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From: Sergey Shtylyov <s.shtylyov@omp.ru>
To: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
<davem@davemloft.net>, <kuba@kernel.org>
Cc: <netdev@vger.kernel.org>, <linux-renesas-soc@vger.kernel.org>
Subject: Re: [PATCH] net: renesas: sh_eth: Fix freeing wrong tx descriptor
Date: Tue, 7 Sep 2021 22:29:56 +0300 [thread overview]
Message-ID: <a610ac4b-eeb9-50c2-4b88-0d77d1c83d47@omp.ru> (raw)
In-Reply-To: <20210907112940.967985-1-yoshihiro.shimoda.uh@renesas.com>
On 9/7/21 2:29 PM, Yoshihiro Shimoda wrote:
> The cur_tx counter must be incremented after TACT bit of
> txdesc->status was set. However, a CPU is possible to reorder
> instructions and/or memory accesses between cur_tx and
> txdesc->status. And then, if TX interrupt happened at such a
> timing, the sh_eth_tx_free() may free the descriptor wrongly.
> So, add wmb() before cur_tx++.
Not dma_wmb()? :-)
> Otherwise NETDEV WATCHDOG timeout is possible to happen.
>
> Fixes: 86a74ff21a7a ("net: sh_eth: add support for Renesas SuperH Ethernet")
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
[...]
MBR, Sergey
next prev parent reply other threads:[~2021-09-07 19:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-07 11:29 Yoshihiro Shimoda
2021-09-07 13:10 ` patchwork-bot+netdevbpf
2021-09-07 19:29 ` Sergey Shtylyov [this message]
2021-09-08 5:45 ` Yoshihiro Shimoda
2021-09-08 9:46 ` Sergey Shtylyov
2021-09-08 11:43 ` Yoshihiro Shimoda
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