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Message-ID: <20241203100331.00007580@gmail.com>
Date: Tue, 3 Dec 2024 10:03:31 +0800
From: Furong Xu <0x1207@...il.com>
To: Jakub Kicinski <kuba@...nel.org>
Cc: Jon Hunter <jonathanh@...dia.com>, netdev@...r.kernel.org,
linux-stm32@...md-mailman.stormreply.com,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
Alexandre Torgue <alexandre.torgue@...s.st.com>, Jose Abreu
<joabreu@...opsys.com>, "David S. Miller" <davem@...emloft.net>, Eric
Dumazet <edumazet@...gle.com>, Paolo Abeni <pabeni@...hat.com>, Maxime
Coquelin <mcoquelin.stm32@...il.com>, xfr@...look.com, Suraj Jaiswal
<quic_jsuraj@...cinc.com>, Thierry Reding <treding@...dia.com>,
"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH net v1] net: stmmac: TSO: Fix unbalanced DMA map/unmap
for non-paged SKB data
Hi Jakub,
On Mon, 2 Dec 2024 16:33:09 -0800, Jakub Kicinski <kuba@...nel.org> wrote:
> On Thu, 28 Nov 2024 14:45:01 +0800 Furong Xu wrote:
> > > Let me know if you need any more information.
> >
> > [ 149.986210] dwc-eth-dwmac 2490000.ethernet eth0: Tx DMA map failed
> > and
> > [ 245.571688] dwc-eth-dwmac 2490000.ethernet eth0: Tx DMA map failed
> > [ 245.575349] dwc-eth-dwmac 2490000.ethernet eth0: Tx DMA map failed
> > are reported by stmmac_xmit() obviously, but not stmmac_tso_xmit().
> >
> > And these crashes are caused by "Tx DMA map failed", as you can see that
> > current driver code does not handle this kind of failure so well. It is clear
> > that we need to figure out why Tx DMA map failed.
> >
> > This patch corrects the sequence and timing of DMA unmap by waiting all
> > DMA transmit descriptors to be closed by DMA engine for one DMA map in
> > stmmac_tso_xmit(), it never leaks DMA addresses and never introduces
> > other side effect.
> >
> > "Tx DMA map failed" is a weird failure, and I cannot reproduce this failure
> > on my device with DWMAC CORE 5.10a(Synopsys ID: 0x51) and DWXGMAC CORE 3.20a.
>
> Let me repeat Jon's question - is there any info or test you need from
> Jon to make progress with a fix?
>
> If Jon's board worked before and doesn't work with this patch we will
> need *a* fix, if no fix is provided our only choice is revert.
Thanks for your attention to this issue.
I requested Jon to provide more info about "Tx DMA map failed" in previous
reply, and he does not respond yet.
This seems to be a device-specific issue, no fix can be provided without
his reply :(
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