Commit 8db54949 authored Sep 11, 2016 by Peter Zijlstra Committed by Ingo Molnar Sep 22, 2016

smp: Allocate smp_call_on_cpu() workqueue on stack too



The SMP IPI struct descriptor is allocated on the stack except for the
workqueue and lockdep complains:

  INFO: trying to register non-static key.
  the code is fine but needs lockdep annotation.
  turning off the locking correctness validator.
  CPU: 0 PID: 110 Comm: kworker/0:1 Not tainted 4.8.0-rc5+ #14
  Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A13 05/11/2014
  Workqueue: events smp_call_on_cpu_callback
  ...
  Call Trace:
    dump_stack
    register_lock_class
    ? __lock_acquire
    __lock_acquire
    ? __lock_acquire
    lock_acquire
    ? process_one_work
    process_one_work
    ? process_one_work
    worker_thread
    ? process_one_work
    ? process_one_work
    kthread
    ? kthread_create_on_node
    ret_from_fork

So allocate it on the stack too.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[ Test and write commit message. ]
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20160911084323.jhtnpb4b37t5tlno@pd.tnic


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 27046a3f

kernel/smp.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -759,13 +759,14 @@ static void smp_call_on_cpu_callback(struct work_struct *work)
		int smp_call_on_cpu(unsigned int cpu, int (func)(void ), void *par, bool phys)
		{
		struct smp_call_on_cpu_struct sscs = {
		.work = __WORK_INITIALIZER(sscs.work, smp_call_on_cpu_callback),
		.done = COMPLETION_INITIALIZER_ONSTACK(sscs.done),
		.func = func,
		.data = par,
		.cpu = phys ? cpu : -1,
		};

		INIT_WORK_ONSTACK(&sscs.work, smp_call_on_cpu_callback);

		if (cpu >= nr_cpu_ids \|\| !cpu_online(cpu))
		return -ENXIO;

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