[ Upstream commit 81d23d2a24012e448f651e007fac2cfd20a45ce0 ] On 32bit systems, the "4 * max" multiply can overflow. Use kcalloc() to do the allocation to prevent this. Fixes: 44c494c8e30e ("ptp: track available ptp vclocks information") Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Reviewed-by: Heng Qi <hengqi@linux.alibaba.com> Link: https://lore.kernel.org/r/ee8110ed-6619-4bd7-9024-28c1f2ac24f4@moroto.mountain Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>