From: Paul Gortmaker <paul.gortmaker@windriver.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
x86@kernel.org, regressions@leemhuis.info,
richard.purdie@linuxfoundation.org, regressions@lists.linux.dev
Subject: Re: [patch 0/2] x86/alternatives: Prevent crash in NOP optimizer
Date: Fri, 8 Dec 2023 03:35:01 -0500 [thread overview]
Message-ID: <ZXLVNeWBOWiauOjT@windriver.com> (raw)
In-Reply-To: <20231207193859.961361261@linutronix.de>
[[patch 0/2] x86/alternatives: Prevent crash in NOP optimizer] On 07/12/2023 (Thu 20:49) Thomas Gleixner wrote:
> 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.
I can confirm that - since I was already set up for it, I let it run
overnight for about 1250 attempts. With an average of one in 200 that I
was seeing before, I should have had around six fails. Didn't see one.
> Thanks to Paul for providing all the information!
On behalf of Richard and myself, thanks for the complex fix.
Paul.
--
>
> Thanks,
>
> tglx
>
>
next prev parent reply other threads:[~2023-12-08 8:35 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-29 18:41 32 bit qemu regression from v6.5 tip pull [6c480f222128 x86/alternative: Rewrite optimize_nops() some] Paul Gortmaker
2023-10-30 8:26 ` Peter Zijlstra
2023-10-30 10:55 ` Richard Purdie
2023-10-30 11:44 ` Peter Zijlstra
2023-10-30 15:28 ` Paul Gortmaker
2023-10-30 18:24 ` Thomas Gleixner
2023-10-30 19:30 ` Thomas Gleixner
2023-10-31 15:40 ` Paul Gortmaker
2023-11-11 11:51 ` Linux regression tracking (Thorsten Leemhuis)
2023-11-22 14:11 ` Richard Purdie
2023-11-29 8:57 ` Thomas Gleixner
2023-12-06 15:46 ` Paul Gortmaker
2023-12-07 16:34 ` Thomas Gleixner
2023-12-07 16:52 ` Paul Gortmaker
2023-12-07 19:49 ` [patch 0/2] x86/alternatives: Prevent crash in NOP optimizer Thomas Gleixner
2023-12-07 19:49 ` [patch 1/2] x86/alternatives: Sync core before enabling interrupts Thomas Gleixner
2023-12-07 19:49 ` [patch 2/2] x86/alternatives: Disable interrupts and sync when optimizing NOPs in place Thomas Gleixner
2023-12-08 13:22 ` Borislav Petkov
2023-12-08 13:37 ` Thomas Gleixner
2023-12-08 8:35 ` Paul Gortmaker [this message]
2023-12-15 9:10 ` [patch 0/2] x86/alternatives: Prevent crash in NOP optimizer Peter Zijlstra
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