Adding stable and lkml.
Sorry for spam others.
-Mukesh
On 7/23/2018 1:57 PM, Mukesh Ojha wrote:
Hi All,
I wanted to discuss about one of the corner case exists in 4.9 kernel
(4.9.x) where
If hotplug of one of the CPU fails due to failure in one of the callback,
which is to be called after "notify:online"(as notify_online will
create sysfs nodes
for the hotplug cpu) .
So, while cleaning up notify_dead() does not get called as step
<https://elixir.bootlin.com/linux/v4.9/ident/step>->skip_onerr set to
true for "notify:prepare"and due to that sysfs nodes of that cpu does
not get
cleaned up which can cause issue in next hotplug attempt of that cpu.
Fails
cpuhp_up_callbacks
<https://elixir.bootlin.com/linux/v4.9/ident/cpuhp_up_callbacks> =>
cpuhp_invoke_callback
<https://elixir.bootlin.com/linux/v4.9/ident/cpuhp_invoke_callback> =>
undo_cpu_up <https://elixir.bootlin.com/linux/v4.9/ident/undo_cpu_up>
.name = "notify:prepare",
.teardown.single = notify_dead
<https://elixir.bootlin.com/linux/v4.9/ident/notify_dead>,
.skip_onerr = true,
I think the possible solution here could be to remove the
- .skip_onerr = true,
for "notify:prepare"so that CPU_DEAD notification get send.
Please, feel free to suggest if it has any side-effect as i don't feel
any.
Ref:
https://elixir.bootlin.com/linux/v4.9/source/kernel/cpu.c#L458
Cheers,
Mukesh
