Messages in this thread | | | Date | Sun, 19 Apr 2015 11:31:13 +0200 | From | Ingo Molnar <> | Subject | Re: qemu:arm test failure due to commit 8053871d0f7f (smp: Fix smp_call_function_single_async() locking) |
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* Linus Torvalds <torvalds@linux-foundation.org> wrote:
> On Sun, Apr 19, 2015 at 4:48 AM, Linus Torvalds > <torvalds@linux-foundation.org> wrote: > > > > Does that smaller patch work equally well? > > .. and here's a properly formatted email and patch. > > Linus
> kernel/smp.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/kernel/smp.c b/kernel/smp.c > index 2aaac2c47683..07854477c164 100644 > --- a/kernel/smp.c > +++ b/kernel/smp.c > @@ -159,8 +159,10 @@ static int generic_exec_single(int cpu, struct call_single_data *csd, > } > > > - if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) > + if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) { > + csd_unlock(csd); > return -ENXIO; > + }
Acked-by: Ingo Molnar <mingo@kernel.org>
Btw., in this case we should probably also generate a WARN_ONCE() warning?
I _think_ most such callers calling an SMP function call for offline or out of range CPUs are at minimum racy.
Thanks,
Ingo
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