From 17105a0ad9e0678897a5c63cf581bde8daca049d Mon Sep 17 00:00:00 2001
From: marko <>
Date: Mon, 29 Jun 2009 08:24:27 +0000
Subject: [PATCH] branches/zip: buf_page_get_gen(): Fix a race condition when
reading buf_fix_count. This could explain Issue #156. Tested by Michael.
---
ChangeLog | 7 +++++++
buf/buf0buf.c | 4 ++++
2 files changed, 11 insertions(+)
diff --git a/ChangeLog b/ChangeLog
index 90bb25210f2..a1ab798bec7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2009-06-29 The InnoDB Team
+
+ * buf/buf0buf.c:
+ Fix a race condition when reading buf_fix_count.
+ Currently, it is not being protected by the buffer pool mutex,
+ but by the block mutex.
+
2009-06-29 The InnoDB Team
* handler/handler0alter.cc:
diff --git a/buf/buf0buf.c b/buf/buf0buf.c
index 24b3c933e8c..e973002ed5c 100644
--- a/buf/buf0buf.c
+++ b/buf/buf0buf.c
@@ -2085,12 +2085,15 @@ loop2:
case BUF_BLOCK_ZIP_PAGE:
case BUF_BLOCK_ZIP_DIRTY:
bpage = &block->page;
+ /* Protect bpage->buf_fix_count. */
+ mutex_enter(&buf_pool_zip_mutex);
if (bpage->buf_fix_count
|| buf_page_get_io_fix(bpage) != BUF_IO_NONE) {
/* This condition often occurs when the buffer
is not buffer-fixed, but I/O-fixed by
buf_page_init_for_read(). */
+ mutex_exit(&buf_pool_zip_mutex);
wait_until_unfixed:
/* The block is buffer-fixed or I/O-fixed.
Try again later. */
@@ -2102,6 +2105,7 @@ wait_until_unfixed:
/* Allocate an uncompressed page. */
buf_pool_mutex_exit();
+ mutex_exit(&buf_pool_zip_mutex);
block = buf_LRU_get_free_block(0);
ut_a(block);