Date: Thu, 26 Sep 2002 10:43:30 +0100 From: Mark Murray <mark@grondar.za> To: arch@freebsd.org Subject: [patch] module-with-thread exit routine. Message-ID: <200209260943.g8Q9hURP072845@grimreaper.grondar.org>
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Hi
If an unloadable module has a thread (like random.ko has), then
unloading the module is problematic because of the race between
the module termination and the unload.
The thread must "die" in a part of the code that will not be
unloaded.
The random device has its own code to do this, but I think this
is better put with the kthread stuff.
Attached is a patch to the kthread code. I've been running this
for at least three months.
Comments?
M
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o Mark Murray
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O.\_ Warning: this .sig is umop ap!sdn
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Content-Description: kthread.diff
Index: kern/kern_kthread.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_kthread.c,v
retrieving revision 1.24
diff -u -d -r1.24 kern_kthread.c
--- kern/kern_kthread.c 11 Sep 2002 08:13:53 -0000 1.24
+++ kern/kern_kthread.c 11 Sep 2002 11:14:02 -0000
@@ -133,6 +133,19 @@
PROC_UNLOCK(p);
sx_xunlock(&proctree_lock);
exit1(td, W_EXITCODE(ecode, 0));
+ /* NOTREACHED */
+}
+
+
+/* Helper routine to enable kthread_exit() to work while a module is
+ * being (or has been) unloaded.
+ */
+void
+kthread_set_wakeup_exit(void *control)
+{
+ wakeup(control);
+ kthread_exit(0);
+ /* NOTREACHED */
}
/*
Index: sys/kthread.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/kthread.h,v
retrieving revision 1.7
diff -u -d -r1.7 kthread.h
--- sys/kthread.h 19 Mar 2002 20:18:36 -0000 1.7
+++ sys/kthread.h 19 Jul 2002 20:14:32 -0000
@@ -47,6 +47,7 @@
int kthread_create(void (*)(void *), void *, struct proc **,
int flags, const char *, ...) __printflike(5, 6);
void kthread_exit(int) __dead2;
+void kthread_set_wakeup_exit(void *) __dead2;
int kthread_resume(struct proc *); /* XXXKSE */
int kthread_suspend(struct proc *, int); /* XXXKSE */
void kthread_suspend_check(struct proc *); /* XXXKSE */
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