Re: [PATCH v5.1-rc] iwlwifi: make locking in iwl_mvm_tx_mpdu() BH-safe
- Date: Mon, 15 Apr 2019 13:33:47 +0200 (CEST)
- From: Jiri Kosina <jikos@xxxxxxxxxx>
- Subject: Re: [PATCH v5.1-rc] iwlwifi: make locking in iwl_mvm_tx_mpdu() BH-safe
On Mon, 15 Apr 2019, Johannes Berg wrote:
> (FWIW, would be good to cc linux-wireless, but no need for linux-kernel
> I guess :-) )
Hm, no idea where I lost that ML from the get_maintainer output, sorry for
> > iwl_mvm_sta->lock can be taken from BH, and therefore BH must be
> > disabled if taking it from other contexts.
> > This fixes the lockdep warning below.
> I don't think this is the right fix.
> The only problem is this path:
Agreed, that seems to be the only culprit.
> > SOFTIRQ-ON-W at:
> > _raw_spin_lock+0x35/0x50
> > iwl_mvm_tx_mpdu+0xae/0x5f0 [iwlmvm]
> > iwl_mvm_tx_skb+0x200/0x470 [iwlmvm]
> > iwl_mvm_mac_itxq_xmit+0xd5/0x1f0 [iwlmvm]
> > iwl_mvm_add_new_dqa_stream_wk+0x34c/0x910 [iwlmvm]
> > process_one_work+0x1f0/0x5b0
> which I believe we just made use local_bh_disable() since there are
> other reasons as well for that, IIRC.
> Yes, here's the fix:
> It's on the way upstream.
If there are other reasons why disable BH for the whole function (are
there?), then this bigger hammer works as well of course.
Tested-by: Jiri Kosina <jkosina@xxxxxxx>
> Thanks for the patch/report though!