulation code which could just
save the thread flag, set it, do the accesses, and restore it to the
old valud.

Please make it so,

          Linus

  reply	other threads:[~2011-10-14 20:11 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-03  9:08 [3.1 patch] x86: default to vsyscall=native Adrian Bunk
2011-10-03 13:04 ` Andrew Lutomirski
2011-10-03 17:33   ` Adrian Bunk
2011-10-03 18:06     ` Andrew Lutomirski
2011-10-03 18:41       ` Adrian Bunk
2011-10-05 22:13     ` Andrew Lutomirski
2011-10-05 22:22       ` richard -rw- weinberger
2011-10-05 22:30         ` Adrian Bunk
2011-10-05 22:41           ` richard -rw- weinberger
2011-10-05 22:46           ` Andrew Lutomirski
2011-10-05 23:36             ` Andrew Lutomirski
2011-10-06  3:06               ` Andrew Lutomirski
2011-10-06 12:12                 ` richard -rw- weinberger
2011-10-06 15:37                 ` richard -rw- weinberger
2011-10-06 18:16                   ` Andrew Lutomirski
2011-10-06 18:34                     ` Linus Torvalds
2011-10-07  0:48                       ` Andrew Lutomirski
2011-10-10 11:19                         ` richard -rw- weinberger
2011-10-10 11:48                           ` Ingo Molnar
2011-10-10 15:31                             ` Andrew Lutomirski
2011-10-11  6:22                               ` Ingo Molnar
2011-10-11 17:24                                 ` [RFC] fixing the UML failure root cause Andrew Lutomirski
2011-10-13  6:19                                   ` Linus Torvalds
2011-10-13  8:40                                     ` Andrew Lutomirski
2011-10-14  4:46                                       ` Linus Torvalds
2011-10-14  6:30                                         ` Andrew Lutomirski
2011-10-14 20:10                                           ` Linus Torvalds [this message]
2011-10-21 21:01                                             ` [PATCH] x86-64: Set siginfo and context on vsyscall emulation faults Andy Lutomirski
2011-10-22  4:46                                               ` Linus Torvalds
2011-10-22  9:07                                                 ` Andy Lutomirski
2011-11-08  0:33                                                   ` [PATCH 0/2] Fix and re-enable vsyscall=emulate Andy Lutomirski
2011-11-08  0:33                                                     ` [PATCH 1/2] x86-64: Set siginfo and context on vsyscall emulation faults Andy Lutomirski
2011-12-05 13:23                                                       ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2011-11-08  0:33                                                     ` [PATCH 2/2] x86: Default to vsyscall=emulate Andy Lutomirski
2011-12-05 13:24                                                       ` [tip:x86/asm] " tip-bot for Andy Lutomirski
2011-12-02 22:47                                                     ` [PATCH 0/2] Fix and re-enable vsyscall=emulate Andy Lutomirski
2011-12-05 11:18                                                       ` H. Peter Anvin
2011-10-14 19:53                                   ` [RFC] fixing the UML failure root cause richard -rw- weinberger
2011-10-14 20:17                                     ` Andrew Lutomirski
2011-10-14 20:23                                       ` richard -rw- weinberger
2011-10-14 20:31                                         ` Andrew Lutomirski
2011-10-14 20:39                                           ` richard -rw- weinberger
2011-10-14 22:28                                       ` richard -rw- weinberger
2011-10-15 16:57                                         ` Ingo Molnar
2011-10-05 22:24       ` [3.1 patch] x86: default to vsyscall=native Adrian Bunk
2011-10-03 13:19 ` richard -rw- weinberger
2011-10-03 17:46   ` Adrian Bunk

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