From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Cochran Subject: Re: [PATCH v2 4/4] net: macb: Add hardware PTP support Date: Wed, 7 Jun 2017 15:28:17 +0200 Message-ID: <20170607132817.GA28329@localhost.localdomain> References: <1496413439-12900-1-git-send-email-rafalo@cadence.com> <1496413690-22826-1-git-send-email-rafalo@cadence.com> <20170606183358.GA25220@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Rafal Ozieblo Cc: David Miller , "nicolas.ferre-AIFe0yeh4nAAvxtiuMwx3w@public.gmane.org" , "netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "harini.katakam-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org" , "andrei.pistirica-UWL1GkI3JZL3oGB3hsPCZA@public.gmane.org" List-Id: devicetree@vger.kernel.org On Wed, Jun 07, 2017 at 11:13:36AM +0000, Rafal Ozieblo wrote: > Please look at following call-stack: > > 1. macb_interrupt() // spin_lock(&bp->lock) is taken > 2. macb_tx_interrupt() > 3. macb_handle_txtstamp() > 4. skb_tstamp_tx() > 5. __skb_tstamp_tx() > 6. skb_may_tx_timestamp() > 7. read_lock_bh() // second lock is taken Well, you can always drop the lock, or postpone the call to skb_tstamp_tx() until after the spin lock is released... > I know that those are different locks and different types. But this could lead > to deadlocks. This is the reason of warning I could see. Can you please post the lockdep splat? Thanks, Richard -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html