Ido Schimmel wrote:
On Sun, Sep 29, 2024 at 02:18:20AM -0400, Willem de Bruijn wrote:
From: Willem de Bruijn willemb@google.com
This reverts commit 504fc6f4f7f681d2a03aa5f68aad549d90eab853.
dev_queue_xmit_nit is expected to be called with BH disabled. __dev_queue_xmit has the following:
/* Disable soft irqs for various locks below. Also * stops preemption for RCU. */ rcu_read_lock_bh();VRF must follow this invariant. The referenced commit removed this protection. Which triggered a lockdep warning:
[...]
Fixes: 504fc6f4f7f6 ("vrf: Remove unnecessary RCU-bh critical section") Link: https://lore.kernel.org/netdev/20240925185216.1990381-1-greearb@candelatech.... Reported-by: Ben Greear greearb@candelatech.com Signed-off-by: Willem de Bruijn willemb@google.com Cc: stable@vger.kernel.org
Reviewed-by: Ido Schimmel idosch@nvidia.com Tested-by: Ido Schimmel idosch@nvidia.com
Thanks Willem!
Thanks for testing immediately and sharing the below context, Ido!
The reason my script from 504fc6f4f7f6 did not trigger the problem is that it was pinging the address inside the VRF, so vrf_finish_direct() was only called from the Rx path.
If you ping the address outside of the VRF:
ping -I vrf1 -i 0.1 -c 10 -q 192.0.2.1
Then vrf_finish_direct() is called from process context and the lockdep warning is triggered. Tested that it does not trigger after applying the revert.