https://github.com/torvalds/linux
Revision 379169740b0a955972cebb4994b2607b264a4b41 authored by Maxim Mikityanskiy on 04 April 2022, 18:51:15 UTC, committed by Saeed Mahameed on 18 May 2022, 06:03:54 UTC
The body of mlx5e_napi_poll is wrapped into rcu_read_lock to be able to
read the XDP program pointer using rcu_dereference. However, the trap RQ
NAPI doesn't use rcu_read_lock, because the trap RQ works only in the
non-linear mode, and mlx5e_skb_from_cqe_nonlinear, until recently,
didn't support XDP and didn't call rcu_dereference.

Starting from the cited commit, mlx5e_skb_from_cqe_nonlinear supports
XDP and calls rcu_dereference, but mlx5e_trap_napi_poll doesn't wrap it
into rcu_read_lock. It leads to RCU-lockdep warnings like this:

    WARNING: suspicious RCU usage

This commit fixes the issue by adding an rcu_read_lock to
mlx5e_trap_napi_poll, similarly to mlx5e_napi_poll.

Fixes: ea5d49bdae8b ("net/mlx5e: Add XDP multi buffer support to the non-linear legacy RQ")
Signed-off-by: Maxim Mikityanskiy <maximmi@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
1 parent 785d7ed
History
Tip revision: 379169740b0a955972cebb4994b2607b264a4b41 authored by Maxim Mikityanskiy on 04 April 2022, 18:51:15 UTC
net/mlx5e: Wrap mlx5e_trap_napi_poll into rcu_read_lock
Tip revision: 3791697
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