linux-kernel - [PATCH -next] fanotify: Fix the checks in fanotify_fsid

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Date:   Fri, 27 Mar 2020 10:10:30 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Jan Kara <jack@...e.cz>
Cc:     Amir Goldstein <amir73il@...il.com>, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, clang-built-linux@...glegroups.com,
        Nathan Chancellor <natechancellor@...il.com>
Subject: [PATCH -next] fanotify: Fix the checks in fanotify_fsid_equal

Clang warns:

fs/notify/fanotify/fanotify.c:28:23: warning: self-comparison always
evaluates to true [-Wtautological-compare]
        return fsid1->val[0] == fsid1->val[0] && fsid2->val[1] == fsid2->val[1];
                             ^
fs/notify/fanotify/fanotify.c:28:57: warning: self-comparison always
evaluates to true [-Wtautological-compare]
        return fsid1->val[0] == fsid1->val[0] && fsid2->val[1] == fsid2->val[1];
                                                               ^
2 warnings generated.

The intention was clearly to compare val[0] and val[1] in the two
different fsid structs. Fix it otherwise this function always returns
true.

Fixes: afc894c784c8 ("fanotify: Store fanotify handles differently")
Link: https://github.com/ClangBuiltLinux/linux/issues/952
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---
 fs/notify/fanotify/fanotify.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/notify/fanotify/fanotify.c b/fs/notify/fanotify/fanotify.c
index 7a889da1ee12..cb54ecdb3fb9 100644
--- a/fs/notify/fanotify/fanotify.c
+++ b/fs/notify/fanotify/fanotify.c
@@ -25,7 +25,7 @@ static bool fanotify_path_equal(struct path *p1, struct path *p2)
 static inline bool fanotify_fsid_equal(__kernel_fsid_t *fsid1,
 				       __kernel_fsid_t *fsid2)
 {
-	return fsid1->val[0] == fsid1->val[0] && fsid2->val[1] == fsid2->val[1];
+	return fsid1->val[0] == fsid2->val[0] && fsid1->val[1] == fsid2->val[1];
 }
 
 static bool fanotify_fh_equal(struct fanotify_fh *fh1,
-- 
2.26.0