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From: Johannes Berg <johannes@sipsolutions.net>
To: Jiri Kosina <jikos@kernel.org>,
	Emmanuel Grumbach <emmanuel.grumbach@intel.com>,
	Luca Coelho <luciano.coelho@intel.com>
Cc: Intel Linux Wireless <linuxwifi@intel.com>,
	Kalle Valo <kvalo@codeaurora.org>,
	"David S. Miller" <davem@davemloft.net>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5.1-rc] iwlwifi: make locking in iwl_mvm_tx_mpdu() BH-safe
Date: Mon, 15 Apr 2019 13:10:45 +0200	[thread overview]
Message-ID: <24e05607b902e811d1142e3bd345af021fd3d077.camel@sipsolutions.net> (raw)
In-Reply-To: <nycvar.YFH.7.76.1904151300160.9803@cbobk.fhfr.pm>

On Mon, 2019-04-15 at 13:03 +0200, Jiri Kosina wrote:

(FWIW, would be good to cc linux-wireless, but no need for linux-kernel
I guess :-) )

> 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:

>      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:

https://git.kernel.org/pub/scm/linux/kernel/git/kvalo/wireless-drivers.git/commit/?id=f5ae2f932e2f8f4f79796f44832ae8fca26f188a

It's on the way upstream.

Thanks for the patch/report though!

johannes


  reply	other threads:[~2019-04-15 11:11 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-15 11:03 [PATCH v5.1-rc] iwlwifi: make locking in iwl_mvm_tx_mpdu() BH-safe Jiri Kosina
2019-04-15 11:10 ` Johannes Berg [this message]
2019-04-15 11:33   ` Jiri Kosina
2019-04-15 11:37     ` Johannes Berg
2019-04-15 12:06       ` Jiri Kosina
2019-04-15 12:08         ` Johannes Berg
2019-09-11 11:42       ` Jiri Kosina
2019-09-11 12:04         ` Jiri Kosina
2019-09-20 21:34           ` Jiri Kosina
2019-10-01  9:46         ` Johannes Berg
2019-10-01  9:52           ` Johannes Berg

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