cvs commit: src/sys/alpha/alpha trap.c src/sys/i386/i386 trap.c src/sys/ia64/ia64 trap.c src/sys/kern kern_thread.c src/sys/sparc64/sparc64 trap.c

[John Baldwin]

On 19-Apr-2003 David Xu wrote:
> er, I found some code in i386/i386/trap.c:
> 
> PROC_LOCK(p);
>               if ((p->p_flag & P_WEXIT) && (p->p_singlethread != td)) {
>                       mtx_lock_spin(&sched_lock);
>                       thread_exit();
>                       /* NOTREACHED */
>               }
> PROC_UNLOCK(p);

1.246        (jhb      18-Apr-03):              PROC_LOCK(p);
1.228        (julian   29-Jun-02):              if ((p->p_flag & P_WEXIT) && (p-
>p_singlethread != td)) {
1.228        (julian   29-Jun-02):                      mtx_lock_spin(&sched_loc
k);
1.228        (julian   29-Jun-02):                      thread_exit();
1.228        (julian   29-Jun-02):                      /* NOTREACHED */
1.228        (julian   29-Jun-02):              }
1.246        (jhb      18-Apr-03):              PROC_UNLOCK(p);
 
> The P_WEXIT and p_singlethread will never be set at same
> time. see kern_exit.c. so the code never be executed. 
> replacing P_WEXIT with P_SINGLE_EXIT will work,
> and because 1:1 thread borrows KSE code, so you now need code
> like this:
> 
> PROC_LOCK(p);
> if ((p->p_flag & P_SINGLE_EXIT) && (p->p_singlethread != td)) {
> mtx_lock_spin(&sched_lock);
> if (p->p_flag & P_THREADED)
>     thread_exit();
> else
>     thr_exit();
> /* NOTREACHED */
> }
> PROC_UNLOCK(p);

Well, I'm only fixing locking, I'll leave fixing internal KSE bugs to
you. :)  If you wanted to consolidate this code into a thread_kern_enter()
or some such that would work for me.

> I suggest remove such code from trap.c, just keep it in kernel
> thread control code (e.g kern_thread.c or kern_thr.c) to reduce
> maintain overhead.
> 
> David Xu
> 
> ----- Original Message ----- 
> From: "John Baldwin" <jhb at FreeBSD.org>
> To: <src-committers at FreeBSD.org>; <cvs-src at FreeBSD.org>; <cvs-all at FreeBSD.org>
> Sent: Saturday, April 19, 2003 4:20 AM
> Subject: cvs commit: src/sys/alpha/alpha trap.c src/sys/i386/i386 trap.c src/sys/ia64/ia64 trap.c
> src/sys/kern kern_thread.c src/sys/sparc64/sparc64 trap.c
> 
> 
>> jhb         2003/04/18 13:20:00 PDT
>> 
>>   FreeBSD src repository
>> 
>>   Modified files:
>>     sys/alpha/alpha      trap.c 
>>     sys/i386/i386        trap.c 
>>     sys/ia64/ia64        trap.c 
>>     sys/kern             kern_thread.c 
>>     sys/sparc64/sparc64  trap.c 
>>   Log:
>>   Use the proc lock to protect p_singlethread and a P_WEXIT test.  This
>>   fixes a couple of potential KSE panics on non-i386 arch's that weren't
>>   holding the proc lock when calling thread_exit().
>>   
>>   Revision  Changes    Path
>>   1.111     +2 -1      src/sys/alpha/alpha/trap.c
>>   1.246     +2 -2      src/sys/i386/i386/trap.c
>>   1.73      +3 -1      src/sys/ia64/ia64/trap.c
>>   1.117     +2 -2      src/sys/kern/kern_thread.c
>>   1.59      +2 -1      src/sys/sparc64/sparc64/trap.c
> 

-- 

John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve!"  -  http://www.FreeBSD.org/