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Subjectpm_runtime_resume_and_get in .remove callbacks
Hello,

there is a big bunch of kernel drivers (here:
drivers/i2c/busses/i2c-sprd.c) that have a remove callback that looks as
follows:

static int sprd_i2c_remove(struct platform_device *pdev)
{
struct sprd_i2c *i2c_dev = platform_get_drvdata(pdev);
int ret;

ret = pm_runtime_resume_and_get(i2c_dev->dev);
if (ret < 0)
return ret;

i2c_del_adapter(&i2c_dev->adap);
clk_disable_unprepare(i2c_dev->clk);

pm_runtime_put_noidle(i2c_dev->dev);
pm_runtime_disable(i2c_dev->dev);

return 0;
}

If pm_runtime_resume_and_get fails, the i2c adapter isn't removed, but
as the memory backing i2c_dev goes away---it was allocated using
devm_kzalloc in .probe()---the next i2c action will probably access
freed memory.

I'm not familiar enough with pm-runtime stuff, but wonder what
can/should be done about that. The obvious (to me) candidates are:

- log an error if pm_runtime_resume_and_get() fails, but continue to
clean up
- don't check the return value at all

What do you think?

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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