On Fri, Apr 3, 2015 at 6:35 PM, Fujii Masao wrote:
> Regarding the second patch, you added the checks of the return value of
> XLogReaderAllocate(). But it seems half-baked. XLogReaderAllocate() still
> uses palloc(), but don't we need to replace it with palloc_extended(), too?
Doh, you are right. I missed three places. Attached is a new patch
completing the fix.
--
Michael
From 292012c19805777cf17443eccd9b4ef05c5f42ec Mon Sep 17 00:00:00 2001
From: Michael Paquier <mich...@otacoo.com>
Date: Fri, 3 Apr 2015 20:29:39 +0900
Subject: [PATCH] Fix error handling of XLogReaderAllocate in case of OOM
Similarly to previous fix 9b8d478, commit 2c03216 has switched
XLogReaderAllocate() to use a set of palloc calls instead of malloc,
causing any callers of this function to fail with an error instead of
receiving a NULL pointer in case of out-of-memory error. Fix this by
using palloc_extended with MCXT_ALLOC_NO_OOM that will safely return
NULL in case of an OOM, making this routine compatible with previous
major versions.
---
src/backend/access/transam/xlogreader.c | 23 ++++++++++++++++++++---
src/backend/replication/logical/logical.c | 5 +++++
src/bin/pg_rewind/parsexlog.c | 6 ++++++
3 files changed, 31 insertions(+), 3 deletions(-)
diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c
index ffdc975..9047805 100644
--- a/src/backend/access/transam/xlogreader.c
+++ b/src/backend/access/transam/xlogreader.c
@@ -66,7 +66,11 @@ XLogReaderAllocate(XLogPageReadCB pagereadfunc, void *private_data)
{
XLogReaderState *state;
- state = (XLogReaderState *) palloc0(sizeof(XLogReaderState));
+ state = (XLogReaderState *)
+ palloc_extended(sizeof(XLogReaderState),
+ MCXT_ALLOC_NO_OOM | MCXT_ALLOC_ZERO);
+ if (!state)
+ return NULL;
state->max_block_id = -1;
@@ -77,14 +81,27 @@ XLogReaderAllocate(XLogPageReadCB pagereadfunc, void *private_data)
* isn't guaranteed to have any particular alignment, whereas palloc()
* will provide MAXALIGN'd storage.
*/
- state->readBuf = (char *) palloc(XLOG_BLCKSZ);
+ state->readBuf = (char *) palloc_extended(XLOG_BLCKSZ,
+ MCXT_ALLOC_NO_OOM);
+ if (!state->readBuf)
+ {
+ pfree(state);
+ return NULL;
+ }
state->read_page = pagereadfunc;
/* system_identifier initialized to zeroes above */
state->private_data = private_data;
/* ReadRecPtr and EndRecPtr initialized to zeroes above */
/* readSegNo, readOff, readLen, readPageTLI initialized to zeroes above */
- state->errormsg_buf = palloc(MAX_ERRORMSG_LEN + 1);
+ state->errormsg_buf = palloc_extended(MAX_ERRORMSG_LEN + 1,
+ MCXT_ALLOC_NO_OOM);
+ if (!state->errormsg_buf)
+ {
+ pfree(state->readBuf);
+ pfree(state);
+ return NULL;
+ }
state->errormsg_buf[0] = '\0';
/*
diff --git a/src/backend/replication/logical/logical.c b/src/backend/replication/logical/logical.c
index 30baa45..774ebbc 100644
--- a/src/backend/replication/logical/logical.c
+++ b/src/backend/replication/logical/logical.c
@@ -163,6 +163,11 @@ StartupDecodingContext(List *output_plugin_options,
ctx->slot = slot;
ctx->reader = XLogReaderAllocate(read_page, ctx);
+ if (!ctx->reader)
+ ereport(ERROR,
+ (errcode(ERRCODE_OUT_OF_MEMORY),
+ errmsg("out of memory")));
+
ctx->reader->private_data = ctx;
ctx->reorder = ReorderBufferAllocate();
diff --git a/src/bin/pg_rewind/parsexlog.c b/src/bin/pg_rewind/parsexlog.c
index 0787ca1..3cf96ab 100644
--- a/src/bin/pg_rewind/parsexlog.c
+++ b/src/bin/pg_rewind/parsexlog.c
@@ -70,6 +70,8 @@ extractPageMap(const char *datadir, XLogRecPtr startpoint, TimeLineID tli,
private.datadir = datadir;
private.tli = tli;
xlogreader = XLogReaderAllocate(&SimpleXLogPageRead, &private);
+ if (xlogreader == NULL)
+ pg_fatal("out of memory");
do
{
@@ -121,6 +123,8 @@ readOneRecord(const char *datadir, XLogRecPtr ptr, TimeLineID tli)
private.datadir = datadir;
private.tli = tli;
xlogreader = XLogReaderAllocate(&SimpleXLogPageRead, &private);
+ if (xlogreader == NULL)
+ pg_fatal("out of memory");
record = XLogReadRecord(xlogreader, ptr, &errormsg);
if (record == NULL)
@@ -171,6 +175,8 @@ findLastCheckpoint(const char *datadir, XLogRecPtr forkptr, TimeLineID tli,
private.datadir = datadir;
private.tli = tli;
xlogreader = XLogReaderAllocate(&SimpleXLogPageRead, &private);
+ if (xlogreader == NULL)
+ pg_fatal("out of memory");
searchptr = forkptr;
for (;;)
--
2.3.5
--
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