Linux Serial subsystem development
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From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Jun Chen <jun.d.chen@intel.com>
Cc: alan@linux.intel.com, linux-serial@vger.kernel.org,
	russ.gorby@intel.com, chuansheng.liu@intel.com,
	chao.bi@intel.com
Subject: Re: [PATCH] serial: ifx6x60: add_timer is not safe in the mrdy_assert function
Date: Mon, 22 Oct 2012 10:55:31 +0100	[thread overview]
Message-ID: <20121022105531.072a88f7@pyramind.ukuu.org.uk> (raw)
In-Reply-To: <1350915787.4332.27.camel@chenjun-workstation>

On Mon, 22 Oct 2012 10:23:07 -0400
Jun Chen <jun.d.chen@intel.com> wrote:

> 
> This patch make use of mod_timer instead of add_timer in the mrdy_assert function.
> Because the srdy interrupter can go high when we are running function mrdy_assert and mrdy_assert
> can be called by multi-entry. In our medfield platform, spi stress test can encounter this
> error logs triggered by the BUG_ON of add_timer function.This patch had been tested on
> our medfield platform.
> 
> the scenario:
>       CPU0							CPU1
> mrdy_assert
> set_bit(IFX_SPI_STATE_TIMER_PENDING)
> 								ifx_spi_handle_srdy
> 								...
> 								clear_bit(IFX_SPI_STATE_TIMER_PENDING)
> 								...
> 								mrdy_assert
> 								set_bit(IFX_SPI_STATE_TIMER_PENDING)
> 								...
> 								add_timer
> ...
> add_timer
> 
> cc:liu chuansheng <chuansheng.liu@intel.com>
> cc:Bi Chao <chao.bi@intel.com>
> Signed-off-by: Chen Jun <jun.d.chen@intel.com>

Acked-by: Alan Cox <alan@linux.intel.com>

      reply	other threads:[~2012-10-22  9:50 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-22 14:23 [PATCH] serial: ifx6x60: add_timer is not safe in the mrdy_assert function Jun Chen
2012-10-22  9:55 ` Alan Cox [this message]

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