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This commit is a fixup for MDEV-28762

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This commit is contained in:
Rucha Deodhar
2022-07-25 14:34:44 +05:30
parent f1c8749f46
commit 46ff660883
1 changed files with 21 additions and 9 deletions
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30
sql/item_jsonfunc.cc
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@ -20,6 +20,22 @@
#include "item.h"
#include "sql_parse.h" // For check_stack_overrun
/*
Allocating memory and *also* using it (reading and
writing from it) because some build instructions cause
compiler to optimize out stack_used_up. Since alloca()
here depends on stack_used_up, it doesnt get executed
correctly and causes json_debug_nonembedded to fail
( --error ER_STACK_OVERRUN_NEED_MORE does not occur).
*/
#define ALLOCATE_MEM_ON_STACK(A) do \
{ \
uchar *array= (uchar*)alloca(A); \
array[0]= 1; \
array[0]++; \
array[0] ? array[0]++ : array[0]--; \
} while(0)
/*
Compare ASCII string against the string with the specified
character set.
@ -138,9 +154,10 @@ int json_path_parts_compare(
long arbitrary_var;
long stack_used_up= (available_stack_size(current_thd->thread_stack, &arbitrary_var));
DBUG_EXECUTE_IF("json_check_min_stack_requirement",
{alloca(my_thread_stack_size-stack_used_up-STACK_MIN_SIZE);});
{ALLOCATE_MEM_ON_STACK(my_thread_stack_size-stack_used_up-STACK_MIN_SIZE);});
if (check_stack_overrun(current_thd, STACK_MIN_SIZE , NULL))
return 1;
while (a <= a_end)
{
if (b > b_end)
@ -1139,15 +1156,10 @@ static int check_contains(json_engine_t *js, json_engine_t *value)
long arbitrary_var;
long stack_used_up= (available_stack_size(current_thd->thread_stack, &arbitrary_var));
DBUG_EXECUTE_IF("json_check_min_stack_requirement",
{alloca(my_thread_stack_size-stack_used_up-STACK_MIN_SIZE);});
{ALLOCATE_MEM_ON_STACK(my_thread_stack_size-stack_used_up-STACK_MIN_SIZE);});
if (check_stack_overrun(current_thd, STACK_MIN_SIZE , NULL))
return 1;
DBUG_EXECUTE_IF("json_check_min_stack_requirement",
{alloca(my_thread_stack_size-(STACK_MIN_SIZE));});
if (check_stack_overrun(current_thd, STACK_MIN_SIZE, NULL))
return 0;
switch (js->value_type)
{
case JSON_VALUE_OBJECT:
@ -2040,7 +2052,7 @@ static int do_merge(String *str, json_engine_t *je1, json_engine_t *je2)
long arbitrary_var;
long stack_used_up= (available_stack_size(current_thd->thread_stack, &arbitrary_var));
DBUG_EXECUTE_IF("json_check_min_stack_requirement",
{alloca(my_thread_stack_size-stack_used_up-STACK_MIN_SIZE);});
{ALLOCATE_MEM_ON_STACK(my_thread_stack_size-stack_used_up-STACK_MIN_SIZE);});
if (check_stack_overrun(current_thd, STACK_MIN_SIZE , NULL))
return 1;
@ -2379,7 +2391,7 @@ static int do_merge_patch(String *str, json_engine_t *je1, json_engine_t *je2,
long arbitrary_var;
long stack_used_up= (available_stack_size(current_thd->thread_stack, &arbitrary_var));
DBUG_EXECUTE_IF("json_check_min_stack_requirement",
{alloca(my_thread_stack_size-stack_used_up-STACK_MIN_SIZE);});
{ALLOCATE_MEM_ON_STACK(my_thread_stack_size-stack_used_up-STACK_MIN_SIZE);});
if (check_stack_overrun(current_thd, STACK_MIN_SIZE , NULL))
return 1;