Re: [PATCH 3.19] ath9k: fix race condition in irq processing during hardware reset

[Rico Derrer <rico.derrer@neratec.com>]

> On 2015-01-16 09:00, Rico Derrer wrote:
>> Hi Felix
>> 
>> Felix Fietkau wrote:
>>> diff --git a/drivers/net/wireless/ath/ath9k/main.c
>>> b/drivers/net/wireless/ath/ath9k/main.c
>>> index 9a72640..62b0bf4 100644
>>> --- a/drivers/net/wireless/ath/ath9k/main.c
>>> +++ b/drivers/net/wireless/ath/ath9k/main.c
>>> @@ -285,6 +285,7 @@ static int ath_reset_internal(struct ath_softc *sc, struct
>>> ath9k_channel *hchan)
>>> 
>>> __ath_cancel_work(sc);
>>> 
>>> + disable_irq(sc->irq);
>>> tasklet_disable(&sc->intr_tq);
>>> tasklet_disable(&sc->bcon_tasklet);
>>> spin_lock_bh(&sc->sc_pcu_lock);
>>> @@ -331,6 +332,7 @@ static int ath_reset_internal(struct ath_softc *sc, struct
>>> ath9k_channel *hchan)
>>> r = -EIO;
>>> 
>>> out:
>>> + enable_irq(sc->irq);
>>> spin_unlock_bh(&sc->sc_pcu_lock);
>>> tasklet_enable(&sc->bcon_tasklet);
>>> tasklet_enable(&sc->intr_tq);
>> 
>> This part completely blocks the system on a AR9350. Loading the
>> module works but configuring it hangs the system until watchdog restarts it.
> What kernel/software are you running on there? When I committed this
> patch to OpenWrt, it uncovered IRQ handling bugs in MIPS kernel code
> (both generic and in the ath79 platform code).
> 
> You can find the fixes that I've made here:
> http://git.openwrt.org/?p=openwrt.git;a=blob_plain;f=target/linux/generic/patches-3.14/130-mips_cpu_irq_disable.patch
> http://git.openwrt.org/?p=openwrt.git;a=blob_plain;f=target/linux/ar71xx/patches-3.14/736-MIPS-ath79-fix-chained-irq-disable.patch
> 
> I've already submitted the first one to linux-mips.
> 
> - Felix

Thank you, these patches fixed the problem.

Rico