Merge "liblog: resolve deadlocks"
diff --git a/include/log/log.h b/include/log/log.h
index 1cdf7bc..086d742 100644
--- a/include/log/log.h
+++ b/include/log/log.h
@@ -614,9 +614,11 @@
/*
* Use the per-tag properties "log.tag.<tagname>" to generate a runtime
- * result of non-zero to expose a log.
+ * result of non-zero to expose a log. prio is ANDROID_LOG_VERBOSE to
+ * ANDROID_LOG_FATAL. default_prio if no property. Undefined behavior if
+ * any other value.
*/
-int __android_log_is_loggable(int prio, const char *tag, int def);
+int __android_log_is_loggable(int prio, const char *tag, int default_prio);
int __android_log_error_write(int tag, const char *subTag, int32_t uid, const char *data,
uint32_t dataLen);
diff --git a/liblog/fake_log_device.c b/liblog/fake_log_device.c
index 8a8ece2..cb80ee6 100644
--- a/liblog/fake_log_device.c
+++ b/liblog/fake_log_device.c
@@ -99,6 +99,10 @@
static void lock()
{
+ /*
+ * If we trigger a signal handler in the middle of locked activity and the
+ * signal handler logs a message, we could get into a deadlock state.
+ */
pthread_mutex_lock(&fakeLogDeviceLock);
}
@@ -106,9 +110,12 @@
{
pthread_mutex_unlock(&fakeLogDeviceLock);
}
+
#else // !defined(_WIN32)
+
#define lock() ((void)0)
#define unlock() ((void)0)
+
#endif // !defined(_WIN32)
diff --git a/liblog/log_is_loggable.c b/liblog/log_is_loggable.c
index 814d96d..e128edb 100644
--- a/liblog/log_is_loggable.c
+++ b/liblog/log_is_loggable.c
@@ -23,6 +23,22 @@
#include <android/log.h>
+static pthread_mutex_t lock_loggable = PTHREAD_MUTEX_INITIALIZER;
+
+static void lock()
+{
+ /*
+ * If we trigger a signal handler in the middle of locked activity and the
+ * signal handler logs a message, we could get into a deadlock state.
+ */
+ pthread_mutex_lock(&lock_loggable);
+}
+
+static void unlock()
+{
+ pthread_mutex_unlock(&lock_loggable);
+}
+
struct cache {
const prop_info *pinfo;
uint32_t serial;
@@ -49,9 +65,7 @@
cache->c = buf[0];
}
-static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
-
-static int __android_log_level(const char *tag, int def)
+static int __android_log_level(const char *tag, int default_prio)
{
/* sizeof() is used on this array below */
static const char log_namespace[] = "persist.log.tag.";
@@ -86,7 +100,7 @@
strcpy(key, log_namespace);
- pthread_mutex_lock(&lock);
+ lock();
current_global_serial = __system_property_area_serial();
@@ -156,7 +170,7 @@
global_serial = current_global_serial;
- pthread_mutex_unlock(&lock);
+ unlock();
switch (toupper(c)) {
case 'V': return ANDROID_LOG_VERBOSE;
@@ -168,36 +182,47 @@
case 'A': return ANDROID_LOG_FATAL;
case 'S': return -1; /* ANDROID_LOG_SUPPRESS */
}
- return def;
+ return default_prio;
}
-int __android_log_is_loggable(int prio, const char *tag, int def)
+int __android_log_is_loggable(int prio, const char *tag, int default_prio)
{
- int logLevel = __android_log_level(tag, def);
+ int logLevel = __android_log_level(tag, default_prio);
return logLevel >= 0 && prio >= logLevel;
}
+/*
+ * Timestamp state generally remains constant, since a change is
+ * rare, we can accept a trylock failure gracefully. Use a separate
+ * lock from is_loggable to keep contention down b/25563384.
+ */
+static pthread_mutex_t lock_timestamp = PTHREAD_MUTEX_INITIALIZER;
+
char android_log_timestamp()
{
static struct cache r_time_cache = { NULL, -1, 0 };
static struct cache p_time_cache = { NULL, -1, 0 };
- static uint32_t serial;
- uint32_t current_serial;
char retval;
- pthread_mutex_lock(&lock);
+ if (pthread_mutex_trylock(&lock_timestamp)) {
+ /* We are willing to accept some race in this context */
+ if (!(retval = p_time_cache.c)) {
+ retval = r_time_cache.c;
+ }
+ } else {
+ static uint32_t serial;
+ uint32_t current_serial = __system_property_area_serial();
+ if (current_serial != serial) {
+ refresh_cache(&r_time_cache, "ro.logd.timestamp");
+ refresh_cache(&p_time_cache, "persist.logd.timestamp");
+ serial = current_serial;
+ }
+ if (!(retval = p_time_cache.c)) {
+ retval = r_time_cache.c;
+ }
- current_serial = __system_property_area_serial();
- if (current_serial != serial) {
- refresh_cache(&r_time_cache, "ro.logd.timestamp");
- refresh_cache(&p_time_cache, "persist.logd.timestamp");
- serial = current_serial;
+ pthread_mutex_unlock(&lock_timestamp);
}
- if (!(retval = p_time_cache.c)) {
- retval = r_time_cache.c;
- }
-
- pthread_mutex_unlock(&lock);
return tolower(retval ?: 'r');
}
diff --git a/liblog/logd_write.c b/liblog/logd_write.c
index a4310ae..83c6dc2 100644
--- a/liblog/logd_write.c
+++ b/liblog/logd_write.c
@@ -54,14 +54,35 @@
static int __write_to_log_init(log_id_t, struct iovec *vec, size_t nr);
static int (*write_to_log)(log_id_t, struct iovec *vec, size_t nr) = __write_to_log_init;
-#if !defined(_WIN32)
-static pthread_mutex_t log_init_lock = PTHREAD_MUTEX_INITIALIZER;
-#endif
#ifndef __unused
#define __unused __attribute__((__unused__))
#endif
+#if !defined(_WIN32)
+static pthread_mutex_t log_init_lock = PTHREAD_MUTEX_INITIALIZER;
+
+static void lock()
+{
+ /*
+ * If we trigger a signal handler in the middle of locked activity and the
+ * signal handler logs a message, we could get into a deadlock state.
+ */
+ pthread_mutex_lock(&log_init_lock);
+}
+
+static void unlock()
+{
+ pthread_mutex_unlock(&log_init_lock);
+}
+
+#else /* !defined(_WIN32) */
+
+#define lock() ((void)0)
+#define unlock() ((void)0)
+
+#endif /* !defined(_WIN32) */
+
#if FAKE_LOG_DEVICE
static int log_fds[(int)LOG_ID_MAX] = { -1, -1, -1, -1, -1 };
#else
@@ -277,15 +298,11 @@
if (ret < 0) {
ret = -errno;
if (ret == -ENOTCONN) {
-#if !defined(_WIN32)
- pthread_mutex_lock(&log_init_lock);
-#endif
+ lock();
close(logd_fd);
logd_fd = -1;
ret = __write_to_log_initialize();
-#if !defined(_WIN32)
- pthread_mutex_unlock(&log_init_lock);
-#endif
+ unlock();
if (ret < 0) {
return ret;
@@ -329,18 +346,14 @@
static int __write_to_log_init(log_id_t log_id, struct iovec *vec, size_t nr)
{
-#if !defined(_WIN32)
- pthread_mutex_lock(&log_init_lock);
-#endif
+ lock();
if (write_to_log == __write_to_log_init) {
int ret;
ret = __write_to_log_initialize();
if (ret < 0) {
-#if !defined(_WIN32)
- pthread_mutex_unlock(&log_init_lock);
-#endif
+ unlock();
#if (FAKE_LOG_DEVICE == 0)
if (pstore_fd >= 0) {
__write_to_log_daemon(log_id, vec, nr);
@@ -352,9 +365,7 @@
write_to_log = __write_to_log_daemon;
}
-#if !defined(_WIN32)
- pthread_mutex_unlock(&log_init_lock);
-#endif
+ unlock();
return write_to_log(log_id, vec, nr);
}
