I was given a scare today by an unnamed party because calling
pool_init twice causes bad things to happen. And whenever bad things
happen in pool, I get blamed. To turn future tedu panics into kernel
panics, here's a diff.
Whenever pool_init is called, we check the list of existing
pools to make sure it's not already there. Along similar lines,
shuffle the pool_destroy code around to add the reverse check and do
so before touching any of the fields inside the pool.
Index: subr_pool.c
===================================================================
RCS file: /cvs/src/sys/kern/subr_pool.c,v
retrieving revision 1.118
diff -u -p -r1.118 subr_pool.c
--- subr_pool.c 6 Apr 2013 13:41:11 -0000 1.118
+++ subr_pool.c 9 Apr 2013 01:56:35 -0000
@@ -244,6 +244,14 @@ pool_init(struct pool *pp, size_t size,
const char *wchan, struct pool_allocator *palloc)
{
int off, slack;
+#ifdef DIAGNOSTIC
+ struct pool *iter;
+
+ SIMPLEQ_FOREACH(iter, &pool_head, pr_poollist) {
+ if (iter == pp)
+ panic("init pool already on list");
+ }
+#endif
#ifdef MALLOC_DEBUG
if ((flags & PR_DEBUG) && (ioff != 0 || align != 0))
@@ -417,17 +425,6 @@ pool_destroy(struct pool *pp)
struct pool_item_header *ph;
struct pool *prev, *iter;
-#ifdef DIAGNOSTIC
- if (pp->pr_nout != 0)
- panic("pool_destroy: pool busy: still out: %u", pp->pr_nout);
-#endif
-
- /* Remove all pages */
- while ((ph = LIST_FIRST(&pp->pr_emptypages)) != NULL)
- pr_rmpage(pp, ph, NULL);
- KASSERT(LIST_EMPTY(&pp->pr_fullpages));
- KASSERT(LIST_EMPTY(&pp->pr_partpages));
-
/* Remove from global pool list */
if (pp == SIMPLEQ_FIRST(&pool_head))
SIMPLEQ_REMOVE_HEAD(&pool_head, pr_poollist);
@@ -437,11 +434,26 @@ pool_destroy(struct pool *pp)
if (iter == pp) {
SIMPLEQ_REMOVE_AFTER(&pool_head, prev,
pr_poollist);
- break;
+ goto removed;
}
prev = iter;
}
+#ifdef DIAGNOSTIC
+ panic("destroyed pool not on list");
+#endif
}
+removed:
+#ifdef DIAGNOSTIC
+ if (pp->pr_nout != 0)
+ panic("pool_destroy: pool busy: still out: %u", pp->pr_nout);
+#endif
+
+ /* Remove all pages */
+ while ((ph = LIST_FIRST(&pp->pr_emptypages)) != NULL)
+ pr_rmpage(pp, ph, NULL);
+ KASSERT(LIST_EMPTY(&pp->pr_fullpages));
+ KASSERT(LIST_EMPTY(&pp->pr_partpages));
+
}
struct pool_item_header *
