watchdog: Fix potential kref imbalance when opening watchdog

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[ Upstream commit 4bcd615fad ]

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().

Fixes: ee142889e3 ("watchdog: Introduce WDOG_HW_RUNNING flag")
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Guenter Roeck 2017-09-25 09:17:01 -07:00 • committed by Greg Kroah-Hartman

parent 008029510a

commit 08b8109010

1 changed files with 4 additions and 2 deletions

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drivers/watchdog/watchdog_dev.c

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