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MDEV-9733 Server crashes in lf_pinbox_real_free on replication slaves
don't allocate all the stack, leave some stack for
function calls.

To test I added the following line:
  alloca_size = available_stack_size() - X
at X=4096 or less mysqld crashed, at 8192 mtr test passed.
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vuvova committed Mar 17, 2016
1 parent 0b9fb9a commit fc2c1e4
Showing 1 changed file with 8 additions and 1 deletion.
9 changes: 8 additions & 1 deletion mysys/lf_alloc-pin.c
Expand Up @@ -103,6 +103,12 @@
#include <my_sys.h>
#include <lf.h>

/*
when using alloca() leave at least that many bytes of the stack -
for functions we might be calling from within this stack frame
*/
#define ALLOCA_SAFETY_MARGIN 8192

#define LF_PINBOX_MAX_PINS 65536

static void _lf_pinbox_real_free(LF_PINS *pins);
Expand Down Expand Up @@ -349,7 +355,8 @@ static void _lf_pinbox_real_free(LF_PINS *pins)
{
int alloca_size= sizeof(void *)*LF_PINBOX_PINS*npins;
/* create a sorted list of pinned addresses, to speed up searches */
if (available_stack_size(&pinbox, *pins->stack_ends_here) > alloca_size)
if (available_stack_size(&pinbox, *pins->stack_ends_here) >
alloca_size + ALLOCA_SAFETY_MARGIN)
{
struct st_harvester hv;
addr= (void **) alloca(alloca_size);
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