(old discussion, changing title) Johan Hovold <johan@xxxxxxxxxx> writes: > On Tue, Oct 24, 2023 at 05:07:38PM +0300, Kalle Valo wrote: > >> Johan Hovold <johan+linaro@xxxxxxxxxx> writes: >> >> > RCU lockdep reported suspicious RCU usage when accessing the temperature >> > sensor. Inspection revealed that the DFS radar event code was also >> > missing the required RCU read-side critical section marking. >> > >> > Johan >> > >> > >> > Changes in v2 >> > - add the missing rcu_read_unlock() to an >> > ath11k_wmi_pdev_temperature_event() error path as noticed by Jeff >> > >> > >> > Johan Hovold (2): >> > wifi: ath11k: fix temperature event locking >> > wifi: ath11k: fix dfs radar event locking >> >> Thanks for the fixes. I really like using lockdep_assert_held() to >> document if a function requires some lock held, is there anything >> similar for RCU? > > Not really, but the checking is instead built into the primitives like > rcu_dereference() and enabled whenever CONFIG_PROVE_RCU is set. > > For some special cases, we have open-coded checks like: > > RCU_LOCKDEP_WARN(!rcu_read_lock_held()); > > which similarly depend on CONFIG_PROVE_RCU or simply > > WARN_ON_ONCE(!rcu_read_lock_held()); I just found out that sparse has __must_hold(): https://lore.kernel.org/linux-wireless/87sf31hhfp.fsf@xxxxxxxxxx/ That looks promising, should we start using that in ath11k and ath12k to check our RCU usage? -- https://patchwork.kernel.org/project/linux-wireless/list/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches
