From: "Jörn Engel" <joern@purestorage.com>
To: "Huang, Ying" <ying.huang@intel.com>
Cc: Uday Shankar <ushankar@purestorage.com>,
Kees Cook <keescook@chromium.org>,
Tony Luck <tony.luck@intel.com>,
"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Len Brown <lenb@kernel.org>, James Morse <james.morse@arm.com>,
Borislav Petkov <bp@alien8.de>, Len Brown <len.brown@intel.com>,
linux-hardening@vger.kernel.org, linux-acpi@vger.kernel.org,
Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Subject: Re: [PATCH] Revert "ACPI, APEI, use raw spinlock in ERST"
Date: Mon, 21 Aug 2023 20:16:05 -0700 [thread overview]
Message-ID: <ZOQodU1CNMRtjYZ6@cork> (raw)
In-Reply-To: <87y1i3c015.fsf@yhuang6-desk2.ccr.corp.intel.com>
On Tue, Aug 22, 2023 at 09:56:38AM +0800, Huang, Ying wrote:
>
> ERST is mainly used to log the hardware error. While, hardware error
> may be reported via NMI (e.g., ACPI APEI GHES NMI), so we need to call
> ERST functions in NMI handlers. Where normal spinlock cannot be used
> because they will be converted to sleepable rt_mutex in RT kernel.
Non-sleeping spinlocks cannot be used in NMI context either.
raw_spin_lock_irqsave() will prevent regular interrupts, but not NMI.
So taking a spinlock inside an NMI can trigger a deadlock.
Am I missing something here?
Jörn
--
All art is but imitation of nature.
-- Lucius Annaeus Seneca
next prev parent reply other threads:[~2023-08-22 3:16 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-22 1:09 [PATCH] Revert "ACPI, APEI, use raw spinlock in ERST" Uday Shankar
2023-08-22 1:56 ` Huang, Ying
2023-08-22 3:16 ` Jörn Engel [this message]
2023-08-22 23:45 ` Uday Shankar
2023-08-23 2:38 ` Huang, Ying
2023-08-23 2:57 ` Jörn Engel
2023-08-23 21:09 ` Jörn Engel
2023-08-23 2:28 ` Huang, Ying
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