sched: domain sysctl fixes: unregister the sysctl table before domains
Unregister and free the sysctl table before destroying domains, then
rebuild and register after creating the new domains. This prevents the
sysctl table from pointing to freed memory for root to write.
Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched.c b/kernel/sched.c
index 374f421..a2dd054 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -5250,6 +5250,18 @@
return entry;
}
+static void sd_free_ctl_entry(struct ctl_table **tablep)
+{
+ struct ctl_table *entry = *tablep;
+
+ for (entry = *tablep; entry->procname; entry++)
+ if (entry->child)
+ sd_free_ctl_entry(&entry->child);
+
+ kfree(*tablep);
+ *tablep = NULL;
+}
+
static void
set_table_entry(struct ctl_table *entry,
const char *procname, void *data, int maxlen,
@@ -5318,7 +5330,7 @@
}
static struct ctl_table_header *sd_sysctl_header;
-static void init_sched_domain_sysctl(void)
+static void register_sched_domain_sysctl(void)
{
int i, cpu_num = num_online_cpus();
struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
@@ -5335,8 +5347,18 @@
}
sd_sysctl_header = register_sysctl_table(sd_ctl_root);
}
+
+static void unregister_sched_domain_sysctl(void)
+{
+ unregister_sysctl_table(sd_sysctl_header);
+ sd_sysctl_header = NULL;
+ sd_free_ctl_entry(&sd_ctl_dir[0].child);
+}
#else
-static void init_sched_domain_sysctl(void)
+static void register_sched_domain_sysctl(void)
+{
+}
+static void unregister_sched_domain_sysctl(void)
{
}
#endif
@@ -6271,6 +6293,8 @@
err = build_sched_domains(&cpu_default_map);
+ register_sched_domain_sysctl();
+
return err;
}
@@ -6287,6 +6311,8 @@
{
int i;
+ unregister_sched_domain_sysctl();
+
for_each_cpu_mask(i, *cpu_map)
cpu_attach_domain(NULL, i);
synchronize_sched();
@@ -6317,6 +6343,8 @@
if (!err && !cpus_empty(*partition2))
err = build_sched_domains(partition2);
+ register_sched_domain_sysctl();
+
return err;
}
@@ -6448,8 +6476,6 @@
/* XXX: Theoretical race here - CPU may be hotplugged now */
hotcpu_notifier(update_sched_domains, 0);
- init_sched_domain_sysctl();
-
/* Move init over to a non-isolated CPU */
if (set_cpus_allowed(current, non_isolated_cpus) < 0)
BUG();
