Show errors from getSchedulerGroup().
If we failed to get the cgroup info, we were showing "unknown" in the
stack trace, and sometimes showing an error message in the log file.
Now we put a very brief error description into the cgroup text field,
so it shows up in the stack trace itself.
Also, replaced three strsep() calls with two strchr() calls.
Also, check return value from pthread_kill() calls.
Bug 3032532.
Change-Id: I3730cfb8a5c59048d35d746d8bffb4fa61bd5a6c
diff --git a/vm/Thread.c b/vm/Thread.c
index f27cc75..6a5ab1a 100644
--- a/vm/Thread.c
+++ b/vm/Thread.c
@@ -3397,11 +3397,12 @@
* 2:cpu:/bg_non_interactive
* 1:cpuacct:/
*
- * We return the part after the "/", which will be an empty string for
- * the default cgroup. If the string is longer than "bufLen", the string
- * will be truncated.
+ * We return the part on the "cpu" line after the '/', which will be an
+ * empty string for the default cgroup. If the string is longer than
+ * "bufLen", the string will be truncated.
*
- * TODO: this is cloned from a static function in libcutils; expose that?
+ * On error, -1 is returned, and an error description will be stored in
+ * the buffer.
*/
static int getSchedulerGroup(int tid, char* buf, size_t bufLen)
{
@@ -3411,34 +3412,33 @@
FILE *fp;
snprintf(pathBuf, sizeof(pathBuf), "/proc/%d/cgroup", tid);
- if (!(fp = fopen(pathBuf, "r"))) {
+ if ((fp = fopen(pathBuf, "r")) == NULL) {
+ snprintf(buf, bufLen, "[fopen-error:%d]", errno);
return -1;
}
- while(fgets(lineBuf, sizeof(lineBuf) -1, fp)) {
- char *next = lineBuf;
- char *subsys;
- char *grp;
+ while (fgets(lineBuf, sizeof(lineBuf) -1, fp) != NULL) {
+ char* subsys;
+ char* grp;
size_t len;
/* Junk the first field */
- if (!strsep(&next, ":")) {
+ subsys = strchr(lineBuf, ':');
+ if (subsys == NULL) {
goto out_bad_data;
}
- if (!(subsys = strsep(&next, ":"))) {
- goto out_bad_data;
- }
-
- if (strcmp(subsys, "cpu")) {
+ if (strncmp(subsys, ":cpu:", 5) != 0) {
/* Not the subsys we're looking for */
continue;
}
- if (!(grp = strsep(&next, ":"))) {
+ grp = strchr(subsys, '/');
+ if (grp == NULL) {
goto out_bad_data;
}
grp++; /* Drop the leading '/' */
+
len = strlen(grp);
grp[len-1] = '\0'; /* Drop the trailing '\n' */
@@ -3451,15 +3451,18 @@
return 0;
}
- LOGE("Failed to find cpu subsys");
+ snprintf(buf, bufLen, "[no-cpu-subsys]");
fclose(fp);
return -1;
- out_bad_data:
+
+out_bad_data:
LOGE("Bad cgroup data {%s}", lineBuf);
+ snprintf(buf, bufLen, "[data-parse-failed]");
fclose(fp);
return -1;
+
#else
- errno = ENOSYS;
+ snprintf(buf, bufLen, "[n/a]");
return -1;
#endif
}
@@ -3538,10 +3541,8 @@
sp.sched_priority = -1;
}
if (getSchedulerGroup(thread->systemTid, schedulerGroupBuf,
- sizeof(schedulerGroupBuf)) != 0)
- {
- strcpy(schedulerGroupBuf, "unknown");
- } else if (schedulerGroupBuf[0] == '\0') {
+ sizeof(schedulerGroupBuf)) == 0 &&
+ schedulerGroupBuf[0] == '\0') {
strcpy(schedulerGroupBuf, "default");
}
@@ -3717,6 +3718,8 @@
*/
void dvmNukeThread(Thread* thread)
{
+ int killResult;
+
/* suppress the heapworker watchdog to assist anyone using a debugger */
gDvm.nativeDebuggerActive = true;
@@ -3739,9 +3742,15 @@
LOGD("threadid=%d: sending two SIGSTKFLTs to threadid=%d (tid=%d) to"
" cause debuggerd dump\n",
dvmThreadSelf()->threadId, thread->threadId, thread->systemTid);
- pthread_kill(thread->handle, SIGSTKFLT);
+ killResult = pthread_kill(thread->handle, SIGSTKFLT);
+ if (killResult != 0) {
+ LOGD("NOTE: pthread_kill #1 failed: %s\n", strerror(killResult));
+ }
usleep(2 * 1000 * 1000); // TODO: timed-wait until debuggerd attaches
- pthread_kill(thread->handle, SIGSTKFLT);
+ killResult = pthread_kill(thread->handle, SIGSTKFLT);
+ if (killResult != 0) {
+ LOGD("NOTE: pthread_kill #2 failed: %s\n", strerror(killResult));
+ }
LOGD("Sent, pausing to let debuggerd run\n");
usleep(8 * 1000 * 1000); // TODO: timed-wait until debuggerd finishes
