Commit 26c5d78c authored by Eric Biggers's avatar Eric Biggers Committed by Linus Torvalds
Browse files

fs/filesystems.c: downgrade user-reachable WARN_ONCE() to pr_warn_once()

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().

Keep it printed once only, since the intent of this warning is to detect
a bug in modprobe at boot time.  Printing the warning more than once
wouldn't really provide any useful extra information.

Fixes: 41124db8

 ("fs: warn in case userspace lied about modprobe return")
Signed-off-by: default avatarEric Biggers <>
Signed-off-by: default avatarAndrew Morton <>
Reviewed-by: default avatarJessica Yu <>
Cc: Alexei Starovoitov <>
Cc: Greg Kroah-Hartman <>
Cc: Jeff Vander Stoep <>
Cc: Jessica Yu <>
Cc: Kees Cook <>
Cc: Luis Chamberlain <>
Cc: NeilBrown <>
Cc: <>		[4.13+]

Signed-off-by: default avatarLinus Torvalds <>
parent d7d27cfc
......@@ -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);
if (dot && fs && !(fs->fs_flags & FS_HAS_SUBTYPE)) {
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