Messages in this thread Patch in this message | | | Date | Thu, 6 Mar 2014 15:19:30 +0800 | From | Liu hua <> | Subject | [PATCH] hung_task : check the value of "sysctl_hung_task_timeout_sec" |
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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 <sdu.liu@huawei.com> --- 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
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