On Tue, May 09, 2023 at 08:06:32AM +0200, Louis Peens wrote:
> From: Tianyu Yuan <tianyu.yuan@xxxxxxxxxxxx>
>
> When CONFIG_PROVE_LOCKING and CONFIG_PROVE_RCU are enabled, using
> OVS with vf reprs on bridge will lead to following log in dmesg:
>
> '''
> .../nfp/flower/main.c:269 suspicious rcu_dereference_check() usage!
>
> other info that might help us debug this:
>
> rcu_scheduler_active = 2, debug_locks = 1
> no locks held by swapper/15/0.
>
> ......
> Call Trace:
> <IRQ>
> dump_stack_lvl+0x8c/0xa0
> lockdep_rcu_suspicious+0x118/0x1a0
> nfp_flower_dev_get+0xc1/0x240 [nfp]
> nfp_nfd3_rx+0x419/0xb90 [nfp]
> ? validate_chain+0x640/0x1880
> nfp_nfd3_poll+0x3e/0x180 [nfp]
> __napi_poll+0x28/0x1d0
> net_rx_action+0x2bd/0x3c0
> ? _raw_spin_unlock_irqrestore+0x42/0x70
> __do_softirq+0xc3/0x3c6
> irq_exit_rcu+0xeb/0x130
> common_interrupt+0xb9/0xd0
> </IRQ>
> <TASK>
> ......
> </TASK>
> '''
>
> This debug log is caused by missing of rcu_read_lock()/unlock().
> In previous patch rcu_read_lock/unlock are removed while they are
> still needed when calling rcu_dereference() in nfp_app_dev_get().
>
> Fixes: d5789621b658 ("nfp: Remove rcu_read_lock() around XDP program invocation")
> CC: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Tianyu Yuan <tianyu.yuan@xxxxxxxxxxxx>
> Acked-by: Simon Horman <simon.horman@xxxxxxxxxxxx>
> Signed-off-by: Louis Peens <louis.peens@xxxxxxxxxxxx>
> ---
> drivers/net/ethernet/netronome/nfp/nfd3/dp.c | 4 ++--
> drivers/net/ethernet/netronome/nfp/nfd3/xsk.c | 2 +-
> drivers/net/ethernet/netronome/nfp/nfdk/dp.c | 4 ++--
> drivers/net/ethernet/netronome/nfp/nfp_app.h | 16 ++++++++++++++++
> 4 files changed, 21 insertions(+), 5 deletions(-)
>
Thanks,
Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxx>
