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From: Andy Lutomirski <luto@amacapital.net>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Mathias Krause <minipli@googlemail.com>,
	stable <stable@vger.kernel.org>
Subject: Re: [patch 2/3] x86/vdso: Plug race between mapping and ELF header setup
Date: Mon, 10 Apr 2017 08:56:06 -0700	[thread overview]
Message-ID: <CALCETrWfdOn0nyYYghmDydu1ZcfV0ZFgwp3VCV4HtHJHJBP3pg@mail.gmail.com> (raw)
In-Reply-To: <20170410151723.602367196@linutronix.de>

On Mon, Apr 10, 2017 at 8:14 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> The vsyscall32 sysctl can racy against a concurrent fork when it switches
> from disabled to enabled:
>
>     arch_setup_additional_pages()
>         if (vdso32_enabled)
>            --> No mapping
>                                         sysctl.vsysscall32()
>                                           --> vdso32_enabled = true
>     create_elf_tables()
>       ARCH_DLINFO_IA32
>         if (vdso32_enabled) {
>            --> Add VDSO entry with NULL pointer
>
> Make ARCH_DLINFO_IA32 check whether the VDSO mapping has been set up for
> the newly forked process or not.

Acked-by: Andy Lutomirski <luto@kernel.org>

  reply	other threads:[~2017-04-10 15:56 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-10 15:14 [patch 0/3] x86/vdso: Fix enable inconsistencies and cleanup Thomas Gleixner
2017-04-10 15:14 ` [patch 1/3] x86/vdso: Ensure vdso32_enabled gets set to valid values only Thomas Gleixner
2017-04-10 16:34   ` [tip:x86/urgent] " tip-bot for Mathias Krause
2017-04-10 15:14 ` [patch 2/3] x86/vdso: Plug race between mapping and ELF header setup Thomas Gleixner
2017-04-10 15:56   ` Andy Lutomirski [this message]
2017-04-10 16:34   ` [tip:x86/urgent] " tip-bot for Thomas Gleixner
2017-04-10 15:14 ` [patch 3/3] x86/vdso: Sanitize vdso*_enabled handling Thomas Gleixner
2017-04-10 15:55   ` Andy Lutomirski
2017-04-10 16:25     ` Thomas Gleixner
  -- strict thread matches above, loose matches on Subject: below --
2017-04-05 20:36 [PATCH] x86/vdso: ensure vdso32_enabled gets set to valid values only Mathias Krause
2017-04-06 15:59 ` Andy Lutomirski
2017-04-10 13:13 ` Thomas Gleixner
2017-04-10 13:41   ` Thomas Gleixner

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