mariadb/unittest/mysys/lf-t.c
Marc Alff d343f5e372 Bug#12552516 LF_HASH REQUIRES MY_THREAD_INIT()
Before this fix, a thread instrumented for the performance schema,
that would perform file io operations, could crash inside the LF_HASH
implementation, in cases when my_thread_init is not called.

The crash itself has not been reported in 5.5 but similar crashes have
been found in 5.6-based development branches, using LF_HASH for
more instrumentation.

The possibility of a crash in 5.5 is confirmed by code analysis.

The problem is that, when my_thread_init() is not called,
which can happen for threads in storage engines or thirs party code,
my_thread_var is NULL.

Using my_thread_var->stacks_ends_here in mysys/lf_alloc-pin.c is unsafe.

Given that my_thread_var is used:
- only for stacks_ends_here
- only on platform with HAVE_ALLOCA
- only when there is enough room on the stack
and given that the LF_HASH implementation has a fallback
algorythm implemented already when using alloca is not possible,
using my_thread_var->stacks_ends_here is in fact not a strict requirement,
and can be relaxed.

The fix is to:
- test explicitly if my_thread_var is NULL, to account for cases
  when my_thread_init() is not used by the calling thread.
- not use alloca in this case, and rely on the fall back code already in place.
  so that the LF_HASH can be supported even without my_thread_init().

The implementation of mysys/lf_alloc-pin.c has been fixed to support this new usage.
The units tests in unittest/mysys/lf-t.c have been adjusted accordingly.
2011-05-13 18:04:49 +02:00

195 lines
4.8 KiB
C

/* Copyright (C) 2008-2008 MySQL AB, 2008-2009 Sun Microsystems, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
/**
@file
Unit tests for lock-free algorithms of mysys
*/
#include "thr_template.c"
#include <lf.h>
int32 inserts= 0, N;
LF_ALLOCATOR lf_allocator;
LF_HASH lf_hash;
int with_my_thread_init=0;
/*
pin allocator - alloc and release an element in a loop
*/
pthread_handler_t test_lf_pinbox(void *arg)
{
int m= *(int *)arg;
int32 x= 0;
LF_PINS *pins;
if (with_my_thread_init)
my_thread_init();
pins= lf_pinbox_get_pins(&lf_allocator.pinbox);
for (x= ((int)(intptr)(&m)); m ; m--)
{
lf_pinbox_put_pins(pins);
pins= lf_pinbox_get_pins(&lf_allocator.pinbox);
}
lf_pinbox_put_pins(pins);
pthread_mutex_lock(&mutex);
if (!--running_threads) pthread_cond_signal(&cond);
pthread_mutex_unlock(&mutex);
if (with_my_thread_init)
my_thread_end();
return 0;
}
/*
thread local data area, allocated using lf_alloc.
union is required to enforce the minimum required element size (sizeof(ptr))
*/
typedef union {
int32 data;
void *not_used;
} TLA;
pthread_handler_t test_lf_alloc(void *arg)
{
int m= (*(int *)arg)/2;
int32 x,y= 0;
LF_PINS *pins;
if (with_my_thread_init)
my_thread_init();
pins= lf_alloc_get_pins(&lf_allocator);
for (x= ((int)(intptr)(&m)); m ; m--)
{
TLA *node1, *node2;
x= (x*m+0x87654321) & INT_MAX32;
node1= (TLA *)lf_alloc_new(pins);
node1->data= x;
y+= node1->data;
node1->data= 0;
node2= (TLA *)lf_alloc_new(pins);
node2->data= x;
y-= node2->data;
node2->data= 0;
lf_alloc_free(pins, node1);
lf_alloc_free(pins, node2);
}
lf_alloc_put_pins(pins);
pthread_mutex_lock(&mutex);
bad+= y;
if (--N == 0)
{
diag("%d mallocs, %d pins in stack",
lf_allocator.mallocs, lf_allocator.pinbox.pins_in_array);
#ifdef MY_LF_EXTRA_DEBUG
bad|= lf_allocator.mallocs - lf_alloc_pool_count(&lf_allocator);
#endif
}
if (!--running_threads) pthread_cond_signal(&cond);
pthread_mutex_unlock(&mutex);
if (with_my_thread_init)
my_thread_end();
return 0;
}
#define N_TLH 1000
pthread_handler_t test_lf_hash(void *arg)
{
int m= (*(int *)arg)/(2*N_TLH);
int32 x,y,z,sum= 0, ins= 0;
LF_PINS *pins;
if (with_my_thread_init)
my_thread_init();
pins= lf_hash_get_pins(&lf_hash);
for (x= ((int)(intptr)(&m)); m ; m--)
{
int i;
y= x;
for (i= 0; i < N_TLH; i++)
{
x= (x*(m+i)+0x87654321) & INT_MAX32;
z= (x<0) ? -x : x;
if (lf_hash_insert(&lf_hash, pins, &z))
{
sum+= z;
ins++;
}
}
for (i= 0; i < N_TLH; i++)
{
y= (y*(m+i)+0x87654321) & INT_MAX32;
z= (y<0) ? -y : y;
if (lf_hash_delete(&lf_hash, pins, (uchar *)&z, sizeof(z)))
sum-= z;
}
}
lf_hash_put_pins(pins);
pthread_mutex_lock(&mutex);
bad+= sum;
inserts+= ins;
if (--N == 0)
{
diag("%d mallocs, %d pins in stack, %d hash size, %d inserts",
lf_hash.alloc.mallocs, lf_hash.alloc.pinbox.pins_in_array,
lf_hash.size, inserts);
bad|= lf_hash.count;
}
if (!--running_threads) pthread_cond_signal(&cond);
pthread_mutex_unlock(&mutex);
if (with_my_thread_init)
my_thread_end();
return 0;
}
void do_tests()
{
plan(7);
lf_alloc_init(&lf_allocator, sizeof(TLA), offsetof(TLA, not_used));
lf_hash_init(&lf_hash, sizeof(int), LF_HASH_UNIQUE, 0, sizeof(int), 0,
&my_charset_bin);
bad= my_atomic_initialize();
ok(!bad, "my_atomic_initialize() returned %d", bad);
with_my_thread_init= 1;
test_concurrently("lf_pinbox (with my_thread_init)", test_lf_pinbox, N= THREADS, CYCLES);
test_concurrently("lf_alloc (with my_thread_init)", test_lf_alloc, N= THREADS, CYCLES);
test_concurrently("lf_hash (with my_thread_init)", test_lf_hash, N= THREADS, CYCLES/10);
with_my_thread_init= 0;
test_concurrently("lf_pinbox (without my_thread_init)", test_lf_pinbox, N= THREADS, CYCLES);
test_concurrently("lf_alloc (without my_thread_init)", test_lf_alloc, N= THREADS, CYCLES);
test_concurrently("lf_hash (without my_thread_init)", test_lf_hash, N= THREADS, CYCLES/10);
lf_hash_destroy(&lf_hash);
lf_alloc_destroy(&lf_allocator);
}