On Mon, Apr 4, 2011 at 9:26 PM, Paul Pluzhnikov <[email protected]> wrote:
> On Mon, Apr 4, 2011 at 9:01 PM, Arun Sharma <[email protected]> wrote:
>
>> Could you also add a test case to Ltest-nomalloc, so we catch any
>> mallocs in the fast unwind path? Thanks.
>
> That may not be easy: AFAICT glibc pthread_setspecific doesn't call
> calloc all the time; only when there are more than
> PTHREAD_KEY_2NDLEVEL_SIZE (== 32) keys, and even then only the first
> time for a block of keys.
>
> I'll try to make a test case anyway.
Attached patch makes a new Ltest-nocalloc test, and shows 1 calloc call
from Lassi's backtrace() on Ubuntu/glibc-2.11/x86_64 system:
FAILURE: detected 1 error (malloc: 0, calloc: 1)
Just as a sanity check, I ran it in GDB, and confirmed the expected
stack trace:
Breakpoint 2, calloc (n=32, s=16) at ../../tests/Gtest-nocalloc.c:60
60 if (in_unwind) {
(gdb) bt
#0 calloc (n=32, s=16) at ../../tests/Gtest-nocalloc.c:60
#1 0x00007ffff79c5ac9 in __pthread_setspecific (key=100,
value=0x7ffff7fb91f0) at pthread_setspecific.c:73
#2 0x00007ffff7fe4638 in trace_cache_get (cursor=0x7fffffffc6e0,
buffer=0x7fffffffd2d0, size=0x7fffffffd29c) at
../../src/x86_64/Gtrace.c:175
#3 _ULx86_64_tdep_trace (cursor=0x7fffffffc6e0, buffer=0x7fffffffd2d0,
size=0x7fffffffd29c) at ../../src/x86_64/Gtrace.c:424
#4 0x00007ffff7fe250e in unw_backtrace (buffer=0x7fffffffd2d0, size=100)
at ../../src/mi/backtrace.c:69
#5 0x0000000000400a28 in do_backtrace () at ../../tests/Gtest-nocalloc.c:91
#6 0x0000000000400b2d in foo3 (argc=<value optimized out>, argv=<value
optimized out>) at ../../tests/Gtest-nocalloc.c:98
#7 foo2 (argc=<value optimized out>, argv=<value optimized out>) at
../../tests/Gtest-nocalloc.c:104
#8 foo1 (argc=<value optimized out>, argv=<value optimized out>) at
../../tests/Gtest-nocalloc.c:110
#9 main (argc=<value optimized out>, argv=<value optimized out>) at
../../tests/Gtest-nocalloc.c:126
Now all we have to do is figure out how to fix it ;-)
Thanks,
--
Paul Pluzhnikov
diff --git a/tests/Gtest-nocalloc.c b/tests/Gtest-nocalloc.c
new file mode 100644
index 0000000..6f61b96
--- /dev/null
+++ b/tests/Gtest-nocalloc.c
@@ -0,0 +1,137 @@
+/* libunwind - a platform-independent unwind library
+ Copyright (C) 2011 Google, Inc
+ Contributed by Paul Pluzhnikov <[email protected]>
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
+
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+#include <execinfo.h> /* for backtrace */
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <dlfcn.h>
+#include <pthread.h>
+#include <libunwind.h>
+
+#define panic(args...) \
+ { fprintf (stderr, args); exit (-1); }
+
+int verbose;
+int num_mallocs;
+int num_callocs;
+int in_unwind;
+
+void *
+calloc(size_t n, size_t s)
+{
+ static void * (*func)();
+
+#ifdef __GLIBC__
+ /* In glibc, dlsym() calls calloc. Calling dlsym(RTLD_NEXT, "calloc") here
+ causes infinite recursion. Instead, we simply use it by its other
+ name. */
+ extern void *__libc_calloc();
+ func = &__libc_calloc;
+#else
+ if(!func)
+ func = (void *(*)()) dlsym(RTLD_NEXT, "calloc");
+#endif
+
+ if (in_unwind) {
+ num_callocs++;
+ return NULL;
+ } else {
+ return func(n, s);
+ }
+}
+
+void *
+malloc(size_t s)
+{
+ static void * (*func)();
+
+ if(!func)
+ func = (void *(*)()) dlsym(RTLD_NEXT, "malloc");
+
+ if (in_unwind) {
+ num_mallocs++;
+ return NULL;
+ } else {
+ return func(s);
+ }
+}
+
+static void
+do_backtrace (void)
+{
+ const int num_levels = 100;
+ void *pc[num_levels];
+
+ in_unwind = 1;
+ backtrace(pc, num_levels);
+ in_unwind = 0;
+}
+
+void
+foo3 ()
+{
+ do_backtrace ();
+}
+
+void
+foo2 ()
+{
+ foo3 ();
+}
+
+void
+foo1 (void)
+{
+ foo2 ();
+ return NULL;
+}
+
+int
+main (int argc, char **argv)
+{
+ int i, num_errors;
+
+ /* Create (and leak) 100 TSDs, then call backtrace()
+ and check that it doesn't call malloc()/calloc(). */
+ for (i = 0; i < 100; ++i) {
+ pthread_key_t key;
+ if (pthread_key_create (&key, NULL))
+ panic ("FAILURE: unable to create key %d\n", i);
+ }
+ foo1 ();
+ num_errors = num_mallocs + num_callocs;
+ if (num_errors > 0)
+ {
+ fprintf (stderr,
+ "FAILURE: detected %d error%s (malloc: %d, calloc: %d)\n",
+ num_errors, num_errors > 1 ? "s" : "",
+ num_mallocs, num_callocs);
+ exit (-1);
+ }
+ return 0;
+}
diff --git a/tests/Ltest-nocalloc.c b/tests/Ltest-nocalloc.c
new file mode 100644
index 0000000..8463dcf
--- /dev/null
+++ b/tests/Ltest-nocalloc.c
@@ -0,0 +1,5 @@
+#define UNW_LOCAL_ONLY
+#include <libunwind.h>
+#if !defined(UNW_REMOTE_ONLY)
+#include "Gtest-nocalloc.c"
+#endif
diff --git a/tests/Makefile.am b/tests/Makefile.am
index c724e43..d5e3ae2 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -1,7 +1,8 @@
AM_CPPFLAGS = -I$(top_srcdir)/include
EXTRA_DIST = run-ia64-test-dyn1 run-ptrace-mapper run-ptrace-misc \
- run-check-namespace check-namespace.sh.in Gtest-nomalloc.c
+ run-check-namespace check-namespace.sh.in Gtest-nomalloc.c \
+ Gtest-nocalloc.c
MAINTAINERCLEANFILES = Makefile.in
@@ -44,7 +45,7 @@ endif #ARCH_IA64
Gtest-trace Ltest-trace \
test-async-sig test-flush-cache test-init-remote \
test-mem test-setjmp test-ptrace \
- Ltest-nomalloc rs-race
+ Ltest-nomalloc Ltest-nocalloc rs-race
noinst_PROGRAMS_cdep = forker mapper test-ptrace-misc test-varargs \
Gperf-simple Lperf-simple \
Gperf-trace Lperf-trace
@@ -102,6 +103,7 @@ Gtest_bt_SOURCES = Gtest-bt.c ident.c
Ltest_bt_SOURCES = Ltest-bt.c ident.c
test_ptrace_misc_SOURCES = test-ptrace-misc.c ident.c
Ltest_nomalloc_SOURCES = Ltest-nomalloc.c
+Ltest_nocalloc_SOURCES = Ltest-nocalloc.c
Gtest_trace_SOURCES = Gtest-trace.c ident.c
Ltest_trace_SOURCES = Ltest-trace.c ident.c
@@ -148,6 +150,7 @@ Ltest_dyn1_LDADD = $(LIBUNWIND_local)
Ltest_exc_LDADD = $(LIBUNWIND_local)
Ltest_init_LDADD = $(LIBUNWIND_local)
Ltest_nomalloc_LDADD = $(LIBUNWIND_local) @DLLIB@
+Ltest_nocalloc_LDADD = $(LIBUNWIND_local) @DLLIB@ -lpthread
Ltest_resume_sig_LDADD = $(LIBUNWIND)
Lperf_simple_LDADD = $(LIBUNWIND_local)
Ltest_trace_LDADD = $(LIBUNWIND_local)
_______________________________________________
Libunwind-devel mailing list
[email protected]
http://lists.nongnu.org/mailman/listinfo/libunwind-devel
