From d308b9f1e4412bcf583c82c4ca15ef97cb8b0e6f Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 30 Jun 2015 03:29:58 +0200 Subject: [PATCH] stop_machine: Remove cpu_stop_work's from list in cpu_stop_park() cpu_stop_park() does cpu_stop_signal_done() but leaves the work on stopper->works. The owner of this work can free/reuse this memory right after that and corrupt the list, so if this CPU becomes online again cpu_stopper_thread() will crash. Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Cc: Linus Torvalds Cc: Mike Galbraith Cc: Peter Zijlstra Cc: Tejun Heo Cc: Thomas Gleixner Cc: dave@stgolabs.net Cc: der.herr@hofr.at Cc: paulmck@linux.vnet.ibm.com Cc: riel@redhat.com Cc: viro@ZenIV.linux.org.uk Link: http://lkml.kernel.org/r/20150630012958.GA23944@redhat.com Signed-off-by: Ingo Molnar --- kernel/stop_machine.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index 9a70defe9f1f..12484e5d5c88 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -462,13 +462,15 @@ static void cpu_stop_create(unsigned int cpu) static void cpu_stop_park(unsigned int cpu) { struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu); - struct cpu_stop_work *work; + struct cpu_stop_work *work, *tmp; unsigned long flags; /* drain remaining works */ spin_lock_irqsave(&stopper->lock, flags); - list_for_each_entry(work, &stopper->works, list) + list_for_each_entry_safe(work, tmp, &stopper->works, list) { + list_del_init(&work->list); cpu_stop_signal_done(work->done, false); + } stopper->enabled = false; spin_unlock_irqrestore(&stopper->lock, flags); } -- 2.20.1