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Add support for detecting register-stack overrun on IA64.

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Per recent investigation, the register stack can grow faster than the
regular stack depending on compiler and choice of options.  To avoid
crashes we must check both stacks in check_stack_depth().

Back-patch to all supported versions.
This commit is contained in:
Tom Lane 2010-11-06 22:59:15 -04:00
parent 78f0924f00
commit faa9007983
1 changed files with 60 additions and 0 deletions
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60
src/backend/tcop/postgres.c
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@ -111,6 +111,12 @@ static long max_stack_depth_bytes = 100 * 1024L;
*/
char *stack_base_ptr = NULL;
/*
* On IA64 we also have to remember the register stack base.
*/
#if defined(__ia64__) || defined(__ia64)
char *register_stack_base_ptr = NULL;
#endif
/*
* Flag to mark SIGHUP. Whenever the main loop comes around it
@ -2677,6 +2683,35 @@ ProcessInterrupts(void)
}
/*
* IA64-specific code to fetch the AR.BSP register for stack depth checks.
*
* We currently support gcc and icc here.
*/
#if defined(__ia64__) || defined(__ia64)
#include <asm/ia64regs.h>
static __inline__ char *
ia64_get_bsp(void)
{
char *ret;
#ifndef __INTEL_COMPILER
/* the ;; is a "stop", seems to be required before fetching BSP */
__asm__ __volatile__(
";;\n"
" mov %0=ar.bsp \n"
: "=r"(ret));
#else
ret = (char *) __getReg(_IA64_REG_AR_BSP);
#endif
return ret;
}
#endif /* IA64 */
/*
* check_stack_depth: check for excessively deep recursion
*
@ -2719,6 +2754,28 @@ check_stack_depth(void)
errhint("Increase the configuration parameter \"max_stack_depth\", "
"after ensuring the platform's stack depth limit is adequate.")));
}
/*
* On IA64 there is a separate "register" stack that requires its own
* independent check. For this, we have to measure the change in the
* "BSP" pointer from PostgresMain to here. Logic is just as above,
* except that we know IA64's register stack grows up.
*
* Note we assume that the same max_stack_depth applies to both stacks.
*/
#if defined(__ia64__) || defined(__ia64)
stack_depth = (long) (ia64_get_bsp() - register_stack_base_ptr);
if (stack_depth > max_stack_depth_bytes &&
register_stack_base_ptr != NULL)
{
ereport(ERROR,
(errcode(ERRCODE_STATEMENT_TOO_COMPLEX),
errmsg("stack depth limit exceeded"),
errhint("Increase the configuration parameter \"max_stack_depth\", "
"after ensuring the platform's stack depth limit is adequate.")));
}
#endif /* IA64 */
}
/* GUC assign hook for max_stack_depth */
@ -2894,6 +2951,9 @@ PostgresMain(int argc, char *argv[], const char *username)
/* Set up reference point for stack depth checking */
stack_base_ptr = &stack_base;
#if defined(__ia64__) || defined(__ia64)
register_stack_base_ptr = ia64_get_bsp();
#endif
/* Compute paths, if we didn't inherit them from postmaster */
if (my_exec_path[0] == '\0')