Messages in this thread Patch in this message | | | Date | Wed, 18 Mar 2020 16:43:15 +0100 | From | Jessica Yu <> | Subject | Re: [PATCH v3 2/5] fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once() |
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+++ Eric Biggers [14/03/20 14:34 -0700]: >From: Eric Biggers <ebiggers@google.com> > >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(). > >Acked-by: Luis Chamberlain <mcgrof@kernel.org> >Cc: stable@vger.kernel.org >Cc: Alexei Starovoitov <ast@kernel.org> >Cc: Andrew Morton <akpm@linux-foundation.org> >Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> >Cc: Jeff Vander Stoep <jeffv@google.com> >Cc: Jessica Yu <jeyu@kernel.org> >Cc: Kees Cook <keescook@chromium.org> >Cc: NeilBrown <neilb@suse.com> >Signed-off-by: Eric Biggers <ebiggers@google.com> >--- > fs/filesystems.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > >diff --git a/fs/filesystems.c b/fs/filesystems.c >index 77bf5f95362da..90b8d879fbaf3 100644 >--- a/fs/filesystems.c >+++ b/fs/filesystems.c >@@ -272,7 +272,9 @@ struct file_system_type *get_fs_type(const char *name) > fs = __get_fs_type(name, len); > if (!fs && (request_module("fs-%.*s", len, name) == 0)) { > fs = __get_fs_type(name, len); >- WARN_ONCE(!fs, "request_module fs-%.*s succeeded, but still no fs?\n", len, name); >+ if (!fs) >+ pr_warn_once("request_module fs-%.*s succeeded, but still no fs?\n", >+ len, name);
Hm, what was the rationale for warning only once again? It might be useful for debugging issues to see each instance of request_module() failure (and with which fs). However, I don't have a concrete use case to support this argument, so:
Reviewed-by: Jessica Yu <jeyu@kernel.org>
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