| Message ID | 20231120-freezer-state-multiple-thaws-v1-0-f2e1dd7ce5a2@quicinc.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | freezer,sched: do not restore saved_state of a thawed task | expand |
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@kernel.org> > To: Pavel Machek <pavel@ucw.cz> > To: Ingo Molnar <mingo@kernel.org> > To: Peter Zijlstra (Intel) <peterz@infradead.org> > Cc: <linux-arm-msm@vger.kernel.org> > Cc: Pavan Kondeti <quic_pkondeti@quicinc.com> > Cc: Aiqun Yu (Maria) <quic_aiquny@quicinc.com> > Cc: <linux-pm@vger.kernel.org> > Cc: <linux-kernel@vger.kernel.org> > Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> Shall we add Fixed tag and Cc: stable@vger.kernel.org ? Since it is fixing a stable user thread hung issue. > > Originally sent to only linux-arm-msm, resending to correct authors. > - Link to v1: https://lore.kernel.org/r/20231120-freezer-state-multiple-thaws-v1-0-a4c453f50745@quicinc.com > > --- > Elliot Berman (2): > freezer,sched: do not restore saved_state of a thawed task > freezer,sched: clean saved_state when restoring it during thaw > > kernel/freezer.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > --- > base-commit: 6d7e4782bcf549221b4ccfffec2cf4d1a473f1a3 > change-id: 20231108-freezer-state-multiple-thaws-7a3a8d9dadb3 > > Best regards,
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@kernel.org> > > To: Pavel Machek <pavel@ucw.cz> > > To: Ingo Molnar <mingo@kernel.org> > > To: Peter Zijlstra (Intel) <peterz@infradead.org> > > Cc: <linux-arm-msm@vger.kernel.org> > > Cc: Pavan Kondeti <quic_pkondeti@quicinc.com> > > Cc: Aiqun Yu (Maria) <quic_aiquny@quicinc.com> > > Cc: <linux-pm@vger.kernel.org> > > Cc: <linux-kernel@vger.kernel.org> > > Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> > Shall we add Fixed tag and Cc: stable@vger.kernel.org ? > Since it is fixing a stable user thread hung issue. If you want this routed through urgent, then yes.
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@kernel.org> >>> To: Pavel Machek <pavel@ucw.cz> >>> To: Ingo Molnar <mingo@kernel.org> >>> To: Peter Zijlstra (Intel) <peterz@infradead.org> >>> Cc: <linux-arm-msm@vger.kernel.org> >>> Cc: Pavan Kondeti <quic_pkondeti@quicinc.com> >>> Cc: Aiqun Yu (Maria) <quic_aiquny@quicinc.com> >>> Cc: <linux-pm@vger.kernel.org> >>> Cc: <linux-kernel@vger.kernel.org> >>> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> >> Shall we add Fixed tag and Cc: stable@vger.kernel.org ? >> 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@quicinc.com/ Is CC'ing stable what triggers routing through urgent? Thanks, Elliot
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@kernel.org> > >>> To: Pavel Machek <pavel@ucw.cz> > >>> To: Ingo Molnar <mingo@kernel.org> > >>> To: Peter Zijlstra (Intel) <peterz@infradead.org> > >>> Cc: <linux-arm-msm@vger.kernel.org> > >>> Cc: Pavan Kondeti <quic_pkondeti@quicinc.com> > >>> Cc: Aiqun Yu (Maria) <quic_aiquny@quicinc.com> > >>> Cc: <linux-pm@vger.kernel.org> > >>> Cc: <linux-kernel@vger.kernel.org> > >>> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> > >> Shall we add Fixed tag and Cc: stable@vger.kernel.org ? > >> 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@quicinc.com/ > > Is CC'ing stable what triggers routing through urgent? Fixes tag should be enough, lemme go find that other copy then.. so much email :/
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@kernel.org> To: Pavel Machek <pavel@ucw.cz> To: Ingo Molnar <mingo@kernel.org> To: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <linux-arm-msm@vger.kernel.org> Cc: Pavan Kondeti <quic_pkondeti@quicinc.com> Cc: Aiqun Yu (Maria) <quic_aiquny@quicinc.com> Cc: <linux-pm@vger.kernel.org> Cc: <linux-kernel@vger.kernel.org> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com> Originally sent to only linux-arm-msm, resending to correct authors. - Link to v1: https://lore.kernel.org/r/20231120-freezer-state-multiple-thaws-v1-0-a4c453f50745@quicinc.com --- Elliot Berman (2): freezer,sched: do not restore saved_state of a thawed task freezer,sched: clean saved_state when restoring it during thaw kernel/freezer.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- base-commit: 6d7e4782bcf549221b4ccfffec2cf4d1a473f1a3 change-id: 20231108-freezer-state-multiple-thaws-7a3a8d9dadb3 Best regards,