[RFC PATCH net-next 1/5] net: dsa: realtek-smi: fix mdio_free bug on module unload
From: Alvin Šipraga <hidden>
Date: 2021-08-22 19:32:48
Also in:
lkml, netdev
Subsystem:
networking drivers, networking [dsa], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Vladimir Oltean, Linus Torvalds
From: Alvin Šipraga <alsi@bang-olufsen.dk>
realtek-smi-core fails to unregister the slave MII bus on module unload,
raising the following BUG warning:
mdio_bus.c:650: BUG_ON(bus->state != MDIOBUS_UNREGISTERED);
kernel BUG at drivers/net/phy/mdio_bus.c:650!
Internal error: Oops - BUG: 0 [#1] PREEMPT_RT SMP
Call trace:
mdiobus_free+0x4c/0x50
devm_mdiobus_free+0x18/0x20
release_nodes.isra.0+0x1c0/0x2b0
devres_release_all+0x38/0x58
device_release_driver_internal+0x124/0x1e8
driver_detach+0x54/0xe0
bus_remove_driver+0x60/0xd8
driver_unregister+0x34/0x60
platform_driver_unregister+0x18/0x20
realtek_smi_driver_exit+0x14/0x1c [realtek_smi]
Fix this by duly unregistering the slave MII bus with
mdiobus_unregister. We do this in the DSA teardown path, since
registration is performed in the DSA setup path.
Cc: Linus Walleij <redacted>
Fixes: d8652956cf37 ("net: dsa: realtek-smi: Add Realtek SMI driver")
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
---
drivers/net/dsa/realtek-smi-core.c | 6 ++++++
drivers/net/dsa/realtek-smi-core.h | 1 +
drivers/net/dsa/rtl8366rb.c | 8 ++++++++
3 files changed, 15 insertions(+)
diff --git a/drivers/net/dsa/realtek-smi-core.c b/drivers/net/dsa/realtek-smi-core.c
index 8e49d4f85d48..6992b6b31db6 100644
--- a/drivers/net/dsa/realtek-smi-core.c
+++ b/drivers/net/dsa/realtek-smi-core.c@@ -383,6 +383,12 @@ int realtek_smi_setup_mdio(struct realtek_smi *smi) return ret; } +void realtek_smi_teardown_mdio(struct realtek_smi *smi) +{ + if (smi->slave_mii_bus) + mdiobus_unregister(smi->slave_mii_bus); +} + static int realtek_smi_probe(struct platform_device *pdev) { const struct realtek_smi_variant *var;
diff --git a/drivers/net/dsa/realtek-smi-core.h b/drivers/net/dsa/realtek-smi-core.h
index fcf465f7f922..6cfa5f2df7ea 100644
--- a/drivers/net/dsa/realtek-smi-core.h
+++ b/drivers/net/dsa/realtek-smi-core.h@@ -119,6 +119,7 @@ struct realtek_smi_variant { int realtek_smi_write_reg_noack(struct realtek_smi *smi, u32 addr, u32 data); int realtek_smi_setup_mdio(struct realtek_smi *smi); +void realtek_smi_teardown_mdio(struct realtek_smi *smi); /* RTL8366 library helpers */ int rtl8366_mc_is_used(struct realtek_smi *smi, int mc_index, int *used);
diff --git a/drivers/net/dsa/rtl8366rb.c b/drivers/net/dsa/rtl8366rb.c
index a89093bc6c6a..6537fac7aba4 100644
--- a/drivers/net/dsa/rtl8366rb.c
+++ b/drivers/net/dsa/rtl8366rb.c@@ -982,6 +982,13 @@ static int rtl8366rb_setup(struct dsa_switch *ds) return 0; } +static void rtl8366rb_teardown(struct dsa_switch *ds) +{ + struct realtek_smi *smi = ds->priv; + + realtek_smi_teardown_mdio(smi); +} + static enum dsa_tag_protocol rtl8366_get_tag_protocol(struct dsa_switch *ds, int port, enum dsa_tag_protocol mp)
@@ -1505,6 +1512,7 @@ static int rtl8366rb_detect(struct realtek_smi *smi) static const struct dsa_switch_ops rtl8366rb_switch_ops = { .get_tag_protocol = rtl8366_get_tag_protocol, .setup = rtl8366rb_setup, + .teardown = rtl8366rb_teardown, .phylink_mac_link_up = rtl8366rb_mac_link_up, .phylink_mac_link_down = rtl8366rb_mac_link_down, .get_strings = rtl8366_get_strings,
--
2.32.0