2 * lock-tracer.c: Runtime simple lock tracer
5 * Rodrigo Kumpera (rkumpera@novell.com)
13 #include <sys/types.h>
19 #ifdef HAVE_EXECINFO_H
23 #include <mono/io-layer/io-layer.h>
25 #include "lock-tracer.h"
29 * This is a very simple lock trace implementation. It can be used to verify that the runtime is
30 * correctly following all locking rules.
32 * To log more kind of locks just do the following:
33 * - add an entry into the RuntimeLocks enum
34 * - change mono_mutex_lock(mutex) to mono_locks_acquire (mutex, LockName)
35 * - change mono_mutex_unlock to mono_locks_release (mutex, LockName)
36 * - change the decoder to understand the new lock kind.
39 * - Use unbuffered IO without fsync
40 * - Switch to a binary log format
41 * - Enable tracing of more runtime locks
42 * - Add lock check assertions (must_not_hold_any_lock_but, must_hold_lock, etc)
43 * This should be used to verify methods that expect that a given lock is held at entrypoint, for example.
45 * To use the trace, define LOCK_TRACER in lock-trace.h and when running mono define MONO_ENABLE_LOCK_TRACER.
46 * This will produce a locks.ZZZ where ZZZ is the pid of the mono process.
47 * Use the decoder to verify the result.
56 static FILE *trace_file;
57 static mono_mutex_t tracer_lock;
58 static size_t base_address;
61 RECORD_MUST_NOT_HOLD_ANY,
62 RECORD_MUST_NOT_HOLD_ONE,
69 mono_locks_tracer_init (void)
74 mono_mutex_init_recursive (&tracer_lock);
75 if (!g_getenv ("MONO_ENABLE_LOCK_TRACER"))
77 name = g_strdup_printf ("locks.%d", getpid ());
78 trace_file = fopen (name, "w+");
82 res = dladdr ((void*)&mono_locks_tracer_init, &info);
83 /* The 0x1000 offset was found by empirically trying it. */
85 base_address = (size_t)info.dli_fbase - 0x1000;
90 #ifdef HAVE_EXECINFO_H
93 mono_backtrace (gpointer array[], int traces)
95 return backtrace (array, traces);
101 mono_backtrace (gpointer array[], int traces)
109 add_record (RecordType record_kind, RuntimeLocks kind, gpointer lock)
112 const int no_frames = 6;
113 gpointer frames[no_frames];
119 memset (frames, 0, sizeof (gpointer) * no_frames);
120 mono_backtrace (frames, no_frames);
121 for (i = 0; i < no_frames; ++i)
122 frames [i] = (gpointer)((size_t)frames[i] - base_address);
124 /*We only dump 5 frames, which should be more than enough to most analysis.*/
125 msg = g_strdup_printf ("%x,%d,%d,%p,%p,%p,%p,%p,%p\n", (guint32)mono_native_thread_id_get (), record_kind, kind, lock, frames [1], frames [2], frames [3], frames [4], frames [5]);
126 fwrite (msg, strlen (msg), 1, trace_file);
132 mono_locks_lock_acquired (RuntimeLocks kind, gpointer lock)
134 add_record (RECORD_LOCK_ACQUIRED, kind, lock);
138 mono_locks_lock_released (RuntimeLocks kind, gpointer lock)
140 add_record (RECORD_LOCK_RELEASED, kind, lock);