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| author | Vladimir Oltean <olteanv@gmail.com> | 2019-09-29 02:01:39 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-09-30 18:32:20 -0700 |
| commit | 68ce6688a5baefde30914fc07fc27292dbbe8320 (patch) | |
| tree | effbc924ac1ced53a241d80025857565ffa18777 /net/sched/sch_taprio.c | |
| parent | 68501df92d116b760777a2cfda314789f926476f (diff) | |
| download | lwn-68ce6688a5baefde30914fc07fc27292dbbe8320.tar.gz lwn-68ce6688a5baefde30914fc07fc27292dbbe8320.zip | |
net: sched: taprio: Fix potential integer overflow in taprio_set_picos_per_byte
The speed divisor is used in a context expecting an s64, but it is
evaluated using 32-bit arithmetic.
To avoid that happening, instead of multiplying by 1,000,000 in the
first place, simplify the fraction and do a standard 32 bit division
instead.
Fixes: f04b514c0ce2 ("taprio: Set default link speed to 10 Mbps in taprio_set_picos_per_byte")
Reported-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/sched/sch_taprio.c')
| -rw-r--r-- | net/sched/sch_taprio.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 2f7b34205c82..2aab46ada94f 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1048,8 +1048,7 @@ static void taprio_set_picos_per_byte(struct net_device *dev, speed = ecmd.base.speed; skip: - picos_per_byte = div64_s64(NSEC_PER_SEC * 1000LL * 8, - speed * 1000 * 1000); + picos_per_byte = (USEC_PER_SEC * 8) / speed; atomic64_set(&q->picos_per_byte, picos_per_byte); netdev_dbg(dev, "taprio: set %s's picos_per_byte to: %lld, linkspeed: %d\n", |