Re: [PATCH 0/2] freezer,sched: do not restore saved_state of a thawed task

[Peter Zijlstra]

On Tue, Nov 28, 2023 at 11:33:23AM -0600, Elliot Berman wrote:
> 
> 
> On 11/28/2023 11:31 AM, Peter Zijlstra wrote:
> > On Tue, Nov 28, 2023 at 05:12:00PM +0800, Aiqun(Maria) Yu wrote:
> >> On 11/21/2023 1:36 AM, Elliot Berman wrote:
> >>> This series applies couple fixes to commit 8f0eed4a78a8 ("freezer,sched:
> >>> Use saved_state to reduce some spurious wakeups") which was found while
> >>> testing with legacy cgroup freezer. My original testing was only with
> >>> system-wide freezer. We found that thaw_task could be called on a task
> >>> which was already frozen. Prior to commit 8f0eed4a78a8 ("freezer,sched:
> >>> Use saved_state to reduce some spurious wakeups"), this wasn't an issue
> >>> as kernel would try to wake up TASK_FROZEN, which wouldn't match the
> >>> thawed task state, and no harm done to task. After commit 8f0eed4a78a8
> >>> ("freezer,sched: Use saved_state to reduce some spurious wakeups"), it
> >>> was possible to overwrite the state of thawed task.
> >>>
> >>> To: Rafael J. Wysocki <rafael@xxxxxxxxxx>
> >>> To: Pavel Machek <pavel@xxxxxx>
> >>> To: Ingo Molnar <mingo@xxxxxxxxxx>
> >>> To: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> >>> Cc:  <linux-arm-msm@xxxxxxxxxxxxxxx>
> >>> Cc: Pavan Kondeti <quic_pkondeti@xxxxxxxxxxx>
> >>> Cc: Aiqun Yu (Maria) <quic_aiquny@xxxxxxxxxxx>
> >>> Cc:  <linux-pm@xxxxxxxxxxxxxxx>
> >>> Cc:  <linux-kernel@xxxxxxxxxxxxxxx>
> >>> Signed-off-by: Elliot Berman <quic_eberman@xxxxxxxxxxx>
> >> Shall we add Fixed tag and Cc: stable@xxxxxxxxxxxxxxx ?
> >> Since it is fixing a stable user thread hung issue.
> > 
> > If you want this routed through urgent, then yes.
> 
> Fixes tag is added to https://lore.kernel.org/all/20231120-freezer-state-multiple-thaws-v1-1-f2e1dd7ce5a2@xxxxxxxxxxx/
> 
> Is CC'ing stable what triggers routing through urgent?

Fixes tag should be enough, lemme go find that other copy then.. so much
email :/