linux-kernel - Re: [PATCH v2] regmap: slimbus: fix bus_context pointer in regmap init calls

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Message-ID: <affa81cd-6f44-4408-9b07-f635b00cfaa6@kernel.org>
Date: Thu, 23 Oct 2025 17:49:51 +0100
From: Srinivas Kandagatla <srini@...nel.org>
To: Alexey Klimov <alexey.klimov@...aro.org>, broonie@...nel.org,
 gregkh@...uxfoundation.org, srini@...nel.org
Cc: rafael@...nel.org, dakr@...nel.org, make24@...as.ac.cn, steev@...i.org,
 dmitry.baryshkov@....qualcomm.com, linux-kernel@...r.kernel.org,
 linux-sound@...r.kernel.org, linux-arm-msm@...r.kernel.org,
 abel.vesa@...aro.org, stable@...r.kernel.org
Subject: Re: [PATCH v2] regmap: slimbus: fix bus_context pointer in regmap
 init calls



On 10/22/25 9:10 PM, Alexey Klimov wrote:
> Commit 4e65bda8273c ("ASoC: wcd934x: fix error handling in
> wcd934x_codec_parse_data()") revealed the problem in the slimbus regmap.
> That commit breaks audio playback, for instance, on sdm845 Thundercomm
> Dragonboard 845c board:
> 
>  Unable to handle kernel paging request at virtual address ffff8000847cbad4
>  ...
>  CPU: 5 UID: 0 PID: 776 Comm: aplay Not tainted 6.18.0-rc1-00028-g7ea30958b305 #11 PREEMPT
>  Hardware name: Thundercomm Dragonboard 845c (DT)
>  ...
>  Call trace:
>   slim_xfer_msg+0x24/0x1ac [slimbus] (P)
>   slim_read+0x48/0x74 [slimbus]
>   regmap_slimbus_read+0x18/0x24 [regmap_slimbus]
>   _regmap_raw_read+0xe8/0x174
>   _regmap_bus_read+0x44/0x80
>   _regmap_read+0x60/0xd8
>   _regmap_update_bits+0xf4/0x140
>   _regmap_select_page+0xa8/0x124
>   _regmap_raw_write_impl+0x3b8/0x65c
>   _regmap_bus_raw_write+0x60/0x80
>   _regmap_write+0x58/0xc0
>   regmap_write+0x4c/0x80
>   wcd934x_hw_params+0x494/0x8b8 [snd_soc_wcd934x]
>   snd_soc_dai_hw_params+0x3c/0x7c [snd_soc_core]
>   __soc_pcm_hw_params+0x22c/0x634 [snd_soc_core]
>   dpcm_be_dai_hw_params+0x1d4/0x38c [snd_soc_core]
>   dpcm_fe_dai_hw_params+0x9c/0x17c [snd_soc_core]
>   snd_pcm_hw_params+0x124/0x464 [snd_pcm]
>   snd_pcm_common_ioctl+0x110c/0x1820 [snd_pcm]
>   snd_pcm_ioctl+0x34/0x4c [snd_pcm]
>   __arm64_sys_ioctl+0xac/0x104
>   invoke_syscall+0x48/0x104
>   el0_svc_common.constprop.0+0x40/0xe0
>   do_el0_svc+0x1c/0x28
>   el0_svc+0x34/0xec
>   el0t_64_sync_handler+0xa0/0xf0
>   el0t_64_sync+0x198/0x19c
> 
> The __devm_regmap_init_slimbus() started to be used instead of
> __regmap_init_slimbus() after the commit mentioned above and turns out
> the incorrect bus_context pointer (3rd argument) was used in
> __devm_regmap_init_slimbus(). It should be just "slimbus" (which is equal
> to &slimbus->dev). Correct it. The wcd934x codec seems to be the only or
> the first user of devm_regmap_init_slimbus() but we should fix it till
> the point where __devm_regmap_init_slimbus() was introduced therefore
> two "Fixes" tags.
> 
> While at this, also correct the same argument in __regmap_init_slimbus().
> 
> Fixes: 4e65bda8273c ("ASoC: wcd934x: fix error handling in wcd934x_codec_parse_data()")
> Fixes: 7d6f7fb053ad ("regmap: add SLIMbus support")
> Cc: stable@...r.kernel.org
> Cc: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
> Cc: Ma Ke <make24@...as.ac.cn>
> Cc: Steev Klimaszewski <steev@...i.org>
> Cc: Srinivas Kandagatla <srini@...nel.org>
> Reviewed-by: Abel Vesa <abel.vesa@...aro.org>
> Signed-off-by: Alexey Klimov <alexey.klimov@...aro.org>
> ---
> 
> The patch/fix is for the current 6.18 development cycle
> since it fixes the regression introduced in 6.18.0-rc1.
> 
> Changes in v2:
>  - &slimbus->dev replaced with just "slimbus", no functional change
>  (as suggested by Dmitry);
>  - the same argument in __regmap_init_slimbus() was replaced with
>  "slimbus" (as suggested by Dmitry);
>  - reduced the backtrace log in the commit message (as suggested by Mark);
>  - corrected subject/title, few typos, added mention of non-managed init
>  func change, rephrased smth;
>  - added Reviewed-by tag from Abel.
> 
> Prev version: https://lore.kernel.org/linux-sound/20251020015557.1127542-1-alexey.klimov@linaro.org/
> 
>  drivers/base/regmap/regmap-slimbus.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 

In case Mark if you want to pick this up,

Acked-by: Srinivas Kandagatla <srini@...nel.org>


> diff --git a/drivers/base/regmap/regmap-slimbus.c b/drivers/base/regmap/regmap-slimbus.c
> index 54eb7d227cf4..e523fae73004 100644
> --- a/drivers/base/regmap/regmap-slimbus.c
> +++ b/drivers/base/regmap/regmap-slimbus.c
> @@ -48,8 +48,7 @@ struct regmap *__regmap_init_slimbus(struct slim_device *slimbus,
>  	if (IS_ERR(bus))
>  		return ERR_CAST(bus);
>  
> -	return __regmap_init(&slimbus->dev, bus, &slimbus->dev, config,
> -			     lock_key, lock_name);
> +	return __regmap_init(&slimbus->dev, bus, slimbus, config, lock_key, lock_name);
>  }
>  EXPORT_SYMBOL_GPL(__regmap_init_slimbus);
>  
> @@ -63,8 +62,7 @@ struct regmap *__devm_regmap_init_slimbus(struct slim_device *slimbus,
>  	if (IS_ERR(bus))
>  		return ERR_CAST(bus);
>  
> -	return __devm_regmap_init(&slimbus->dev, bus, &slimbus, config,
> -				  lock_key, lock_name);
> +	return __devm_regmap_init(&slimbus->dev, bus, slimbus, config, lock_key, lock_name);
>  }
>  EXPORT_SYMBOL_GPL(__devm_regmap_init_slimbus);
>