Commit ff3516442768 ("WAN: HDLC: Detach protocol before unregistering
device") moved protocol detach ahead of netdev unregister so detach could
still use its state. However, detach_hdlc_protocol() calls
hdlc_setup_dev(), which clears IFF_UP. unregister_netdevice() then sees an
already-down device and skips ndo_stop, leaving an active HDLC device
running while its driver releases resources.
Close the device under RTNL while its protocol is still attached, then
keep the existing detach-before-unregister order. This runs the hardware
stop callback and the protocol close callback before their state is
released.
Audit all current users: c101, n2, pc300too, pci200syn, wanxl,
ixp4xx_hss, fsl_qmc_hdlc and farsync unregister before releasing the
resources used by their close callbacks. The farsync probe unwind can
disable interrupts and free its RX DMA buffer first, but fst_close() does
not use that buffer or require interrupts; the card is also in FST_RESET,
so fst_closeport() does not access the port hardware.
Fixes: ff3516442768 ("WAN: HDLC: Detach protocol before unregistering device")
Cc: [email protected]
Reported-by: Jakub Kicinski <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Co-developed-by: Ijae Kim <[email protected]>
Signed-off-by: Ijae Kim <[email protected]>
Signed-off-by: Myeonghun Pak <[email protected]>
---
drivers/net/wan/hdlc.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/net/wan/hdlc.c b/drivers/net/wan/hdlc.c
index cbed10b1d862e..a38f90d3006ed 100644
--- a/drivers/net/wan/hdlc.c
+++ b/drivers/net/wan/hdlc.c
@@ -263,6 +263,7 @@ EXPORT_SYMBOL(alloc_hdlcdev);
void unregister_hdlc_device(struct net_device *dev)
{
rtnl_lock();
+ dev_close(dev);
detach_hdlc_protocol(dev);
unregister_netdevice(dev);
rtnl_unlock();
--
2.47.1
