diff options
| author | Eugenia Emantayev <eugenia@mellanox.com> | 2016-10-27 16:27:16 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-11-10 07:41:35 -0800 |
| commit | 61918dbc7efef25294f32431869720d99772b4ca (patch) | |
| tree | 420ea71d243a37233aa18946c8019d4d1b91ed69 /drivers/net | |
| parent | 80176161f4514af9064f75a52a5dece6084128b5 (diff) | |
net/mlx4_en: Resolve dividing by zero in 32-bit system
[ Upstream commit 4850cf4581578216468b7b3c3d06cc5abb0a697d ]
When doing roundup_pow_of_two for large enough number with
bit 31, an overflow will occur and a value equal to 1 will
be returned. In this case 1 will be subtracted from the return
value and division by zero will be reached.
Fixes: 31c128b66e5b ("net/mlx4_en: Choose time-stamping shift value according to HW frequency")
Signed-off-by: Eugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/net')
| -rw-r--r-- | drivers/net/ethernet/mellanox/mlx4/en_clock.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/net/ethernet/mellanox/mlx4/en_clock.c b/drivers/net/ethernet/mellanox/mlx4/en_clock.c index 4dccf7287f0f..52e4ed2f639d 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_clock.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_clock.c @@ -251,8 +251,11 @@ static u32 freq_to_shift(u16 freq) { u32 freq_khz = freq * 1000; u64 max_val_cycles = freq_khz * 1000 * MLX4_EN_WRAP_AROUND_SEC; + u64 tmp_rounded = + roundup_pow_of_two(max_val_cycles) > max_val_cycles ? + roundup_pow_of_two(max_val_cycles) - 1 : UINT_MAX; u64 max_val_cycles_rounded = is_power_of_2(max_val_cycles + 1) ? - max_val_cycles : roundup_pow_of_two(max_val_cycles) - 1; + max_val_cycles : tmp_rounded; /* calculate max possible multiplier in order to fit in 64bit */ u64 max_mul = div_u64(0xffffffffffffffffULL, max_val_cycles_rounded); |