From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2] arm: Fix backtrace generation when IPI is masked
Date: Tue, 15 Sep 2015 12:30:03 +0100 [thread overview]
Message-ID: <20150915113003.GS21084@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1442315112-14039-1-git-send-email-daniel.thompson@linaro.org>
On Tue, Sep 15, 2015 at 12:05:12PM +0100, Daniel Thompson wrote:
> Currently on ARM when <SysRq-L> is triggered from an interrupt handler
> (e.g. a SysRq issued using UART or kbd) the main CPU will wedge for ten
> seconds with interrupts masked before issuing a backtrace for every CPU
> except itself.
>
> The new backtrace code introduced by commit 96f0e00378d4 ("ARM: add
> basic support for on-demand backtrace of other CPUs") does not work
> correctly when run from an interrupt handler because IPI_CPU_BACKTRACE
> is used to generate the backtrace on all CPUs but cannot preempt the
> current calling context.
This patch needs a little more work - what happens to the IPI_CPU_BACKTRACE
we've sent to ourselves? (It fires after the interrupt handler for the
UART/kbd has finished.) It ought to be masked out if we're going to
handle it a different way.
--
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
WARNING: multiple messages have this Message-ID (diff)
From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: Daniel Thompson <daniel.thompson@linaro.org>
Cc: linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, patches@linaro.org,
linaro-kernel@lists.linaro.org,
Thomas Gleixner <tglx@linutronix.de>,
Hillf Danton <hillf.zj@alibaba-inc.com>
Subject: Re: [PATCH v2] arm: Fix backtrace generation when IPI is masked
Date: Tue, 15 Sep 2015 12:30:03 +0100 [thread overview]
Message-ID: <20150915113003.GS21084@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <1442315112-14039-1-git-send-email-daniel.thompson@linaro.org>
On Tue, Sep 15, 2015 at 12:05:12PM +0100, Daniel Thompson wrote:
> Currently on ARM when <SysRq-L> is triggered from an interrupt handler
> (e.g. a SysRq issued using UART or kbd) the main CPU will wedge for ten
> seconds with interrupts masked before issuing a backtrace for every CPU
> except itself.
>
> The new backtrace code introduced by commit 96f0e00378d4 ("ARM: add
> basic support for on-demand backtrace of other CPUs") does not work
> correctly when run from an interrupt handler because IPI_CPU_BACKTRACE
> is used to generate the backtrace on all CPUs but cannot preempt the
> current calling context.
This patch needs a little more work - what happens to the IPI_CPU_BACKTRACE
we've sent to ourselves? (It fires after the interrupt handler for the
UART/kbd has finished.) It ought to be masked out if we're going to
handle it a different way.
--
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2015-09-15 11:30 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-14 9:18 [PATCH] arm: Fix backtrace generation when IPI is masked Daniel Thompson
2015-09-14 9:18 ` Daniel Thompson
2015-09-15 11:05 ` [PATCH v2] " Daniel Thompson
2015-09-15 11:05 ` Daniel Thompson
2015-09-15 11:30 ` Russell King - ARM Linux [this message]
2015-09-15 11:30 ` Russell King - ARM Linux
2015-09-15 13:15 ` Daniel Thompson
2015-09-15 13:15 ` Daniel Thompson
2015-09-15 13:42 ` Russell King - ARM Linux
2015-09-15 13:42 ` Russell King - ARM Linux
2015-09-15 14:40 ` [PATCH v3] " Daniel Thompson
2015-09-15 14:40 ` Daniel Thompson
2015-09-16 2:43 ` Hillf Danton
2015-09-16 2:43 ` Hillf Danton
2015-09-22 10:59 ` Thomas Gleixner
2015-09-22 10:59 ` Thomas Gleixner
2015-10-03 15:40 ` Russell King - ARM Linux
2015-10-03 15:40 ` Russell King - ARM Linux
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