Subject: Avoid segfault of cyclictest if it gets immediately interrupted.
From: Daniel Gollub <dgollub@xxxxxxx>
If clock_nanosleep() gets interrupted this could result in a negative
time diff from calcdiff().
With the histogram patch this leads to a segfault, since the time diff
is used as index for the histogram array:
Core was generated by `/usr/bin/cyclictest -n -q -p 99 -t 2 -i 500 -l
1000000 -h
20000'.
Program terminated with signal 11, Segmentation fault.
#0 0x0000000000402324 in timerthread (param=<value optimized out>)
at src/cyclictest/cyclictest.c:339
339 stat->hist_array[diff] += 1;
(gdb) p diff
$1 = -751974
Signed-off-by: Daniel Gollub <dgollub@xxxxxxx>
Acked-by: Sven-Thorsten Dietrich <sdietrich@xxxxxxx>
---
src/cyclictest/cyclictest.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)
Index: rt-tests/src/cyclictest/cyclictest.c
===================================================================
--- rt-tests.orig/src/cyclictest/cyclictest.c
+++ rt-tests/src/cyclictest/cyclictest.c
@@ -376,7 +376,7 @@ void *timerthread(void *param)
while (!shutdown) {
long diff;
- int sigs;
+ int sigs, ret;
/* Wait for next period */
switch (par->mode) {
@@ -387,17 +387,24 @@ void *timerthread(void *param)
break;
case MODE_CLOCK_NANOSLEEP:
- if (par->timermode == TIMER_ABSTIME)
- clock_nanosleep(par->clock, TIMER_ABSTIME,
+ if (par->timermode == TIMER_ABSTIME) {
+ ret = clock_nanosleep(par->clock, TIMER_ABSTIME,
&next, NULL);
- else {
+ } else {
clock_gettime(par->clock, &now);
- clock_nanosleep(par->clock, TIMER_RELTIME,
+ ret = clock_nanosleep(par->clock, TIMER_RELTIME,
&interval, NULL);
next.tv_sec = now.tv_sec + interval.tv_sec;
next.tv_nsec = now.tv_nsec + interval.tv_nsec;
tsnorm(&next);
}
+
+ /* Avoid negative calcdiff result if clock_nanosleep()
+ * gets interrupted.
+ */
+ if (ret == EINTR)
+ goto out;
+
break;
case MODE_SYS_NANOSLEEP:
--
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