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From: u3557@miso.sublimeip.com (Amnon Shiloh)
To: gorcunov@openvz.org (Cyrill Gorcunov)
Cc: avagin@gmail.com (Andrey Wagin), oleg@redhat.com (Oleg Nesterov),
	xemul@parallels.com (Pavel Emelyanov),
	rostedt@goodmis.org (Steven Rostedt),
	fweisbec@gmail.com (Frederic Weisbecker),
	mingo@redhat.com (Ingo Molnar),
	a.p.zijlstra@chello.nl (Peter Zijlstra),
	linux-kernel@vger.kernel.org (LKML)
Subject: Re: vdso && cr (Was: arch_check_bp_in_kernelspace: fix the range
Date: Tue, 27 Nov 2012 01:26:55 +1100 (EST)	[thread overview]
Message-ID: <20121126142655.9AD28592064@miso.sublimeip.com> (raw)
In-Reply-To: <20121126141843.GE10312@moon>

Hi Cyrill,

Programmers don't (and the manual-page says they shouldn't even try)
call "sigreturn" directly.

If an interrupt happens, by bad luck, to occur while the process
is running vdso code, then eventually, once signal-processing is
complete, "sigreturn" (issued by  glibc) will take the process back
to where it was before the interrupt happend, inside the vdso page.

Best Regards,
Amnon.

> On Mon, Nov 26, 2012 at 11:55:01PM +1100, Amnon Shiloh wrote:
> > 
> > You could of course keep that old code and modify only the very
> > first instruction of each routine into a jump instruction, but then
> > the code to which the process returns may not be compatible with
> > the new kernel and/or hardware configuration.
> 
> For sure there will be some limitations but I fear we can't do
> that much with it. I don't expect the regular program to use
> sigreturn for jumping into vdso code, but I could be wrong.
> 
> 	Cyrill
> 


  reply	other threads:[~2012-11-26 14:26 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-09 18:29 [PATCH] arch_check_bp_in_kernelspace: fix the range check Oleg Nesterov
2012-11-09 18:30 ` Oleg Nesterov
2012-11-19 17:47   ` Oleg Nesterov
2012-11-19 18:25     ` Steven Rostedt
2012-11-20 10:33       ` u3557
2012-11-20 15:48       ` Oleg Nesterov
2012-11-20 15:55         ` Steven Rostedt
2012-11-20 18:32         ` Oleg Nesterov
2012-11-20 23:16           ` u3557
2012-11-21 14:16             ` Oleg Nesterov
2012-11-21 17:30               ` Amnon Shiloh
2012-11-22 16:12                 ` vdso && cr (Was: arch_check_bp_in_kernelspace: fix the range check) Oleg Nesterov
2012-11-22 20:57                   ` Pavel Emelyanov
2012-11-23  0:20                     ` vdso && cr (Was: arch_check_bp_in_kernelspace: fix the range Amnon Shiloh
2012-11-23 17:45                       ` Oleg Nesterov
2012-11-24 12:47                         ` Amnon Shiloh
2012-11-23 17:42                     ` vdso && cr (Was: arch_check_bp_in_kernelspace: fix the range check) Oleg Nesterov
2012-11-23  9:14                   ` arch_check_bp_in_kernelspace: fix the range check Amnon Shiloh
2012-11-23 16:33                     ` Oleg Nesterov
2012-11-23 17:05                       ` Oleg Nesterov
2012-11-24 14:14                         ` Amnon Shiloh
2012-11-24 13:45                       ` Amnon Shiloh
2012-11-25 22:55                         ` Oleg Nesterov
2012-11-25 23:48                           ` Amnon Shiloh
2012-12-02 19:30                             ` PTRACE_SYSCALL && vsyscall (Was: arch_check_bp_in_kernelspace: fix the range check) Oleg Nesterov
2012-12-02 23:54                               ` u3557
2012-12-04 17:59                                 ` Oleg Nesterov
2012-12-04 22:44                                   ` u3557
2013-01-08 17:08                                   ` Pedro Alves
2013-01-09 17:52                                     ` Oleg Nesterov
2013-01-10  6:54                                       ` u3557
2013-01-12 18:12                                         ` Oleg Nesterov
2013-01-14  2:31                                           ` u3557
2013-01-14 16:01                                             ` Oleg Nesterov
2013-02-18  1:39                                               ` prctl(PR_SET_MM) Amnon Shiloh
2013-02-18  5:44                                                 ` prctl(PR_SET_MM) Randy Dunlap
2013-02-18 15:21                                                 ` prctl(PR_SET_MM) Steven Rostedt
2013-02-18 16:33                                                   ` prctl(PR_SET_MM) Amnon Shiloh
2013-02-18 19:49                                                     ` prctl(PR_SET_MM) Steven Rostedt
2013-02-19  6:25                                                       ` prctl(PR_SET_MM) Amnon Shiloh
2013-02-20  8:39                                                         ` prctl(PR_SET_MM) Cyrill Gorcunov
2013-02-20  9:38                                                           ` prctl(PR_SET_MM) Amnon Shiloh
2013-02-20 10:51                                                             ` prctl(PR_SET_MM) Cyrill Gorcunov
2013-02-20 11:16                                                               ` prctl(PR_SET_MM) Amnon Shiloh
2013-02-21  7:46                                                               ` prctl(PR_SET_MM) Amnon Shiloh
2013-02-21  8:00                                                                 ` prctl(PR_SET_MM) Cyrill Gorcunov
2013-02-21  8:03                                                                   ` prctl(PR_SET_MM) Amnon Shiloh
2013-02-21  8:09                                                                     ` prctl(PR_SET_MM) Cyrill Gorcunov
2013-02-21 22:18                                                                   ` prctl(PR_SET_MM) Andrew Morton
2013-02-21 22:42                                                                     ` prctl(PR_SET_MM) Cyrill Gorcunov
2013-02-22  1:18                                                                     ` prctl(PR_SET_MM) Amnon Shiloh
2013-02-22 14:23                                                         ` prctl(PR_SET_MM) Denys Vlasenko
2012-12-05  9:29                               ` PTRACE_SYSCALL && vsyscall (Was: arch_check_bp_in_kernelspace: fix the range check) Jan Kratochvil
2012-12-05 13:14                                 ` u3557
2012-11-26  9:44                   ` vdso && cr " Cyrill Gorcunov
2012-11-26 12:27                     ` Andrey Wagin
2012-11-26 12:55                       ` Amnon Shiloh
2012-11-26 14:18                         ` Cyrill Gorcunov
2012-11-26 14:26                           ` Amnon Shiloh [this message]
2012-11-26 14:41                             ` vdso && cr Cyrill Gorcunov

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