On 04/19/2015 02:31 AM, Ingo Molnar wrote:
* Linus Torvalds <torva...@linux-foundation.org> wrote:
On Sun, Apr 19, 2015 at 4:48 AM, Linus Torvalds
<torva...@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 <mi...@kernel.org>
Tested-by: Guenter Roeck <li...@roeck-us.net>
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.
Not really; at least the online cpu part is an absolutely normal use
case for qemu-arm.
Sure, you can argue that "this isn't the real system", and that
qemu-arm should be "fixed", but there are reasons - the emulation
is (much) slower if the number of CPUs is set to 4, and not everyone
who wants to use qemu has a system with as many CPUs as the emulated
system would normally have.
Thanks,
Guenter
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