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From:   Thomas Gleixner <tglx@linutronix.de>
To:     LKML <linux-kernel@vger.kernel.org>
Cc:     paul.gortmaker@windriver.com, x86@kernel.org,
        regressions@leemhuis.info, richard.purdie@linuxfoundation.org,
        regressions@lists.linux.dev
References: <ZXCXc+BtnLzqMbFv@windriver.com> <ZUEgAAGDVqXz2Seo@windriver.com>
 <0adb772c-e8d2-4444-92b0-00cbfdaf1fac@leemhuis.info> <87r0k9ym0y.ffs@tglx>
Subject: [patch 0/2] x86/alternatives: Prevent crash in NOP optimizer
Date:   Thu,  7 Dec 2023 20:49:22 +0100 (CET)
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List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

The following series addresses the regression report from Paul on behalf of
the yocto project. It turns out that the recent changes to alternatives
opened a race window where interrupts are enabled and NOPs are optimized in
place. An interrupt hitting into the modification will observe inconsistent
text and crash and burn.

A 32bit QEMU crashes w/o these fixes reliably within about 50 boot
attempts. With the fix applied it survived close to 600 attempts by
now.

Thanks to Paul for providing all the information!

Thanks,

	tglx