Issue with php version 7.2 in running search

I have an issue with php 7.2 on my wordpress site . My host currently running on php 5.6 and after wordpress send notice that you need to upgrade your php version to 7.2 Cpu usage of my host increased to 90% !!! Thats a huge bug of wordpress

But now i’m gonna upgrade php to 7.2 but after upgrading every thing works fine except searching between products ! When my users using search box trying to find something after wordpress crashes and display this error :
The site is experiencing technical difficulties

The log Stored these lines of error :

#0 /home/censured-site/public_html/wp-includes/template.php(724): require()
#1 /home/censured-site/public_html/wp-includes/template.php(671): load_template('/home/censured...', false)
#2 /home/censured-site/public_html/wp-includes/general-template.php(168): locate_template(Array, true, false)
#3 /home/censured-site/public_html/wp-content/themes/mytheme/search-download.php(89): get_template_part('includes/loop-s...')
#4 /home/censured-site/public_html/wp-includes/template.php(724): require('/home/censured...')
#5 /home/censured-site/public_html/wp-includes/template.php(671): load_template('/home/censured...', false)
#6 /home/censured-site/public_html/wp-includes/general-template.php(168): locate_template(Array, true, false)
#7 /home/censured-site/public_html/wp-content/themes/mytheme/search.php(12): get_template_part('search', 'download')
#8 /home/censured-site/publ in /home/censured-site/public_html/wp-content/themes/mytheme/includes/loop-shop-listings.php on line 24