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| author | Yamin Friedman <yaminf@mellanox.com> | 2019-07-23 10:22:47 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-07-25 11:34:39 -0700 |
| commit | f06d0ca45827a5790d7508de4759aed976933d4d (patch) | |
| tree | f3129a536a3e647dc47f0acc9f9fcfd5230fbf4b /lib/dim | |
| parent | c8ec4632c6ac9cda0e8c3d51aa41eeab66585bd5 (diff) | |
| download | lwn-f06d0ca45827a5790d7508de4759aed976933d4d.tar.gz lwn-f06d0ca45827a5790d7508de4759aed976933d4d.zip | |
linux/dim: Fix overflow in dim calculation
While using net_dim, a dim_sample was used without ever initializing the
comps value. Added use of DIV_ROUND_DOWN_ULL() to prevent potential
overflow, it should not be a problem to save the final result in an int
because after the division by epms the value should not be larger than a
few thousand.
[ 1040.127124] UBSAN: Undefined behaviour in lib/dim/dim.c:78:23
[ 1040.130118] signed integer overflow:
[ 1040.131643] 134718714 * 100 cannot be represented in type 'int'
Fixes: 398c2b05bbee ("linux/dim: Add completions count to dim_sample")
Signed-off-by: Yamin Friedman <yaminf@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Acked-by: Saeed Mahameed <saeedm@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'lib/dim')
| -rw-r--r-- | lib/dim/dim.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/lib/dim/dim.c b/lib/dim/dim.c index 439d641ec796..38045d6d0538 100644 --- a/lib/dim/dim.c +++ b/lib/dim/dim.c @@ -74,8 +74,8 @@ void dim_calc_stats(struct dim_sample *start, struct dim_sample *end, delta_us); curr_stats->cpms = DIV_ROUND_UP(ncomps * USEC_PER_MSEC, delta_us); if (curr_stats->epms != 0) - curr_stats->cpe_ratio = - (curr_stats->cpms * 100) / curr_stats->epms; + curr_stats->cpe_ratio = DIV_ROUND_DOWN_ULL( + curr_stats->cpms * 100, curr_stats->epms); else curr_stats->cpe_ratio = 0; |