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

Message ID 20231120-freezer-state-multiple-thaws-v1-0-a4c453f50745@quicinc.com (mailing list archive)
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Series freezer,sched: do not restore saved_state of a thawed task | expand

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Elliot Berman Nov. 20, 2023, 5:34 p.m. UTC 
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.

Signed-off-by: Elliot Berman <quic_eberman@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,