Re: [PATCH net-next 7/7] net: marvell: prestera: fix port event handling on init

Hi Jakub,

On Thu, Feb 04, 2021 at 09:19:34PM -0800, Jakub Kicinski wrote:

On Wed,  3 Feb 2021 18:54:58 +0200 Vadym Kochan wrote:

quoted

For some reason there might be a crash during ports creation if port
events are handling at the same time  because fw may send initial
port event with down state.

The crash points to cancel_delayed_work() which is called when port went
is down.  Currently I did not find out the real cause of the issue, so
fixed it by cancel port stats work only if previous port's state was up
& runnig.

Maybe you just need to move the DELAYED_WORK_INIT() earlier?
Not sure why it's at the end of prestera_port_create(), it 
just initializes some fields.

Thanks for suggestion, but it does not help. Will try to find-out the
real root cause but this is the only fix I 'v came up.

quoted

[   28.489791] Call trace:
[   28.492259]  get_work_pool+0x48/0x60
[   28.495874]  cancel_delayed_work+0x38/0xb0
[   28.500011]  prestera_port_handle_event+0x90/0xa0 [prestera]
[   28.505743]  prestera_evt_recv+0x98/0xe0 [prestera]
[   28.510683]  prestera_fw_evt_work_fn+0x180/0x228 [prestera_pci]
[   28.516660]  process_one_work+0x1e8/0x360
[   28.520710]  worker_thread+0x44/0x480
[   28.524412]  kthread+0x154/0x160
[   28.527670]  ret_from_fork+0x10/0x38
[   28.531290] Code: a8c17bfd d50323bf d65f03c0 9278dc21 (f9400020)
[   28.537429] ---[ end trace 5eced933df3a080b ]---

Signed-off-by: Vadym Kochan <redacted>
---
 drivers/net/ethernet/marvell/prestera/prestera_main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/marvell/prestera/prestera_main.c b/drivers/net/ethernet/marvell/prestera/prestera_main.c
index 39465e65d09b..122324dae47d 100644
--- a/drivers/net/ethernet/marvell/prestera/prestera_main.c
+++ b/drivers/net/ethernet/marvell/prestera/prestera_main.c

@@ -433,7 +433,8 @@ static void prestera_port_handle_event(struct prestera_switch *sw,
 			netif_carrier_on(port->dev);
 			if (!delayed_work_pending(caching_dw))
 				queue_delayed_work(prestera_wq, caching_dw, 0);
-		} else {
+		} else if (netif_running(port->dev) &&
+			   netif_carrier_ok(port->dev)) {
 			netif_carrier_off(port->dev);
 			if (delayed_work_pending(caching_dw))
 				cancel_delayed_work(caching_dw);