Hello, Alan, Andrey, all,
(You'll be lucky if Linus doesn't see that. He yells at anybody who suggests adding BUG_ON for anything that doesn't completely crash
Now, may be not )
How is this different from calling kfree() with a NULL argument?
It is not, it is the same case.
What about adding a WARN_ON()? It doesn't crash the kernel and it will be detected and reported by syzbot.
Yes, that would be a great solution.
Sure, we could do that. But would be the point?
We know when usb_find_alt_setting() callers do smth weird and go fix them.
After c9a4cb204e9e, calling usb_find_alt_setting() with a NULL config is no more of a bug than calling kfree() with a NULL pointer.
Yes, exactly.
You wouldn't want to put a WARN_ON in kfree(), would you?
Honestly, in the ideal world I would, again, to be aware when some code does something weird so we know about it. But this world is this world, it needs more performance to the throne of performance.
I have no other arguments except the above, please, feel free to not to accept my patch.
Best regards, Vladis Dronov | Red Hat, Inc. | Product Security Engineer