From: Arun Ramadoss arun.ramadoss@microchip.com
stable inclusion from stable-5.10.75 commit f2e1de075018cf71bcd7d628e9f759cb8540b0c3 bugzilla: 182987 https://gitee.com/openeuler/kernel/issues/I4I3MP
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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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 Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com
Signed-off-by: Chen Jun chenjun102@huawei.com --- drivers/net/dsa/microchip/ksz_common.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/net/dsa/microchip/ksz_common.c b/drivers/net/dsa/microchip/ksz_common.c index 88fa0779e0bc..e3c338624b95 100644 --- a/drivers/net/dsa/microchip/ksz_common.c +++ b/drivers/net/dsa/microchip/ksz_common.c @@ -460,8 +460,10 @@ 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);