From: Ingo Molnar <mingo@elte.hu>
disable preemption in the self-reap codepath, as such tasks may not be on
the tasklist anymore and CPU-hotplug relies on the tasklist to migrate
tasks.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/kernel/exit.c | 7 +++++++
1 files changed, 7 insertions(+)
diff -puN kernel/exit.c~sched-self-reap-fix kernel/exit.c
--- 25/kernel/exit.c~sched-self-reap-fix 2004-08-20 02:04:27.375584976 -0700
+++ 25-akpm/kernel/exit.c 2004-08-20 02:04:27.382583912 -0700
@@ -24,6 +24,7 @@
#include <linux/proc_fs.h>
#include <linux/mempolicy.h>
#include <linux/perfctr.h>
+#include <linux/cpu.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -783,8 +784,14 @@ static void exit_notify(struct task_stru
/* If the process is dead, release it - nobody will wait for it */
if (state == TASK_DEAD) {
+ lock_cpu_hotplug();
release_task(tsk);
write_lock_irq(&tasklist_lock);
+ /*
+ * No preemption may happen from this point on,
+ * or CPU hotplug (and task exit) breaks:
+ */
+ unlock_cpu_hotplug();
tsk->state = state;
_raw_write_unlock(&tasklist_lock);
local_irq_enable();
_