From e256f8d845bcf22acad4f81ed04a73dd1f1d05e3 Mon Sep 17 00:00:00 2001 From: Ido Schimmel Date: Thu, 9 Jan 2020 19:57:41 +0200 Subject: [PATCH] devlink: Wait longer before warning about unset port type commit 4c582234ab3948d08a24c82eb1e00436aabacbc6 upstream. The commit cited below causes devlink to emit a warning if a type was not set on a devlink port for longer than 30 seconds to "prevent misbehavior of drivers". This proved to be problematic when unregistering the backing netdev. The flow is always: devlink_port_type_clear() // schedules the warning unregister_netdev() // blocking devlink_port_unregister() // cancels the warning The call to unregister_netdev() can block for long periods of time for various reasons: RTNL lock is contended, large amounts of configuration to unroll following dismantle of the netdev, etc. This results in devlink emitting a warning despite the driver behaving correctly. In emulated environments (of future hardware) which are usually very slow, the warning can also be emitted during port creation as more than 30 seconds can pass between the time the devlink port is registered and when its type is set. In addition, syzbot has hit this warning [1] 1974 times since 07/11/19 without being able to produce a reproducer. Probably because reproduction depends on the load or other bugs (e.g., RTNL not being released). To prevent bogus warnings, increase the timeout to 1 hour. [1] https://syzkaller.appspot.com/bug?id=e99b59e9c024a666c9f7450dc162a4b74d09d9cb Fixes: 136bf27fc0e9 ("devlink: add warning in case driver does not set port type") Signed-off-by: Ido Schimmel Reported-by: syzbot+b0a18ed7b08b735d2f41@syzkaller.appspotmail.com Reported-by: Alex Veber Tested-by: Alex Veber Acked-by: Jiri Pirko Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/core/devlink.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/core/devlink.c b/net/core/devlink.c index 93905dc7c179..ae614965c8c2 100644 --- a/net/core/devlink.c +++ b/net/core/devlink.c @@ -6280,7 +6280,7 @@ static bool devlink_port_type_should_warn(struct devlink_port *devlink_port) devlink_port->attrs.flavour != DEVLINK_PORT_FLAVOUR_DSA; } -#define DEVLINK_PORT_TYPE_WARN_TIMEOUT (HZ * 30) +#define DEVLINK_PORT_TYPE_WARN_TIMEOUT (HZ * 3600) static void devlink_port_type_warn_schedule(struct devlink_port *devlink_port) {