Valid values are 'ON' and 'OFF' 
select @@global.innodb_use_sys_malloc;
@@global.innodb_use_sys_malloc
1
select @@session.innodb_use_sys_malloc;
ERROR HY000: Variable 'innodb_use_sys_malloc' is a GLOBAL variable
show global variables like 'innodb_use_sys_malloc';
Variable_name	Value
innodb_use_sys_malloc	ON
show session variables like 'innodb_use_sys_malloc';
Variable_name	Value
innodb_use_sys_malloc	ON
select * from information_schema.global_variables where variable_name='innodb_use_sys_malloc';
VARIABLE_NAME	VARIABLE_VALUE
INNODB_USE_SYS_MALLOC	ON
select * from information_schema.session_variables where variable_name='innodb_use_sys_malloc';
VARIABLE_NAME	VARIABLE_VALUE
INNODB_USE_SYS_MALLOC	ON
set global innodb_use_sys_malloc=1;
ERROR HY000: Variable 'innodb_use_sys_malloc' is a read only variable
set session innodb_use_sys_malloc=1;
ERROR HY000: Variable 'innodb_use_sys_malloc' is a read only variable
