From: Oleksij Rempel <ore@pengutronix.de>
To: Guenter Roeck <linux@roeck-us.net>, Wim Van Sebroeck <wim@iguana.be>
Cc: Oleksij Rempel <o.rempel@pengutronix.de>,
Steffen Trumtrar <s.trumtrar@pengutronix.de>,
linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] watchdog: Fix potential kref imbalance when opening watchdog
Date: Tue, 26 Sep 2017 07:24:10 +0200 [thread overview]
Message-ID: <7f1bad2d-0f82-ee66-e9d2-c67fbe38950a@pengutronix.de> (raw)
In-Reply-To: <1506356222-528-1-git-send-email-linux@roeck-us.net>
On 25.09.2017 18:17, Guenter Roeck wrote:
> If a watchdog driver's open function sets WDOG_HW_RUNNING with the
> expectation that the watchdog can not be stopped, but then stops the
> watchdog anyway in its stop function, kref_get() wil not be called in
> watchdog_open(). If the watchdog then stops on close, WDOG_HW_RUNNING
> will be cleared and kref_put() will be called, causing a kref imbalance.
> As result the character device data structure will be released, which in
> turn will cause the system to crash on the next call to watchdog_open().
Ach, ok. I see. So the stop patch should remove it from the start.
prev parent reply other threads:[~2017-09-26 5:24 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-25 16:17 Guenter Roeck
2017-09-25 16:17 ` [PATCH 2/2] watchdog: Fix kref imbalance seen if handle_boot_enabled=0 Guenter Roeck
2017-09-26 5:24 ` Oleksij Rempel [this message]
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