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From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [BUG] fs: f2fs: Possible null-pointer dereferences in
 update_general_status()
To:     jaegeuk@kernel.org, yuchao0@huawei.com
Cc:     linux-f2fs-devel@lists.sourceforge.net,
        linux-kernel@vger.kernel.org
Message-ID: <f577be2f-fc2f-9ef8-2c6c-9c247123b1ad@gmail.com>
Date:   Thu, 25 Jul 2019 17:49:44 +0800
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In update_general_status(), there are two if statements to
check whether SM_I(sbi) is NULL:
LINE 70:     if (SM_I(sbi) && SM_I(sbi)->fcc_info)
LINE 78:     if (SM_I(sbi) && SM_I(sbi)->dcc_info)

When SM_I(sbi) is NULL, it is used at some places, such as:
LINE 88: reserved_segments(sbi)
                   return SM_I(sbi)->reserved_segments;
LINE 89: overprovision_segments(sbi)
                   return SM_I(sbi)->ovp_segments;
LINE 112: MAIN_SEGS(sbi)
                     (SM_I(sbi)->main_segments)

Thus, possible null-pointer dereferences may occur.

These bugs are found by a static analysis tool STCheck written by us.

I do not know how to correctly fix these bugs, so I only report them.


Best wishes,
Jia-Ju Bai