Commit-ID: 51a16c1e887a5975ada27a3ae935a4f2783005da
Gitweb: http://git.kernel.org/tip/51a16c1e887a5975ada27a3ae935a4f2783005da
Author: John Stultz <john.stultz@xxxxxxxxxx>
AuthorDate: Wed, 17 Jun 2015 11:16:43 -0700
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 18 Jun 2015 15:28:14 +0200
selftest: Timers: Avoid signal deadlock in leap-a-day
In 0c4a5fc95b1df (Add leap-second timer edge testing to
leap-a-day.c), we added a timer to the test which checks to make
sure timers near the leapsecond edge behave correctly.
However, the output generated from the timer uses ctime_r, which
isn't async-signal safe, and should that signal land while the
main test is using ctime_r to print its output, its possible for
the test to deadlock on glibc internal locks.
Thus this patch reworks the output to avoid using ctime_r in
the signal handler.
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: Richard Cochran <richardcochran@xxxxxxxxx>
Cc: Jan Kara <jack@xxxxxxx>
Cc: Jiri Bohac <jbohac@xxxxxxx>
Cc: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1434565003-3386-1-git-send-email-john.stultz@xxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
---
tools/testing/selftests/timers/leap-a-day.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)
diff --git a/tools/testing/selftests/timers/leap-a-day.c b/tools/testing/selftests/timers/leap-a-day.c
index 331c4f7..fb46ad6 100644
--- a/tools/testing/selftests/timers/leap-a-day.c
+++ b/tools/testing/selftests/timers/leap-a-day.c
@@ -141,27 +141,28 @@ void handler(int unused)
void sigalarm(int signo)
{
struct timex tx;
- char buf[26];
int ret;
tx.modes = 0;
ret = adjtimex(&tx);
- ctime_r(&tx.time.tv_sec, buf);
- buf[strlen(buf)-1] = 0; /*remove trailing\n */
- printf("%s + %6ld us (%i)\t%s - TIMER FIRED\n",
- buf,
+ if (tx.time.tv_sec < next_leap) {
+ printf("Error: Early timer expiration! (Should be %ld)\n", next_leap);
+ error_found = 1;
+ printf("adjtimex: %10ld sec + %6ld us (%i)\t%s\n",
+ tx.time.tv_sec,
tx.time.tv_usec,
tx.tai,
time_state_str(ret));
-
- if (tx.time.tv_sec < next_leap) {
- printf("Error: Early timer expiration!\n");
- error_found = 1;
}
if (ret != TIME_WAIT) {
- printf("Error: Incorrect NTP state?\n");
+ printf("Error: Timer seeing incorrect NTP state? (Should be TIME_WAIT)\n");
error_found = 1;
+ printf("adjtimex: %10ld sec + %6ld us (%i)\t%s\n",
+ tx.time.tv_sec,
+ tx.time.tv_usec,
+ tx.tai,
+ time_state_str(ret));
}
}
@@ -297,7 +298,7 @@ int main(int argc, char **argv)
printf("Scheduling leap second for %s", ctime(&next_leap));
/* Set up timer */
- printf("Setting timer for %s", ctime(&next_leap));
+ printf("Setting timer for %ld - %s", next_leap, ctime(&next_leap));
memset(&se, 0, sizeof(se));
se.sigev_notify = SIGEV_SIGNAL;
se.sigev_signo = signum;
--
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