Messages in this thread Patch in this message | | | Date | Tue, 6 Feb 2018 10:46:59 -0600 | From | "Gustavo A. R. Silva" <> | Subject | [PATCH v3 1/8] rtl2832: use 64-bit arithmetic instead of 32-bit in rtl2832_set_frontend |
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Add suffix ULL to constant 7 in order to give the compiler complete information about the proper arithmetic to use. Notice that this constant is used in a context that expects an expression of type u64 (64 bits, unsigned).
The expression dev->pdata->clk * 7 is currently being evaluated using 32-bit arithmetic.
Addresses-Coverity-ID: 1271223 ("Unintentional integer overflow") Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com> --- Changes in v2: - Update subject and changelog to better reflect the proposed code changes. - Add suffix ULL to constant instead of casting a variable.
Changes in v3: - Mention the specific Coverity report in the commit message.
drivers/media/dvb-frontends/rtl2832.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/media/dvb-frontends/rtl2832.c b/drivers/media/dvb-frontends/rtl2832.c index 94bf5b7..fa3b816 100644 --- a/drivers/media/dvb-frontends/rtl2832.c +++ b/drivers/media/dvb-frontends/rtl2832.c @@ -498,7 +498,7 @@ static int rtl2832_set_frontend(struct dvb_frontend *fe) * RSAMP_RATIO = floor(CrystalFreqHz * 7 * pow(2, 22) * / ConstWithBandwidthMode) */ - num = dev->pdata->clk * 7; + num = dev->pdata->clk * 7ULL; num *= 0x400000; num = div_u64(num, bw_mode); resamp_ratio = num & 0x3ffffff; @@ -511,7 +511,7 @@ static int rtl2832_set_frontend(struct dvb_frontend *fe) * / (CrystalFreqHz * 7)) */ num = bw_mode << 20; - num2 = dev->pdata->clk * 7; + num2 = dev->pdata->clk * 7ULL; num = div_u64(num, num2); num = -num; cfreq_off_ratio = num & 0xfffff; -- 2.7.4
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