Re: resource leak in linux emulation?

[christos%astron.com@localhost (Christos Zoulas)]

In article <201405040936.21907.mark%ecs.vuw.ac.nz@localhost>,
Mark Davies  <mark%ecs.vuw.ac.nz@localhost> wrote:
>On Thu, 24 Apr 2014 07:18:10 David Laight wrote:
>> > To fix, this should be added somewhere, probably at
>> > sys/kern/kern_exit.c:487 (but I'm not sure if there's a better
>> > location):
>> >         if ((l->l_pflag & LP_PIDLID) != 0 && l->l_lid != p->p_pid) {
>> >         
>> >                 proc_free_pid(l->l_lid);
>> >         
>> >         }
>> 
>> That doesn't look like the right place.
>> I think it should be further down (and with proc_lock held).
>
>So can someone suggest where exactly the patch should go.  And isn't proc_lock 
>held at this point (entered at line 344, exit at line 569)?

How about this?

christos

Index: kern_exit.c
===================================================================
RCS file: /cvsroot/src/sys/kern/kern_exit.c,v
retrieving revision 1.243
diff -u -u -r1.243 kern_exit.c
--- kern_exit.c 9 Jun 2013 01:13:47 -0000       1.243
+++ kern_exit.c 4 May 2014 21:26:00 -0000
@@ -541,12 +541,10 @@
         */
        pcu_discard_all(l);
 
-       /*
-        * Remaining lwp resources will be freed in lwp_exit2() once we've
-        * switch to idle context; at that point, we will be marked as a
-        * full blown zombie.
-        */
        mutex_enter(p->p_lock);
+       /* Free the linux lwp id */
+       if ((l->l_pflag & LP_PIDLID) != 0 && l->l_lid != p->p_pid)
+               proc_free_pid(l->l_lid);
        lwp_drainrefs(l);
        lwp_lock(l);
        l->l_prflag &= ~LPR_DETACHED;