The patch titled
Subject: watchdog: implement error handling in update_watchdog_all_cpus() and callers
has been added to the -mm tree. Its filename is
watchdog-implement-error-handling-in-update_watchdog_all_cpus-and-callers.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/watchdog-implement-error-handling-in-update_watchdog_all_cpus-and-callers.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/watchdog-implement-error-handling-in-update_watchdog_all_cpus-and-callers.patch
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------------------------------------------------------
From: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
Subject: watchdog: implement error handling in update_watchdog_all_cpus() and callers
update_watchdog_all_cpus() now passes errors from watchdog_park_threads()
up to functions in the call chain. This allows watchdog_enable_all_cpus()
and proc_watchdog_update() to handle such errors too.
Signed-off-by: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
Reviewed-by: Aaron Tomlin <atomlin@xxxxxxxxxx>
Cc: Don Zickus <dzickus@xxxxxxxxxx>
Cc: Ulrich Obergfell <uobergfe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/watchdog.c | 30 +++++++++++++++++++++++-------
1 file changed, 23 insertions(+), 7 deletions(-)
diff -puN kernel/watchdog.c~watchdog-implement-error-handling-in-update_watchdog_all_cpus-and-callers kernel/watchdog.c
--- a/kernel/watchdog.c~watchdog-implement-error-handling-in-update_watchdog_all_cpus-and-callers
+++ a/kernel/watchdog.c
@@ -731,10 +731,17 @@ void lockup_detector_resume(void)
mutex_unlock(&watchdog_proc_mutex);
}
-static void update_watchdog_all_cpus(void)
+static int update_watchdog_all_cpus(void)
{
- watchdog_park_threads();
+ int ret;
+
+ ret = watchdog_park_threads();
+ if (ret)
+ return ret;
+
watchdog_unpark_threads();
+
+ return 0;
}
static int watchdog_enable_all_cpus(void)
@@ -753,9 +760,17 @@ static int watchdog_enable_all_cpus(void
* Enable/disable the lockup detectors or
* change the sample period 'on the fly'.
*/
- update_watchdog_all_cpus();
+ err = update_watchdog_all_cpus();
+
+ if (err) {
+ watchdog_disable_all_cpus();
+ pr_err("Failed to update lockup detectors, disabled\n");
+ }
}
+ if (err)
+ watchdog_enabled = 0;
+
return err;
}
@@ -851,12 +866,13 @@ static int proc_watchdog_common(int whic
} while (cmpxchg(&watchdog_enabled, old, new) != old);
/*
- * Update the run state of the lockup detectors.
- * Restore 'watchdog_enabled' on failure.
+ * Update the run state of the lockup detectors. There is _no_
+ * need to check the value returned by proc_watchdog_update()
+ * and to restore the previous value of 'watchdog_enabled' as
+ * both lockup detectors are disabled if proc_watchdog_update()
+ * returns an error.
*/
err = proc_watchdog_update();
- if (err)
- watchdog_enabled = old;
}
out:
mutex_unlock(&watchdog_proc_mutex);
_
Patches currently in -mm which might be from uobergfe@xxxxxxxxxx are
watchdog-fix-error-handling-in-proc_watchdog_thresh.patch
watchdog-move-watchdog_disable_all_cpus-outside-of-ifdef.patch
watchdog-implement-error-handling-in-update_watchdog_all_cpus-and-callers.patch
watchdog-implement-error-handling-in-lockup_detector_suspend.patch
watchdog-do-not-unpark-threads-in-watchdog_park_threads-on-error.patch
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