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f7ab9e14b2
commit 7dd9c26bd6cf679bcfdef01a8659791aa6487a29 upstream.
The mcp251x_hw_wake() function is called with the mpc_lock mutex held and
disables the interrupt handler so that no interrupts can be processed while
waking the device. If an interrupt has already occurred then waiting for
the interrupt handler to complete will deadlock because it will be trying
to acquire the same mutex.
CPU0 CPU1
---- ----
mcp251x_open()
mutex_lock(&priv->mcp_lock)
request_threaded_irq()
<interrupt>
mcp251x_can_ist()
mutex_lock(&priv->mcp_lock)
mcp251x_hw_wake()
disable_irq() <-- deadlock
Use disable_irq_nosync() instead because the interrupt handler does
everything while holding the mutex so it doesn't matter if it's still
running.
Fixes: 8ce8c0abcb ("can: mcp251x: only reset hardware as required")
Signed-off-by: Simon Arlott <simon@octiron.net>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/4fc08687-1d80-43fe-9f0d-8ef8475e75f6@0882a8b5-c6c3-11e9-b005-00805fc181fe.uuid.home.arpa
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.