How to fix phpMyAdmin mkdir permission denied with owner and open_basedir diagnostics

mkdir(): Permission denied in phpMyAdmin is usually a runtime filesystem policy issue, not just a chmod issue.

Diagnose

ps aux | grep php-fpm
php -i | grep -E 'upload_tmp_dir|sys_temp_dir|open_basedir'
ls -ld /tmp
ls -ld /var/lib/php/sessions

Fix

chown -R www-data:www-data /var/lib/php/sessions
chmod 1733 /var/lib/php/sessions

If needed, extend open_basedir to include the temp/session path and restart PHP-FPM.

Validate

• retry import/upload in phpMyAdmin;
• check PHP-FPM/web logs for new denies.

Final takeaway

The right fix is runtime alignment: executing user, writable temp path, and allowed path policy.

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