Re: [PATCH] mm/khugepaged: Initialize index and nr in collapse_file()

[Andrew Morton]

On Tue, 25 Oct 2022 10:34:07 -0700 Nathan Chancellor <nathan@xxxxxxxxxx> wrote:

> Clang warns (trimmed for brevity):
> 
>   mm/khugepaged.c:1729:7: warning: variable 'index' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
>   mm/khugepaged.c:1716:6: warning: variable 'index' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
>   mm/khugepaged.c:1729:7: warning: variable 'nr' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
>   mm/khugepaged.c:1716:6: warning: variable 'nr' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
> 
> There are two goto statements that will use index and nr before they
> have been properly initialized. Zero initialize them so that they can be
> safely used by the tracepoint at the end of the function.

Thanks.  I've actually dropped the offending patch - I'd like a resend
which includes a fix such as this and a good reason for making the
change.