BUG: commit "ARM: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW on pre-ARMv6 CPUs" breaks armv5 with CONFIG_PREEMPT

Marc Kleine-Budde mkl at pengutronix.de
Wed Jul 17 04:41:19 EDT 2013

On 06/21/2013 03:52 PM, Catalin Marinas wrote:
> On Fri, Jun 21, 2013 at 11:28:48AM +0100, Marc Kleine-Budde wrote:
>> On 06/20/2013 01:47 PM, Marc Kleine-Budde wrote:
>>> From 306d84d5f0645a86e86d539be0546c4ac758d3d4 Mon Sep 17 00:00:00 2001
>>> From: Catalin Marinas <catalin.marinas at arm.com>
>>> Date: Thu, 20 Jun 2013 12:12:55 +0100
>>> Subject: [PATCH] arm: Fix deferred mm switch on VIVT processors
>>> As of commit b9d4d42ad9 (ARM: Remove __ARCH_WANT_INTERRUPTS_ON_CTXSW on
>>> pre-ARMv6 CPUs), the mm switching on VIVT processors is done in the
>>> finish_arch_post_lock_switch() function to avoid whole cache flushing
>>> with interrupts disabled. The need for deferred mm switch is stored as a
>>> thread flag (TIF_SWITCH_MM). However, with preemption enabled, we can
>>> have another thread switch before finish_arch_post_lock_switch(). If the
>>> new thread has the same mm as the previous 'next' thread, the scheduler
>>> will not call switch_mm() and the TIF_SWITCH_MM flag won't be set for
>>> the new thread.
>>> This patch moves the switch pending flag to the mm_context_t structure
>>> since this is specific to the mm rather than thread.
>>> Signed-off-by: Catalin Marinas <catalin.marinas at arm.com>
>>> Reported-by: Marc Kleine-Budde <mkl at pengutronix.de>
>>> [mkl: add check for mm]
>>> Signed-off-by: Marc Kleine-Budde <mkl at pengutronix.de>
>> Works on $CUSTOMERS's hardware.
>> Tested-by: Marc Kleine-Budde <mkl at pengutronix.de>
> Thanks.
>> Catalin, do you take care of the patch? Please add stable on Cc. The fix
>> is needed on kernels >= v3.5.
> I'll send it to Russell, if possible it should go in for 3.10. I already
> added CC stable in my copy (3.5+).

What happend to that patch? I cannot find it in v3.10.x nor in linus/master.


Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
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