From: Kevin Hao <kexin.hao@xxxxxxxxxxxxx> When a process handles a SIGSTOP signal, it will set the state to TASK_STOPPED, acquire tasklist_lock and notifiy the parent of the status change. But in the rt kernel the process state will change to TASK_UNINTERRUPTIBLE if it blocks on the tasklist_lock. So if we send a SIGCONT signal to this process at this time, the SIGCONT signal just does nothing because this process is not in TASK_STOPPED state. Of course this is not what we wanted. Preserving the TASK_STOPPED state when blocking on a spin lock can fix this bug. Signed-off-by: Kevin Hao <kexin.hao@xxxxxxxxxxxxx> Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx> --- kernel/rtmutex.c | 5 +++-- 1 files changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c index 16bfa1c..23dd443 100644 --- a/kernel/rtmutex.c +++ b/kernel/rtmutex.c @@ -757,8 +757,9 @@ rt_set_current_blocked_state(unsigned long saved_state) * saved_state. Now we can ignore further wakeups as we will * return in state running from our "spin" sleep. */ - if (saved_state == TASK_INTERRUPTIBLE) - block_state = TASK_INTERRUPTIBLE; + if (saved_state == TASK_INTERRUPTIBLE || + saved_state == TASK_STOPPED) + block_state = saved_state; else block_state = TASK_UNINTERRUPTIBLE; -- 1.6.5.2 -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
