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From: Maxime Ripard <maxime@cerno.tech>
To: nicolas saenz julienne <nsaenz@kernel.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>,
	Doug Berger <opendmb@gmail.com>,
	bcm-kernel-feedback-list@broadcom.com,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: Kernel Panic in skb_release_data using genet
Date: Wed, 2 Jun 2021 15:28:22 +0200	[thread overview]
Message-ID: <20210602132822.5hw4yynjgoomcfbg@gilmour> (raw)
In-Reply-To: <483c73edf02fa0139aae2b81e797534817655ea0.camel@kernel.org>

On Tue, Jun 01, 2021 at 11:33:18AM +0200, nicolas saenz julienne wrote:
> On Mon, 2021-05-31 at 19:36 -0700, Florian Fainelli wrote:
> > > That is also how I boot my Pi4 at home, and I suspect you are right, if
> > > the VPU does not shut down GENET's DMA, and leaves buffer addresses in
> > > the on-chip descriptors that point to an address space that is managed
> > > totally differently by Linux, then we can have a serious problem and
> > > create some memory corruption when the ring is being reclaimed. I will
> > > run a few experiments to test that theory and there may be a solution
> > > using the SW_INIT reset controller to have a big reset of the controller
> > > before handing it over to the Linux driver.
> > 
> > Adding a WARN_ON(reg & DMA_EN) in bcmgenet_dma_disable() has not shown
> > that the TX or RX DMA have been left running during the hand over from
> > the VPU to the kernel. I checked out drm-misc-next-2021-05-17 to reduce
> > as much as possible the differences between your set-up and my set-up
> > but so far have not been able to reproduce the crash in booting from NFS
> > repeatedly, I will try again.
> 
> FWIW I can reproduce the error too. That said it's rather hard to reproduce,
> something in the order of 1 failure every 20 tries.

Yeah, it looks like it's only from a cold boot and comes in "bursts",
where you would get like 5 in a row and be done with it for a while.

Maxime

  reply	other threads:[~2021-06-02 13:28 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-24 13:01 Kernel Panic in skb_release_data using genet Maxime Ripard
2021-05-24 14:49 ` Florian Fainelli
2021-05-24 15:13   ` Maxime Ripard
2021-05-24 15:37     ` Florian Fainelli
2021-05-28 16:21       ` Florian Fainelli
2021-05-28 16:32         ` Maxime Ripard
2021-05-28 16:48           ` Florian Fainelli
2021-06-01  2:36             ` Florian Fainelli
2021-06-01  9:33               ` nicolas saenz julienne
2021-06-02 13:28                 ` Maxime Ripard [this message]
2021-06-10 21:33                   ` Florian Fainelli
2021-06-25 12:59                     ` Maxime Ripard
2021-07-02 16:49                       ` Florian Fainelli
2021-07-06  8:16                         ` Maxime Ripard
2022-05-13 14:56                     ` Maxime Ripard
2022-05-14 16:35                       ` Florian Fainelli
2022-05-17  7:52                         ` Maxime Ripard
2022-08-12  3:33                           ` Florian Fainelli
2022-08-15  7:07                             ` Maxime Ripard

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