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Posted to commits@apr.apache.org by sf...@apache.org on 2014/05/14 22:41:31 UTC
svn commit: r1594707 - in /apr/apr/branches/1.6.x: ./ CHANGES configure.in
memory/unix/apr_pools.c
Author: sf
Date: Wed May 14 20:41:31 2014
New Revision: 1594707
URL: http://svn.apache.org/r1594707
Log:
Backport r1593614 from trunk:
Option to detect concurrent accesses to pools
Enabled by new configure option --enable-pool-concurrency-check.
Compared to pool-owner-debugging, this only detects cases where there is actual
contention between accesses. The advantage is that runtime costs should be
relatively low.
The diagnostic messages could still use some improvement.
Modified:
apr/apr/branches/1.6.x/ (props changed)
apr/apr/branches/1.6.x/CHANGES
apr/apr/branches/1.6.x/configure.in
apr/apr/branches/1.6.x/memory/unix/apr_pools.c
Propchange: apr/apr/branches/1.6.x/
------------------------------------------------------------------------------
Merged /apr/apr/trunk:r1593614
Modified: apr/apr/branches/1.6.x/CHANGES
URL: http://svn.apache.org/viewvc/apr/apr/branches/1.6.x/CHANGES?rev=1594707&r1=1594706&r2=1594707&view=diff
==============================================================================
--- apr/apr/branches/1.6.x/CHANGES [utf-8] (original)
+++ apr/apr/branches/1.6.x/CHANGES [utf-8] Wed May 14 20:41:31 2014
@@ -1,6 +1,10 @@
-*- coding: utf-8 -*-
Changes for APR 1.6.0
+ *) Add new --enable-pool-concurrency-check configure option to detect
+ thread-unsafe concurrent accesses to pools. Runtime costs should be
+ relatively low. [Stefan Fritsch]
+
*) Add support code to teach valgrind about APR pools and allocators.
[Stefan Fritsch]
Modified: apr/apr/branches/1.6.x/configure.in
URL: http://svn.apache.org/viewvc/apr/apr/branches/1.6.x/configure.in?rev=1594707&r1=1594706&r2=1594707&view=diff
==============================================================================
--- apr/apr/branches/1.6.x/configure.in (original)
+++ apr/apr/branches/1.6.x/configure.in Wed May 14 20:41:31 2014
@@ -1576,6 +1576,14 @@ AC_ARG_ENABLE(allocator-uses-mmap,
fi ]
)
+AC_ARG_ENABLE(pool-concurrency-check,
+ [ --enable-pool-concurrency-check Check for concurrent usage of memory pools],
+ [ if test "$enableval" = "yes"; then
+ AC_DEFINE(APR_POOL_CONCURRENCY_CHECK, 1,
+ [Define if pool functions should abort if concurrent usage is detected])
+ fi ]
+)
+
dnl ----------------------------- Checks for standard typedefs
AC_TYPE_OFF_T
AC_TYPE_PID_T
Modified: apr/apr/branches/1.6.x/memory/unix/apr_pools.c
URL: http://svn.apache.org/viewvc/apr/apr/branches/1.6.x/memory/unix/apr_pools.c?rev=1594707&r1=1594706&r2=1594707&view=diff
==============================================================================
--- apr/apr/branches/1.6.x/memory/unix/apr_pools.c (original)
+++ apr/apr/branches/1.6.x/memory/unix/apr_pools.c Wed May 14 20:41:31 2014
@@ -64,6 +64,11 @@ int apr_running_on_valgrind = 0;
#define APR_VALGRIND_UNDEFINED(addr_, size_) \
APR_IF_VALGRIND(VALGRIND_MAKE_MEM_UNDEFINED(addr_, size_))
+
+#if APR_POOL_CONCURRENCY_CHECK && !APR_HAS_THREADS
+#error pool-concurrency-check does not make sense without threads
+#endif
+
/*
* Magic numbers
*/
@@ -555,6 +560,10 @@ struct apr_pool_t {
apr_os_proc_t owner_proc;
#endif /* defined(NETWARE) */
cleanup_t *pre_cleanups;
+#if APR_POOL_CONCURRENCY_CHECK
+ volatile apr_uint32_t in_use;
+ apr_os_thread_t in_use_by;
+#endif /* APR_POOL_CONCURRENCY_CHECK */
};
#define SIZEOF_POOL_T APR_ALIGN_DEFAULT(sizeof(apr_pool_t))
@@ -688,6 +697,65 @@ APR_DECLARE(void) apr_pool_terminate(voi
#define node_free_space(node_) ((apr_size_t)(node_->endp - node_->first_avail))
/*
+ * Helpers to mark pool as in-use/free. Used for finding thread-unsafe
+ * concurrent accesses from different threads.
+ */
+#if APR_POOL_CONCURRENCY_CHECK
+static void pool_concurrency_abort(apr_pool_t *pool, const char *func, apr_uint32_t old)
+{
+ fprintf(stderr, "%s: previous state %d in_use_by/cur %lx/%lx pool %p(%s)\n",
+ func, old,
+ (unsigned long)pool->in_use_by,
+ (unsigned long)apr_os_thread_current(),
+ pool, pool->tag);
+ abort();
+}
+
+static APR_INLINE void pool_concurrency_set_used(apr_pool_t *pool)
+{
+ apr_uint32_t old;
+
+ old = apr_atomic_cas32(&pool->in_use, 1, 0);
+
+ if (old == 2 && pool->in_use_by == apr_os_thread_current()) {
+ /* cleanups may use the pool */
+ return;
+ }
+
+ if (old != 0)
+ pool_concurrency_abort(pool, __func__, old);
+
+ pool->in_use_by = apr_os_thread_current();
+}
+
+static APR_INLINE void pool_concurrency_set_idle(apr_pool_t *pool)
+{
+ apr_uint32_t old;
+
+ old = apr_atomic_cas32(&pool->in_use, 0, 1);
+
+ if (old != 1)
+ pool_concurrency_abort(pool, __func__, old);
+}
+
+static APR_INLINE void pool_concurrency_init(apr_pool_t *pool)
+{
+ pool->in_use = 0;
+}
+
+static APR_INLINE void pool_concurrency_set_destroyed(apr_pool_t *pool)
+{
+ apr_atomic_set32(&pool->in_use, 3);
+ pool->in_use_by = apr_os_thread_current();
+}
+#else
+static APR_INLINE void pool_concurrency_init(apr_pool_t *pool) { }
+static APR_INLINE void pool_concurrency_set_used(apr_pool_t *pool) { }
+static APR_INLINE void pool_concurrency_set_idle(apr_pool_t *pool) { }
+static APR_INLINE void pool_concurrency_set_destroyed(apr_pool_t *pool) { }
+#endif /* APR_POOL_CONCURRENCY_CHECK */
+
+/*
* Memory allocation
*/
@@ -697,12 +765,14 @@ APR_DECLARE(void *) apr_palloc(apr_pool_
void *mem;
apr_size_t size, free_index;
+ pool_concurrency_set_used(pool);
size = APR_ALIGN_DEFAULT(in_size);
#if HAVE_VALGRIND
if (apr_running_on_valgrind)
size += 2 * REDZONE;
#endif
if (size < in_size) {
+ pool_concurrency_set_idle(pool);
if (pool->abort_fn)
pool->abort_fn(APR_ENOMEM);
@@ -723,6 +793,7 @@ APR_DECLARE(void *) apr_palloc(apr_pool_
}
else {
if ((node = allocator_alloc(pool->allocator, size)) == NULL) {
+ pool_concurrency_set_idle(pool);
if (pool->abort_fn)
pool->abort_fn(APR_ENOMEM);
@@ -758,14 +829,17 @@ APR_DECLARE(void *) apr_palloc(apr_pool_
have_mem:
#if HAVE_VALGRIND
if (!apr_running_on_valgrind) {
+ pool_concurrency_set_idle(pool);
return mem;
}
else {
mem = (char *)mem + REDZONE;
VALGRIND_MEMPOOL_ALLOC(pool, mem, in_size);
+ pool_concurrency_set_idle(pool);
return mem;
}
#else
+ pool_concurrency_set_idle(pool);
return mem;
#endif
}
@@ -801,7 +875,10 @@ APR_DECLARE(void) apr_pool_clear(apr_poo
/* Run pre destroy cleanups */
run_cleanups(&pool->pre_cleanups);
+
+ pool_concurrency_set_used(pool);
pool->pre_cleanups = NULL;
+ pool_concurrency_set_idle(pool);
/* Destroy the subpools. The subpools will detach themselves from
* this pool thus this loop is safe and easy.
@@ -811,6 +888,8 @@ APR_DECLARE(void) apr_pool_clear(apr_poo
/* Run cleanups */
run_cleanups(&pool->cleanups);
+
+ pool_concurrency_set_used(pool);
pool->cleanups = NULL;
pool->free_cleanups = NULL;
@@ -829,13 +908,17 @@ APR_DECLARE(void) apr_pool_clear(apr_poo
APR_IF_VALGRIND(VALGRIND_MEMPOOL_TRIM(pool, pool, 1));
- if (active->next == active)
+ if (active->next == active) {
+ pool_concurrency_set_idle(pool);
return;
+ }
*active->ref = NULL;
allocator_free(pool->allocator, active->next);
active->next = active;
active->ref = &active->next;
+
+ pool_concurrency_set_idle(pool);
}
APR_DECLARE(void) apr_pool_destroy(apr_pool_t *pool)
@@ -845,7 +928,10 @@ APR_DECLARE(void) apr_pool_destroy(apr_p
/* Run pre destroy cleanups */
run_cleanups(&pool->pre_cleanups);
+
+ pool_concurrency_set_used(pool);
pool->pre_cleanups = NULL;
+ pool_concurrency_set_idle(pool);
/* Destroy the subpools. The subpools will detach themselve from
* this pool thus this loop is safe and easy.
@@ -855,6 +941,7 @@ APR_DECLARE(void) apr_pool_destroy(apr_p
/* Run cleanups */
run_cleanups(&pool->cleanups);
+ pool_concurrency_set_destroyed(pool);
/* Free subprocesses */
free_proc_chain(pool->subprocesses);
@@ -1000,6 +1087,8 @@ APR_DECLARE(apr_status_t) apr_pool_creat
pool->ref = NULL;
}
+ pool_concurrency_init(pool);
+
*newpool = pool;
return APR_SUCCESS;
@@ -1069,6 +1158,8 @@ APR_DECLARE(apr_status_t) apr_pool_creat
#endif /* defined(NETWARE) */
if (!allocator)
pool_allocator->owner = pool;
+
+ pool_concurrency_init(pool);
*newpool = pool;
return APR_SUCCESS;
@@ -1214,6 +1305,7 @@ APR_DECLARE(char *) apr_pvsprintf(apr_po
apr_memnode_t *active, *node;
apr_size_t free_index;
+ pool_concurrency_set_used(pool);
ps.node = active = pool->active;
ps.pool = pool;
ps.vbuff.curpos = ps.node->first_avail;
@@ -1276,8 +1368,10 @@ APR_DECLARE(char *) apr_pvsprintf(apr_po
/*
* Link the node in if it's a new one
*/
- if (!ps.got_a_new_node)
+ if (!ps.got_a_new_node) {
+ pool_concurrency_set_idle(pool);
return strp;
+ }
active = pool->active;
node = ps.node;
@@ -1294,8 +1388,10 @@ APR_DECLARE(char *) apr_pvsprintf(apr_po
active->free_index = (APR_UINT32_TRUNC_CAST)free_index;
node = active->next;
- if (free_index >= node->free_index)
+ if (free_index >= node->free_index) {
+ pool_concurrency_set_idle(pool);
return strp;
+ }
do {
node = node->next;
@@ -1305,9 +1401,11 @@ APR_DECLARE(char *) apr_pvsprintf(apr_po
list_remove(active);
list_insert(active, node);
+ pool_concurrency_set_idle(pool);
return strp;
error:
+ pool_concurrency_set_idle(pool);
if (pool->abort_fn)
pool->abort_fn(APR_ENOMEM);
if (ps.got_a_new_node) {