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    Subject[PATCH 3.16 150/410] staging: rts5208: Fix "seg_no" calculation in reset_ms_card()
    3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Dan Carpenter <dan.carpenter@oracle.com>

    commit 7f7aeea7cf30368b9fdb86dcc9d2c8a3ebc65dfb upstream.

    I get some static checker warnings like this:

    drivers/staging/rts5208/ms.c:2607 ms_build_l2p_tbl()
    error: buffer underflow 'ms_card->segment' (-1)-16

    The problem is that we memset "ms_card" to zero at the start of the
    reset_ms_card() function. That means that when we try to calculate
    "ms_card->total_block / 512 - 1" then it's just always -1. The fix is
    to calculate "seg_no" before doing the memset().

    This is a static checker fix, and I am not able to test it. My theory
    is that reset_ms_card() gets very little testing which is why this bug
    exists.

    Fixes: fa590c222fba ("staging: rts5208: add support for rts5208 and rts5288")
    Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    [bwh: Backported to 3.16: adjust context]
    Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
    ---
    drivers/staging/rts5208/ms.c | 3 ++-
    1 file changed, 2 insertions(+), 1 deletion(-)

    --- a/drivers/staging/rts5208/ms.c
    +++ b/drivers/staging/rts5208/ms.c
    @@ -2397,6 +2397,7 @@ BUILD_FAIL:
    int reset_ms_card(struct rtsx_chip *chip)
    {
    struct ms_info *ms_card = &(chip->ms_card);
    + int seg_no = ms_card->total_block / 512 - 1;
    int retval;

    memset(ms_card, 0, sizeof(struct ms_info));
    @@ -2430,7 +2431,7 @@ int reset_ms_card(struct rtsx_chip *chip
    /* Build table for the last segment,
    * to check if L2P table block exists, erasing it
    */
    - retval = ms_build_l2p_tbl(chip, ms_card->total_block / 512 - 1);
    + retval = ms_build_l2p_tbl(chip, seg_no);
    if (retval != STATUS_SUCCESS)
    TRACE_RET(chip, STATUS_FAIL);
    }
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