Messages in this thread Patch in this message | | | Date | Mon, 23 Nov 2015 08:21:29 -0800 | From | tip-bot for Oleg Nesterov <> | Subject | [tip:sched/core] stop_machine: Fix possible cpu_stopper_thread() crash |
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Commit-ID: 64038f292a1b33c7d46bd11f62f7798101152c00 Gitweb: http://git.kernel.org/tip/64038f292a1b33c7d46bd11f62f7798101152c00 Author: Oleg Nesterov <oleg@redhat.com> AuthorDate: Sun, 15 Nov 2015 20:33:11 +0100 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Mon, 23 Nov 2015 09:48:17 +0100
stop_machine: Fix possible cpu_stopper_thread() crash
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> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Milos Vyletel <milos@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20151115193311.GA8242@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org> --- kernel/stop_machine.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
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 */
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