i#7044 sched deadlock: Fix theoretical deadlock #7087
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Adds a check for the caller holding the previous input's lock before acquiring it to retrieve the previous workload. The existing code acquired the new lock without checking caller_holds_cur_input_lock, which could hang (it happened not to because the only caller who sets caller_holds_cur_input_lock to true set the current input to invalid and set_cur_input() returns prior to this point). Issue: #7044
…ight call add_to_ready_queue
edeiana
approved these changes
Nov 15, 2024
No, since the only code path today where the caller holds the input lock is on replay and it doesn't hit either of these points. This would only happen on a future code change where some new call site holds the lock. So I think code inspection is the best we can do; but better than just leaving known possible problems in place. |
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a64 failure is #5641 timeout in sigmask-noalarm |
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Adds a check for the caller holding the previous input's lock before acquiring it to retrieve the previous workload. The existing code acquired the new lock without checking caller_holds_cur_input_lock, which could hang (it happened not to because the only caller who sets caller_holds_cur_input_lock to true set the current input to invalid and set_cur_input() returns prior to this point).
Issue: #7044