Messages in this thread | | | From | Elliot Berman <> | Subject | [PATCH 0/2] freezer,sched: do not restore saved_state of a thawed task | Date | Mon, 20 Nov 2023 09:36:30 -0800 |
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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, -- Elliot Berman <quic_eberman@quicinc.com>
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