From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Petr Mladek <pmladek@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>,
Daniel Thompson <daniel.thompson@linaro.org>,
Jiri Kosina <jkosina@suse.com>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
linux-kernel@vger.kernel.org, x86@kernel.org,
linux-arm-kernel@lists.infradead.org,
adi-buildroot-devel@lists.sourceforge.net,
linux-cris-kernel@axis.com, linux-mips@linux-mips.org,
linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
Petr Mladek <pmladek@suse.cz>
Subject: Re: [PATCH v2 3/5] printk/nmi: Try hard to print Oops message in NMI context
Date: Tue, 1 Dec 2015 23:44:37 +0000 [thread overview]
Message-ID: <20151201234437.GA8644@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1448622572-16900-4-git-send-email-pmladek@suse.com>
On Fri, Nov 27, 2015 at 12:09:30PM +0100, Petr Mladek wrote:
> What we can do, though, is to zap all printk locks. We already do this
> when a printk recursion is detected. This should be safe because
> the system is crashing and there shouldn't be any printk caller
> that would cause the deadlock.
What about serial consoles which may call out to subsystems like the
clk subsystem to enable a clock, which would want to take their own
spinlocks in addition to the serial console driver?
I don't see bust_spinlocks() dealing with any of these locks, so IMHO
trying to make this work in NMI context strikes me as making the
existing solution more unreliable on ARM systems.
--
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2015-12-01 23:45 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-27 11:09 [PATCH v2 0/5] Cleaning printk stuff in NMI context Petr Mladek
2015-11-27 11:09 ` [PATCH v2 1/5] printk/nmi: Generic solution for safe printk in NMI Petr Mladek
2015-11-27 11:49 ` kbuild test robot
2015-11-27 15:38 ` Petr Mladek
2015-12-01 23:24 ` Jiri Kosina
2015-12-04 16:57 ` Petr Mladek
2016-03-17 19:35 ` Andrew Morton
2016-03-18 10:03 ` Petr Mladek
2015-11-27 12:02 ` kbuild test robot
2015-11-27 14:26 ` Max Filippov
2015-11-30 14:25 ` Petr Mladek
2015-12-02 2:45 ` Michael Ellerman
2015-12-04 15:29 ` Petr Mladek
2015-11-27 11:09 ` [PATCH v2 2/5] printk/nmi: Use IRQ work only when ready Petr Mladek
2015-11-27 11:09 ` [PATCH v2 3/5] printk/nmi: Try hard to print Oops message in NMI context Petr Mladek
2015-12-01 23:44 ` Russell King - ARM Linux [this message]
2015-12-04 15:27 ` Petr Mladek
2015-12-04 17:12 ` Russell King - ARM Linux
2015-12-07 15:48 ` David Laight
2015-12-08 14:49 ` Petr Mladek
2015-12-08 11:21 ` Petr Mladek
2015-11-27 11:09 ` [PATCH v2 4/5] printk/nmi: Warn when some message has been lost " Petr Mladek
2015-11-27 11:09 ` [PATCH v2 5/5] printk/nmi: Increase the size of the temporary buffer Petr Mladek
2015-11-30 16:42 ` yalin wang
2015-12-02 16:20 ` David Laight
2015-12-04 15:47 ` Petr Mladek
2015-12-07 14:16 ` Petr Mladek
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