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| author | Eric Biggers <ebiggers@google.com> | 2020-04-10 14:33:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-04-10 15:36:22 -0700 |
| commit | 26c5d78c976ca298e59a56f6101a97b618ba3539 (patch) | |
| tree | 8d16411e4fb2fdd3e2beb577f571ea3fb2f42025 /fs | |
| parent | d7d27cfc5cf0766a26a8f56868c5ad5434735126 (diff) | |
| download | linux-26c5d78c976ca298e59a56f6101a97b618ba3539.tar.bz2 | |
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>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/filesystems.c | 4 |
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)) { |