As sysctl_hung_task_timeout_sec is unsigned long, when this value is larger then LONG_MAX, the function schedule_timeout_interruptible in watchdog will return immediately without sleep :
for example (in x86_64 platform): linux# echo 0xFFFFFFFFFFFFFFFF > /proc/sys/kernel/hung_task_timeout_secs [ 66.798350] schedule_timeout: wrong timeout value ffffffffffffff06 [ 66.800064] schedule_timeout: wrong timeout value ffffffffffffff06 [ 66.801774] schedule_timeout: wrong timeout value ffffffffffffff06 [ 66.803488] schedule_timeout: wrong timeout value ffffffffffffff06 [ 66.805225] schedule_timeout: wrong timeout value ffffffffffffff06 The screen was filled with "schedule_timeout: wrong timeout value ffffffffffffff06" and the system stalled. So I do some check and correction in timeout_jiffies, to let the function schedule_timeout_interruptible allways get the valid parameter. Signed-off-by: Liu Hua <[email protected]> --- kernel/hung_task.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/kernel/hung_task.c b/kernel/hung_task.c index 06bb141..ef96650 100644 --- a/kernel/hung_task.c +++ b/kernel/hung_task.c @@ -186,7 +186,16 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout) static unsigned long timeout_jiffies(unsigned long timeout) { /* timeout of 0 will disable the watchdog */ - return timeout ? timeout * HZ : MAX_SCHEDULE_TIMEOUT; + if ((timeout == 0) || (timeout > MAX_SCHEDULE_TIMEOUT)) { + pr_err("%s : wrong timeout value %lx\n", + __func__, timeout); + pr_err("Timeout value is set to MAX_SCHEDULE_TIMEOUT(%lx) now.\n", + MAX_SCHEDULE_TIMEOUT); + return MAX_SCHEDULE_TIMEOUT; + } + + return (timeout * HZ) < MAX_SCHEDULE_TIMEOUT ? + timeout * HZ : MAX_SCHEDULE_TIMEOUT; } /* -- 1.8.5.5.dirty . -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
