[net,v3] net: ftgmac100: Fix crash when removing driver

Message ID 20201117024448.1170761-1-joel@jms.id.au
State New
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Series
  • [net,v3] net: ftgmac100: Fix crash when removing driver
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Commit Message

Joel Stanley Nov. 17, 2020, 2:44 a.m.
When removing the driver we would hit BUG_ON(!list_empty(&dev->ptype_specific))
in net/core/dev.c due to still having the NC-SI packet handler
registered.

 # echo 1e660000.ethernet > /sys/bus/platform/drivers/ftgmac100/unbind
  ------------[ cut here ]------------
  kernel BUG at net/core/dev.c:10254!
  Internal error: Oops - BUG: 0 [#1] SMP ARM
  CPU: 0 PID: 115 Comm: sh Not tainted 5.10.0-rc3-next-20201111-00007-g02e0365710c4 #46
  Hardware name: Generic DT based system
  PC is at netdev_run_todo+0x314/0x394
  LR is at cpumask_next+0x20/0x24
  pc : [<806f5830>]    lr : [<80863cb0>]    psr: 80000153
  sp : 855bbd58  ip : 00000001  fp : 855bbdac
  r10: 80c03d00  r9 : 80c06228  r8 : 81158c54
  r7 : 00000000  r6 : 80c05dec  r5 : 80c05d18  r4 : 813b9280
  r3 : 813b9054  r2 : 8122c470  r1 : 00000002  r0 : 00000002
  Flags: Nzcv  IRQs on  FIQs off  Mode SVC_32  ISA ARM  Segment none
  Control: 00c5387d  Table: 85514008  DAC: 00000051
  Process sh (pid: 115, stack limit = 0x7cb5703d)
 ...
  Backtrace:
  [<806f551c>] (netdev_run_todo) from [<80707eec>] (rtnl_unlock+0x18/0x1c)
   r10:00000051 r9:854ed710 r8:81158c54 r7:80c76bb0 r6:81158c10 r5:8115b410
   r4:813b9000
  [<80707ed4>] (rtnl_unlock) from [<806f5db8>] (unregister_netdev+0x2c/0x30)
  [<806f5d8c>] (unregister_netdev) from [<805a8180>] (ftgmac100_remove+0x20/0xa8)
   r5:8115b410 r4:813b9000
  [<805a8160>] (ftgmac100_remove) from [<805355e4>] (platform_drv_remove+0x34/0x4c)

Fixes: bd466c3fb5a4 ("net/faraday: Support NCSI mode")
Signed-off-by: Joel Stanley <joel@jms.id.au>

---
v3: Apply to net so it can go in as a fix
v2: Also unregister in _probe
---
 drivers/net/ethernet/faraday/ftgmac100.c | 4 ++++
 1 file changed, 4 insertions(+)

-- 
2.29.2

Comments

Jakub Kicinski Nov. 17, 2020, 7 p.m. | #1
On Tue, 17 Nov 2020 13:14:48 +1030 Joel Stanley wrote:
> When removing the driver we would hit BUG_ON(!list_empty(&dev->ptype_specific))

> in net/core/dev.c due to still having the NC-SI packet handler

> registered.

> 

>  # echo 1e660000.ethernet > /sys/bus/platform/drivers/ftgmac100/unbind

>   ------------[ cut here ]------------

>   kernel BUG at net/core/dev.c:10254!

>   Internal error: Oops - BUG: 0 [#1] SMP ARM

>   CPU: 0 PID: 115 Comm: sh Not tainted 5.10.0-rc3-next-20201111-00007-g02e0365710c4 #46

>   Hardware name: Generic DT based system

>   PC is at netdev_run_todo+0x314/0x394

>   LR is at cpumask_next+0x20/0x24

>   pc : [<806f5830>]    lr : [<80863cb0>]    psr: 80000153

>   sp : 855bbd58  ip : 00000001  fp : 855bbdac

>   r10: 80c03d00  r9 : 80c06228  r8 : 81158c54

>   r7 : 00000000  r6 : 80c05dec  r5 : 80c05d18  r4 : 813b9280

>   r3 : 813b9054  r2 : 8122c470  r1 : 00000002  r0 : 00000002

>   Flags: Nzcv  IRQs on  FIQs off  Mode SVC_32  ISA ARM  Segment none

>   Control: 00c5387d  Table: 85514008  DAC: 00000051

>   Process sh (pid: 115, stack limit = 0x7cb5703d)

>  ...

>   Backtrace:

>   [<806f551c>] (netdev_run_todo) from [<80707eec>] (rtnl_unlock+0x18/0x1c)

>    r10:00000051 r9:854ed710 r8:81158c54 r7:80c76bb0 r6:81158c10 r5:8115b410

>    r4:813b9000

>   [<80707ed4>] (rtnl_unlock) from [<806f5db8>] (unregister_netdev+0x2c/0x30)

>   [<806f5d8c>] (unregister_netdev) from [<805a8180>] (ftgmac100_remove+0x20/0xa8)

>    r5:8115b410 r4:813b9000

>   [<805a8160>] (ftgmac100_remove) from [<805355e4>] (platform_drv_remove+0x34/0x4c)

> 

> Fixes: bd466c3fb5a4 ("net/faraday: Support NCSI mode")

> Signed-off-by: Joel Stanley <joel@jms.id.au>


Applied, thanks!

There's at least one more bug here - at least two goto err_ncsi_dev
don't set err, so the function will return 0 even tho there was an
error.

Patch

diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 00024dd41147..80fb1f537bb3 100644
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -1907,6 +1907,8 @@  static int ftgmac100_probe(struct platform_device *pdev)
 	clk_disable_unprepare(priv->rclk);
 	clk_disable_unprepare(priv->clk);
 err_ncsi_dev:
+	if (priv->ndev)
+		ncsi_unregister_dev(priv->ndev);
 	ftgmac100_destroy_mdio(netdev);
 err_setup_mdio:
 	iounmap(priv->base);
@@ -1926,6 +1928,8 @@  static int ftgmac100_remove(struct platform_device *pdev)
 	netdev = platform_get_drvdata(pdev);
 	priv = netdev_priv(netdev);
 
+	if (priv->ndev)
+		ncsi_unregister_dev(priv->ndev);
 	unregister_netdev(netdev);
 
 	clk_disable_unprepare(priv->rclk);