wifi: wilc1000: unregister wiphy only if it has been registered

There is a specific error path in probe functions in wilc drivers (both
sdio and spi) which can lead to kernel panic, as this one for example
when using SPI:

Unable to handle kernel paging request at virtual address 9f000000 when read
[9f000000] *pgd=00000000
Internal error: Oops: 5 [#1] ARM
Modules linked in: wilc1000_spi(+) crc_itu_t crc7 wilc1000 cfg80211 bluetooth ecdh_generic ecc
CPU: 0 UID: 0 PID: 106 Comm: modprobe Not tainted 6.13.0-rc3+ #22
Hardware name: Atmel SAMA5
PC is at wiphy_unregister+0x244/0xc40 [cfg80211]
LR is at wiphy_unregister+0x1c0/0xc40 [cfg80211]
[...]
 wiphy_unregister [cfg80211] from wilc_netdev_cleanup+0x380/0x494 [wilc1000]
 wilc_netdev_cleanup [wilc1000] from wilc_bus_probe+0x360/0x834 [wilc1000_spi]
 wilc_bus_probe [wilc1000_spi] from spi_probe+0x15c/0x1d4
 spi_probe from really_probe+0x270/0xb2c
 really_probe from __driver_probe_device+0x1dc/0x4e8
 __driver_probe_device from driver_probe_device+0x5c/0x140
 driver_probe_device from __driver_attach+0x220/0x540
 __driver_attach from bus_for_each_dev+0x13c/0x1a8
 bus_for_each_dev from bus_add_driver+0x2a0/0x6a4
 bus_add_driver from driver_register+0x27c/0x51c
 driver_register from do_one_initcall+0xf8/0x564
 do_one_initcall from do_init_module+0x2e4/0x82c
 do_init_module from load_module+0x59a0/0x70c4
 load_module from init_module_from_file+0x100/0x148
 init_module_from_file from sys_finit_module+0x2fc/0x924
 sys_finit_module from ret_fast_syscall+0x0/0x1c

The issue can easily be reproduced, for example by not wiring correctly
a wilc device through SPI (and so, make it unresponsive to early SPI
commands). It is due to a recent change decoupling wiphy allocation from
wiphy registration, however wilc_netdev_cleanup has not been updated
accordingly, letting it possibly call wiphy unregister on a wiphy which
has never been registered.

Fix this crash by moving wiphy_unregister/wiphy_free out of
wilc_netdev_cleanup, and by adjusting error paths in both drivers

Fixes: fbdf0c5248dc ("wifi: wilc1000: Register wiphy after reading out chipid")
Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://patch.msgid.link/20241223-wilc_fix_probe_error_path-v1-1-91fa7bd8e5b6@bootlin.com

1 files changed, 7 insertions, 2 deletions

diff --git a/drivers/net/wireless/microchip/wilc1000/spi.c b/drivers/net/wireless/microchip/wilc1000/spi.c
index ce2a9cdd6aa7..31219fd0cfb3 100644
--- a/drivers/net/wireless/microchip/wilc1000/spi.c
+++ b/drivers/net/wireless/microchip/wilc1000/spi.c
@@ -256,7 +256,7 @@ static int wilc_bus_probe(struct spi_device *spi)
 	ret = wilc_load_mac_from_nv(wilc);
 	if (ret) {
 		pr_err("Can not retrieve MAC address from chip\n");
-		goto power_down;
+		goto unregister_wiphy;
 	}
 
 	wilc_wlan_power(wilc, false);
@@ -264,14 +264,17 @@ static int wilc_bus_probe(struct spi_device *spi)
 				   NL80211_IFTYPE_STATION, false);
 	if (IS_ERR(vif)) {
 		ret = PTR_ERR(vif);
-		goto power_down;
+		goto unregister_wiphy;
 	}
 	return 0;
 
+unregister_wiphy:
+	wiphy_unregister(wilc->wiphy);
 power_down:
 	wilc_wlan_power(wilc, false);
 netdev_cleanup:
 	wilc_netdev_cleanup(wilc);
+	wiphy_free(wilc->wiphy);
 free:
 	kfree(spi_priv);
 	return ret;
@@ -282,7 +285,9 @@ static void wilc_bus_remove(struct spi_device *spi)
 	struct wilc *wilc = spi_get_drvdata(spi);
 	struct wilc_spi *spi_priv = wilc->bus_data;
 
+	wiphy_unregister(wilc->wiphy);
 	wilc_netdev_cleanup(wilc);
+	wiphy_free(wilc->wiphy);
 	kfree(spi_priv);
 }