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    Subject[PATCH 5.18 514/879] hwmon: (dimmtemp) Fix bitmap handling
    Date
    From: Guenter Roeck <linux@roeck-us.net>

    [ Upstream commit 9baabde04de64137e86b39112c6259f3da512bd6 ]

    Building arm:allmodconfig may fail with the following error.

    In function 'fortify_memcpy_chk',
    inlined from 'bitmap_copy' at include/linux/bitmap.h:261:2,
    inlined from 'bitmap_copy_clear_tail' at include/linux/bitmap.h:270:2,
    inlined from 'bitmap_from_u64' at include/linux/bitmap.h:622:2,
    inlined from 'check_populated_dimms' at
    drivers/hwmon/peci/dimmtemp.c:284:2:
    include/linux/fortify-string.h:344:25: error:
    call to '__write_overflow_field' declared with attribute warning:
    detected write beyond size of field (1st parameter)

    The problematic code is
    bitmap_from_u64(priv->dimm_mask, dimm_mask);

    dimm_mask is declared as u64, but the bitmap in priv->dimm_mask is only
    24 bit wide. On 32-bit systems, this results in writes over the end of
    the bitmap.

    Fix the problem by using u32 instead of u64 for dimm_mask. This is
    currently sufficient, and a compile time check to ensure that the number
    of dimms does not exceed the bit map size is already in place.

    Fixes: 73bc1b885dae ("hwmon: peci: Add dimmtemp driver")
    Cc: Iwona Winiarska <iwona.winiarska@intel.com>
    Reviewed-by: Iwona Winiarska <iwona.winiarska@intel.com>
    Signed-off-by: Guenter Roeck <linux@roeck-us.net>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/hwmon/peci/dimmtemp.c | 6 +++---
    1 file changed, 3 insertions(+), 3 deletions(-)

    diff --git a/drivers/hwmon/peci/dimmtemp.c b/drivers/hwmon/peci/dimmtemp.c
    index c8222354c005..53e58a9c28ea 100644
    --- a/drivers/hwmon/peci/dimmtemp.c
    +++ b/drivers/hwmon/peci/dimmtemp.c
    @@ -219,7 +219,7 @@ static int check_populated_dimms(struct peci_dimmtemp *priv)
    int chan_rank_max = priv->gen_info->chan_rank_max;
    int dimm_idx_max = priv->gen_info->dimm_idx_max;
    u32 chan_rank_empty = 0;
    - u64 dimm_mask = 0;
    + u32 dimm_mask = 0;
    int chan_rank, dimm_idx, ret;
    u32 pcs;

    @@ -278,9 +278,9 @@ static int check_populated_dimms(struct peci_dimmtemp *priv)
    return -EAGAIN;
    }

    - dev_dbg(priv->dev, "Scanned populated DIMMs: %#llx\n", dimm_mask);
    + dev_dbg(priv->dev, "Scanned populated DIMMs: %#x\n", dimm_mask);

    - bitmap_from_u64(priv->dimm_mask, dimm_mask);
    + bitmap_from_arr32(priv->dimm_mask, &dimm_mask, DIMM_NUMS_MAX);

    return 0;
    }
    --
    2.35.1


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