linux-kernel - Re: [PATCH] mm: initialize return of vm_insert

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Message-ID: <20200703145454.GH25523@casper.infradead.org>
Date:   Fri, 3 Jul 2020 15:54:54 +0100
From:   Matthew Wilcox <willy@...radead.org>
To:     trix@...hat.com
Cc:     akpm@...ux-foundation.org, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm: initialize return of vm_insert_pages

On Fri, Jul 03, 2020 at 07:52:02AM -0700, trix@...hat.com wrote:
> From: Tom Rix <trix@...hat.com>
> 
> clang static analysis reports a garbage return
> 
> In file included from mm/memory.c:84:
> mm/memory.c:1612:2: warning: Undefined or garbage value returned to caller [core.uninitialized.UndefReturn]
>         return err;
>         ^~~~~~~~~~
> 
> The setting of err depends on a loop executing.
> So initialize err.

I'd argue that returning zero is wrong.  If someone's asked to insert
zero pages, that's a nonsense thing to do so it should return -EINVAL..