Re: [PATCH 0/7] char: xillybus: Harden driver and improve code quality

[Greg KH]

On Tue, Jun 30, 2026 at 11:23:23AM +0200, Eli Billauer wrote:
> This patch set consists of several boundary and sanity checks, gaining
> better control of execution flow and fixing minor coding issues. No
> difference is expected in the driver's behavior under normal conditions,
> except for one change that might improve bandwidth performance
> marginally.
> 
> Why all of the sudden? These patches are the result of a comprehensive
> AI-assisted code review, using Deepseek, Kimi Thinking K2.6, ChatGPT,
> and Claude Sonnet 4.6 as plain prompt tools.
> 
> I've spent three weeks in what I call a "reverse rubber duck" session,
> asking these LLMs to find bugs in the code and following up on different
> leads, the vast majority of which turned out to be no more than quack.
> Occasionally the points made by AI were valid, and in others, the mere
> effort to explain why the remark is wrong to the rubber duck led to
> finding real issues.
> 
> Almost none of the fixes suggested by AI were even near the actual
> corrections in this patch set.

I get the following build warning/break when applying these:

drivers/char/xillybus/xillybus_class.c:74:7: error: variable 'rc' is used uninitialized whenever 'if' condition is true [-Werror,-Wsometimes-uninitialized]
   74 |                 if (i > 99) {
      |                     ^~~~~~
drivers/char/xillybus/xillybus_class.c:179:9: note: uninitialized use occurs here
  179 |         return rc;
      |                ^~
drivers/char/xillybus/xillybus_class.c:74:3: note: remove the 'if' if its condition is always false
   74 |                 if (i > 99) {
      |                 ^~~~~~~~~~~~~
   75 |                         dev_err(dev, "Failed to obtain unique unit name\n");
      |                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   76 |                         goto fail_obtain;
      |                         ~~~~~~~~~~~~~~~~~
   77 |                 }
      |                 ~
drivers/char/xillybus/xillybus_class.c:51:8: note: initialize the variable 'rc' to silence this warning
   51 |         int rc;
      |               ^
      |                = 0
1 error generated.

Can you fix that up?

thanks,

greg k-h