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To:     shaggy@kernel.org
Cc:     jfs-discussion@lists.sourceforge.net, linux-kernel@vger.kernel.org,
        baijiaju1990@gmail.com
From:   Li Tuo <islituo@gmail.com>
Subject: [BUG] jfs: possible uninitialized-variable access in xtSplitUp()
Message-ID: <6b3b3a56-b77c-aff7-c9f1-94a99d4929d2@gmail.com>
Date:   Sat, 31 Jul 2021 14:31:02 +0800
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Hello,

Our static analysis tool finds a possible uninitialized-variable access 
in the jfs driver in Linux 5.14.0-rc3:

At the beginning of the function xtSplitUp(), the variable rbn is not 
initialized.
If sp->header.flag & BT_ROOT is true,
780:    rc = (sp->header.flag & BT_ROOT) ? xtSplitRoot(tid, ip, split, 
&rmp) : xtSplitPage(tid, ip, split, &rmp, &rbn);

the varialbe rbn will remain uninitialized.
However, it is accessed through:
814:    rcbn = rbn;

I am not quite sure whether this possible uninitialized-variable access 
is real and how to fix it if it is real.
Any feedback would be appreciated, thanks!

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>

Best wishes,
Tuo Li