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Message-Id: <20200721.153427.1257555808984580585.davem@davemloft.net>
Date: Tue, 21 Jul 2020 15:34:27 -0700 (PDT)
From: David Miller <davem@...emloft.net>
To: yoshihiro.shimoda.uh@...esas.com
Cc: sergei.shtylyov@...il.com, kuba@...nel.org,
dirk.behme@...bosch.com, Shashikant.Suguni@...bosch.com,
netdev@...r.kernel.org, linux-renesas-soc@...r.kernel.org
Subject: Re: [PATCH v3] net: ethernet: ravb: exit if re-initialization
fails in tx timeout
From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Date: Tue, 21 Jul 2020 15:23:12 +0900
> According to the report of [1], this driver is possible to cause
> the following error in ravb_tx_timeout_work().
>
> ravb e6800000.ethernet ethernet: failed to switch device to config mode
>
> This error means that the hardware could not change the state
> from "Operation" to "Configuration" while some tx and/or rx queue
> are operating. After that, ravb_config() in ravb_dmac_init() will fail,
> and then any descriptors will be not allocaled anymore so that NULL
> pointer dereference happens after that on ravb_start_xmit().
>
> To fix the issue, the ravb_tx_timeout_work() should check
> the return values of ravb_stop_dma() and ravb_dmac_init().
> If ravb_stop_dma() fails, ravb_tx_timeout_work() re-enables TX and RX
> and just exits. If ravb_dmac_init() fails, just exits.
>
> [1]
> https://lore.kernel.org/linux-renesas-soc/20200518045452.2390-1-dirk.behme@de.bosch.com/
>
> Reported-by: Dirk Behme <dirk.behme@...bosch.com>
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
> Reviewed-by: Sergei Shtylyov <sergei.shtylyov@...il.com>
Applied, thank you.
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