[PATCH 1/8] stop_machine: cpu_stopper_thread() must check done != NULL

Oleg Nesterov
2015-11-15T18:37:13Z

stop_one_cpu_nowait(fn) will crash the kernel if the callback returns
nonzero, work->done == NULL in this case.

This needs more cleanups, cpu_stop_signal_done() is called right after
we check done != NULL and it does the same check.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
kernel/stop_machine.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 867bc20..1a66a95 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -454,7 +454,7 @@ repeat:
preempt_disable();

ret = fn(arg);
- if (ret)
+ if (ret && done)
done->ret = ret;

/* restore preemption and check it's still balanced */
--
1.5.5.1