Marc Kleine-Budde mkl@pengutronix.de :
The dm9000 takes the db->lock spin lock in dm9000_timeout() and calls into dm9000_init_dm9000(). For the DM9000B the PHY is reset with dm9000_phy_write(). That function again takes the db->lock spin lock, which results in a deadlock. For reference the backtrace:
[...]
To workaround similar problem (take mutex inside spin lock ) , a "in_timeout" variable was added in 582379839bbd ("dm9000: avoid sleeping in dm9000_timeout callback"). Use this variable and not take the spin lock inside dm9000_phy_write() if in_timeout is true.
Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de
During the netdev watchdog handling the dm9000 driver takes the same spin lock twice. Avoid this by extending an existing workaround.
I can review it but I can't really endorse it. :o)
Extending ugly workaround in pre-2000 style device drivers... I'd rather see the thing fixed if there is some real use for it.