Re: [PATCH 4.19 123/202] misc: lis3lv02d_i2c: Add missing setting of the reg_ctrl callback

[Hans de Goede <hdegoede@redhat.com>]

Hi Greg,

On 2/21/24 14:07, Greg Kroah-Hartman wrote:
> 4.19-stable review patch.  If anyone has any objections, please let me know.

This is known to cause a regression (WARN triggering on suspend,
possible panic if panic-on-warn is set).

A fix for the regression is pending:

https://lore.kernel.org/regressions/20240220190035.53402-1-hdegoede@redhat.com/T/#u

but it has not been merged yet, so please hold of on merging this 
patch until you can apply both at once.

I see that you are also planning to apply this to other stable
branches. I'm not sure if this is necessary but to be safe
I'll copy and paste this reply to the emails for the other stable
branches.

Regards,

Hans




> 
> ------------------
> 
> From: Hans de Goede <hdegoede@redhat.com>
> 
> [ Upstream commit b1b9f7a494400c0c39f8cd83de3aaa6111c55087 ]
> 
> The lis3lv02d_i2c driver was missing a line to set the lis3_dev's
> reg_ctrl callback.
> 
> lis3_reg_ctrl(on) is called from the init callback, but due to
> the missing reg_ctrl callback the regulators where never turned off
> again leading to the following oops/backtrace when detaching the driver:
> 
> [   82.313527] ------------[ cut here ]------------
> [   82.313546] WARNING: CPU: 1 PID: 1724 at drivers/regulator/core.c:2396 _regulator_put+0x219/0x230
> ...
> [   82.313695] RIP: 0010:_regulator_put+0x219/0x230
> ...
> [   82.314767] Call Trace:
> [   82.314770]  <TASK>
> [   82.314772]  ? _regulator_put+0x219/0x230
> [   82.314777]  ? __warn+0x81/0x170
> [   82.314784]  ? _regulator_put+0x219/0x230
> [   82.314791]  ? report_bug+0x18d/0x1c0
> [   82.314801]  ? handle_bug+0x3c/0x80
> [   82.314806]  ? exc_invalid_op+0x13/0x60
> [   82.314812]  ? asm_exc_invalid_op+0x16/0x20
> [   82.314845]  ? _regulator_put+0x219/0x230
> [   82.314857]  regulator_bulk_free+0x39/0x60
> [   82.314865]  i2c_device_remove+0x22/0xb0
> 
> Add the missing setting of the callback so that the regulators
> properly get turned off again when not used.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> Link: https://lore.kernel.org/r/20231224183402.95640-1-hdegoede@redhat.com
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Signed-off-by: Sasha Levin <sashal@kernel.org>
> ---
>  drivers/misc/lis3lv02d/lis3lv02d_i2c.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/misc/lis3lv02d/lis3lv02d_i2c.c b/drivers/misc/lis3lv02d/lis3lv02d_i2c.c
> index 14b7d539fed6..e8da06020c81 100644
> --- a/drivers/misc/lis3lv02d/lis3lv02d_i2c.c
> +++ b/drivers/misc/lis3lv02d/lis3lv02d_i2c.c
> @@ -164,6 +164,7 @@ static int lis3lv02d_i2c_probe(struct i2c_client *client,
>  	lis3_dev.init	  = lis3_i2c_init;
>  	lis3_dev.read	  = lis3_i2c_read;
>  	lis3_dev.write	  = lis3_i2c_write;
> +	lis3_dev.reg_ctrl = lis3_reg_ctrl;
>  	lis3_dev.irq	  = client->irq;
>  	lis3_dev.ac	  = lis3lv02d_axis_map;
>  	lis3_dev.pm_dev	  = &client->dev;