Re: [PATCH v3] net: ethernet: ravb: exit if re-initialization fails in tx timeout

[David Miller <davem@davemloft.net>]

From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.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@de.bosch.com>
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> Reviewed-by: Sergei Shtylyov <sergei.shtylyov@gmail.com>

Applied, thank you.