From: Guenter Roeck <linux@roeck-us.net>
To: Doug Anderson <dianders@chromium.org>, wim@iguana.be
Cc: jszhang@marvell.com, linux-watchdog@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] watchdog: dw_wdt: Use a mutex, not a spinlock
Date: Thu, 07 May 2015 18:47:17 -0700 [thread overview]
Message-ID: <554C15A5.2040300@roeck-us.net> (raw)
In-Reply-To: <1431036564-4189-1-git-send-email-dianders@chromium.org>
On 05/07/2015 03:09 PM, Doug Anderson wrote:
> Right now the dw_wdt uses a spinlock to protect dw_wdt_open(). The
> problem is that while holding the spinlock we call:
> -> dw_wdt_set_top()
> -> dw_wdt_top_in_seconds()
> -> clk_get_rate()
> -> clk_prepare_lock()
> -> mutex_lock()
>
> Locking a mutex while holding a spinlock is not allowed and leads to
> warnings like "BUG: spinlock wrong CPU on CPU#1", among other
> problems.
>
> There's no reason to use a spinlock, so switch to a mutex.
>
> Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
next prev parent reply other threads:[~2015-05-08 1:47 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-07 22:09 [PATCH 1/2] watchdog: dw_wdt: Use a mutex, not a spinlock Doug Anderson
2015-05-07 22:09 ` [PATCH 2/2] watchdog: dw_wdt: keepalive the watchdog at write time Doug Anderson
2015-05-08 1:47 ` Guenter Roeck
2015-05-08 2:41 ` Jisheng Zhang
2015-05-08 1:47 ` Guenter Roeck [this message]
2015-05-08 4:01 ` [PATCH 1/2] watchdog: dw_wdt: Use a mutex, not a spinlock Doug Anderson
2015-05-08 2:40 ` Jisheng Zhang
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