Re: [PATCH v2 2/4] fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once()

From: Luis Chamberlain
Date: Thu Mar 12 2020 - 20:58:36 EST


On Thu, Mar 12, 2020 at 01:25:50PM -0700, Eric Biggers wrote:
> From: Eric Biggers <ebiggers@xxxxxxxxxx>
>
> After request_module(), nothing is stopping the module from being
> unloaded until someone takes a reference to it via try_get_module().
>
> The WARN_ONCE() in get_fs_type() is thus user-reachable, via userspace
> running 'rmmod' concurrently.
>
> Since WARN_ONCE() is for kernel bugs only, not for user-reachable
> situations, downgrade this warning to pr_warn_once().
>
> Cc: stable@xxxxxxxxxxxxxxx
> Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Cc: Jeff Vander Stoep <jeffv@xxxxxxxxxx>
> Cc: Jessica Yu <jeyu@xxxxxxxxxx>
> Cc: Kees Cook <keescook@xxxxxxxxxxxx>
> Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
> Cc: NeilBrown <neilb@xxxxxxxx>
> Signed-off-by: Eric Biggers <ebiggers@xxxxxxxxxx>

Acked-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>

Luis