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authorEric Biggers <ebiggers@google.com>2020-04-10 14:33:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-04-10 15:36:22 -0700
commit26c5d78c976ca298e59a56f6101a97b618ba3539 (patch)
tree8d16411e4fb2fdd3e2beb577f571ea3fb2f42025
parentd7d27cfc5cf0766a26a8f56868c5ad5434735126 (diff)
downloadlinux-stericsson-26c5d78c976ca298e59a56f6101a97b618ba3539.tar.gz
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: 41124db869b7 ("fs: warn in case userspace lied about modprobe return") Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Jessica Yu <jeyu@kernel.org> Cc: Alexei Starovoitov <ast@kernel.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: Luis Chamberlain <mcgrof@kernel.org> Cc: NeilBrown <neilb@suse.com> Cc: <stable@vger.kernel.org> [4.13+] Link: http://lkml.kernel.org/r/20200312202552.241885-3-ebiggers@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/filesystems.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/filesystems.c b/fs/filesystems.c
index 77bf5f95362d..90b8d879fbaf 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);
}
if (dot && fs && !(fs->fs_flags & FS_HAS_SUBTYPE)) {