Commit 54d34165 authored by Dan Carpenter's avatar Dan Carpenter Committed by Paolo Abeni
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net/mlx4_en: Prevent potential integer overflow calculating Hz 



The "freq" variable is in terms of MHz and "max_val_cycles" is in terms
of Hz.  The fact that "max_val_cycles" is a u64 suggests that support
for high frequency is intended but the "freq_khz * 1000" would overflow
the u32 type if we went above 4GHz.  Use unsigned long long type for the
mutliplication to prevent that.

Fixes: 31c128b6 ("net/mlx4_en: Choose time-stamping shift value according to HW frequency")
Signed-off-by: default avatarDan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: default avatarSimon Horman <horms@kernel.org>
Link: https://patch.msgid.link/aDbFHe19juIJKjsb@stanley.mountain


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent ba99c627

drivers/net/ethernet/mellanox/mlx4/en_clock.c

+1 −1
Original line number Diff line number Diff line
@@ -249,7 +249,7 @@ static const struct ptp_clock_info mlx4_en_ptp_clock_info = { 
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 max_val_cycles = freq_khz * 1000ULL * MLX4_EN_WRAP_AROUND_SEC;

	u64 max_val_cycles_rounded = 1ULL << fls64(max_val_cycles - 1);

	/* calculate max possible multiplier in order to fit in 64bit */

	u64 max_mul = div64_u64(ULLONG_MAX, max_val_cycles_rounded);