From 4a170ee9e0ebd7021cb1190fabd5b0cbe2effb8e Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Fri, 4 Apr 2014 14:27:18 +0300
Subject: [PATCH] Add an Assertion that you don't palloc within a critical
section.
This caught a bunch of cases doing that already, which I just fixed in
previous commit. This is the assertion itself.
Per Tom Lane's idea.
---
src/backend/utils/mmgr/mcxt.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)
diff --git a/src/backend/utils/mmgr/mcxt.c b/src/backend/utils/mmgr/mcxt.c
index a7ca44dd86c..132b04d7c91 100644
--- a/src/backend/utils/mmgr/mcxt.c
+++ b/src/backend/utils/mmgr/mcxt.c
@@ -24,6 +24,7 @@
#include "postgres.h"
+#include "miscadmin.h"
#include "utils/memdebug.h"
#include "utils/memutils.h"
@@ -55,6 +56,19 @@ MemoryContext PortalContext = NULL;
static void MemoryContextStatsInternal(MemoryContext context, int level);
+/*
+ * You should not do memory allocations within a critical section, because
+ * an out-of-memory error will be escalated to a PANIC. To enforce that
+ * rule, the allocation functions Assert that.
+ *
+ * There are a two exceptions: 1) error recovery uses ErrorContext, which
+ * has some memory set aside so that you don't run out. And 2) checkpointer
+ * currently just hopes for the best, which is wrong and ought to be fixed,
+ * but it's a known issue so let's not complain about in the meanwhile.
+ */
+#define AssertNotInCriticalSection(context) \
+ Assert(CritSectionCount == 0 || (context) == ErrorContext || \
+ AmCheckpointerProcess())
/*****************************************************************************
* EXPORTED ROUTINES *
@@ -519,6 +533,8 @@ MemoryContextCreate(NodeTag tag, Size size,
MemoryContext node;
Size needed = size + strlen(name) + 1;
+ Assert(CritSectionCount == 0);
+
/* Get space for node and name */
if (TopMemoryContext != NULL)
{
@@ -575,6 +591,7 @@ MemoryContextAlloc(MemoryContext context, Size size)
void *ret;
AssertArg(MemoryContextIsValid(context));
+ AssertNotInCriticalSection(context);
if (!AllocSizeIsValid(size))
elog(ERROR, "invalid memory alloc request size %zu", size);
@@ -600,6 +617,7 @@ MemoryContextAllocZero(MemoryContext context, Size size)
void *ret;
AssertArg(MemoryContextIsValid(context));
+ AssertNotInCriticalSection(context);
if (!AllocSizeIsValid(size))
elog(ERROR, "invalid memory alloc request size %zu", size);
@@ -627,6 +645,7 @@ MemoryContextAllocZeroAligned(MemoryContext context, Size size)
void *ret;
AssertArg(MemoryContextIsValid(context));
+ AssertNotInCriticalSection(context);
if (!AllocSizeIsValid(size))
elog(ERROR, "invalid memory alloc request size %zu", size);
@@ -648,6 +667,7 @@ palloc(Size size)
void *ret;
AssertArg(MemoryContextIsValid(CurrentMemoryContext));
+ AssertNotInCriticalSection(CurrentMemoryContext);
if (!AllocSizeIsValid(size))
elog(ERROR, "invalid memory alloc request size %zu", size);
@@ -667,6 +687,7 @@ palloc0(Size size)
void *ret;
AssertArg(MemoryContextIsValid(CurrentMemoryContext));
+ AssertNotInCriticalSection(CurrentMemoryContext);
if (!AllocSizeIsValid(size))
elog(ERROR, "invalid memory alloc request size %zu", size);
@@ -738,6 +759,7 @@ repalloc(void *pointer, Size size)
((char *) pointer - STANDARDCHUNKHEADERSIZE))->context;
AssertArg(MemoryContextIsValid(context));
+ AssertNotInCriticalSection(context);
/* isReset must be false already */
Assert(!context->isReset);
@@ -760,6 +782,7 @@ MemoryContextAllocHuge(MemoryContext context, Size size)
void *ret;
AssertArg(MemoryContextIsValid(context));
+ AssertNotInCriticalSection(context);
if (!AllocHugeSizeIsValid(size))
elog(ERROR, "invalid memory alloc request size %zu", size);
@@ -801,6 +824,7 @@ repalloc_huge(void *pointer, Size size)
((char *) pointer - STANDARDCHUNKHEADERSIZE))->context;
AssertArg(MemoryContextIsValid(context));
+ AssertNotInCriticalSection(context);
/* isReset must be false already */
Assert(!context->isReset);
--
GitLab