Re: FYI: imx-sdma firmware is not compatible with SLUB slab allocator

From: Jurgen Lambrecht <J.Lambrecht@TELEVIC.com>
To: Robin Gong <yibin.gong@nxp.com>,
	Leonard Crestez <leonard.crestez@nxp.com>,
	Fabio Estevam <festevam@gmail.com>
Cc: Aisheng Dong <aisheng.dong@nxp.com>,
	dl-linux-imx <linux-imx@nxp.com>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"u.kleine-koenig@pengutronix.de" <u.kleine-koenig@pengutronix.de>
Subject: Re: FYI: imx-sdma firmware is not compatible with SLUB slab allocator
Date: Thu, 12 Sep 2019 09:45:50 +0000	[thread overview]
Message-ID: <9a48ca49-4c6f-f17e-3306-6af41d3b162c@televic.com> (raw)
In-Reply-To: <VE1PR04MB66385122B55060CE7919014D89B00@VE1PR04MB6638.eurprd04.prod.outlook.com>

On 9/12/19 4:06 AM, Robin Gong wrote:
> On 2019-9-3 22:32 Jurgen Lambrecht <J.Lambrecht@TELEVIC.com> wrote
>> On 9/3/19 7:57 AM, Robin Gong wrote:
>>
>>> On 2019-8-29 14:24, Jurgen Lambrecht wrote:
>>>> On 8/28/19 4:05 PM, Robin Gong wrote:
>>>>> Could you help check if below commit in your side?
>>>>> commit ebb853b1bd5f659b92c71dc6a9de44cfc37c78c0
>>>>> Author: Lucas Stach<l.stach@pengutronix.de>
>>>>> Date:   Tue Nov 6 03:40:28 2018 +0000
>>>> yes, it's in.
>>>>
>>>> Also the 2 follow-up commits of Lucas Stach:
>>>> 9063f5a99ea76f85935e3e453422d15e7be89b9e and
>>>> 374f384bc66f7a928f11eb20c0518f0f3fc1ffd6.
>> I had also already cherry picked your commit
>> 3f5de4c7e16164a344a905649f08e8a90a68ff9f "dmaengine: imx-sdma:
>> remove BD_INTR for channel0".
>>
>> But also then kernel hangs at loading sdma FW.
>>
>> (this looked the most interesting commit)
> I identified this issue which caused by SDMA_SCRIPT_ADDRS_ARRAY_SIZE_V3
> (41)exceed the structure sdma_script_start_addrs(40) so that illegal memory
> touch, such as slob block header, thus kernel trap into while() loop forever
> in slob_free(). Please see the below code piece in sdma_add_scripts().
>          for (i = 0; i < sdma->script_number; i++)
>                  if (addr_arr[i] > 0)
>                          saddr_arr[i] = addr_arr[i];
> That issue was brought by commit a572460be9cf (dmaengine: imx-sdma:
> Add support for version 3 firmware) because the SDMA_SCRIPT_ADDRS_ARRAY_SIZE_V3
> (38->41 3 scripts added) not align with script number added in
> sdma_script_start_addrs(2 scripts). Please have a try with
> the below patch:
> diff --git a/include/linux/platform_data/dma-imx-sdma.h b/include/linux/platform_data/dma-imx-sdma.h
> index 6eaa53c..30e676b 100644
> --- a/include/linux/platform_data/dma-imx-sdma.h
> +++ b/include/linux/platform_data/dma-imx-sdma.h
> @@ -51,7 +51,10 @@ struct sdma_script_start_addrs {
>          /* End of v2 array */
>          s32 zcanfd_2_mcu_addr;
>          s32 zqspi_2_mcu_addr;
> +       s32 mcu_2_ecspi_addr;
>          /* End of v3 array */
> +       s32 mcu_2_zqspi_addr;
> +       /* End of v4 array */
>   };
>
Yes, this patch solves it! I can now use SLOB slab allocator. I tried 
several reboots and power cycles.
I tried with different dts (without earlycon, without sdma on uart and 
ecspi).
I did not try other kernels, only 4.19.66+fscl with our patches and sdma 
v3.5 built-in.

Thanks and also thanks Uwe for analyzing the assembly,

Jürgen

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