Re: [PATCH] hwrng: core - reject unknown RNG names

[Andy Shevchenko]

On Thu, Sep 24, 2026 at 11:21:13PM +0200, Thorsten Blum wrote:
> In rng_current_store(), err is 0 after successfully locking rng_mutex,
> and if the requested RNG name cannot be found, the function reports
> success even though the current RNG was not changed.
> 
> Set err = -ENODEV before searching the RNG list to reject unknown names.

Yeah, from the

> Fixes: 142a27f0a731 ("hwrng: core - Reset user selected rng by writing "" to rng_current")

it looks like it was the intention, but the mutex_lock_interruptible() rewrites
an error code. That's a good example on why I often tell people to decouple
assignment from the definition and the very same issue might happen and would be
hard to debug later on. Surprisingly this happened in the same patch...

Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>

-- 
With Best Regards,
Andy Shevchenko