From: Arun Ramadoss arun.ramadoss@microchip.com
commit ef1100ef20f29aec4e62abeccdb5bdbebba1e378 upstream.
When the ksz module is installed and removed using rmmod, kernel crashes with null pointer dereferrence error. During rmmod, ksz_switch_remove function tries to cancel the mib_read_workqueue using cancel_delayed_work_sync routine and unregister switch from dsa.
During dsa_unregister_switch it calls ksz_mac_link_down, which in turn reschedules the workqueue since mib_interval is non-zero. Due to which queue executed after mib_interval and it tries to access dp->slave. But the slave is unregistered in the ksz_switch_remove function. Hence kernel crashes.
To avoid this crash, before canceling the workqueue, resetted the mib_interval to 0.
v1 -> v2: -Removed the if condition in ksz_mib_read_work
Fixes: 469b390e1ba3 ("net: dsa: microchip: use delayed_work instead of timer + work") Signed-off-by: Arun Ramadoss arun.ramadoss@microchip.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/dsa/microchip/ksz_common.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/net/dsa/microchip/ksz_common.c +++ b/drivers/net/dsa/microchip/ksz_common.c @@ -449,8 +449,10 @@ EXPORT_SYMBOL(ksz_switch_register); void ksz_switch_remove(struct ksz_device *dev) { /* timer started */ - if (dev->mib_read_interval) + if (dev->mib_read_interval) { + dev->mib_read_interval = 0; cancel_delayed_work_sync(&dev->mib_read); + }
dev->dev_ops->exit(dev); dsa_unregister_switch(dev->ds);