| From 923499cb1cf693b1f4e35711a34568864898876a Mon Sep 17 00:00:00 2001 |
| From: Kevin Hao <kexin.hao@windriver.com> |
| Date: Tue, 2 Mar 2010 16:51:58 -0500 |
| Subject: [PATCH] rtmutex: Preserve TASK_STOPPED state when blocking on a "spin_lock" |
| |
| commit 923499cb1cf693b1f4e35711a34568864898876a in tip. |
| |
| 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@windriver.com> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| LKML-Reference: <18e240905fcfd72457930322ee187e7ff9313aec.1267566249.git.paul.gortmaker@windriver.com> |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| |
| 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; |
| |
| -- |
| 1.7.1.1 |
| |
