Revert "Fix NetAcceptAction::cancel() use-after-free race condition"#12841
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Revert "Fix NetAcceptAction::cancel() use-after-free race condition"#12841
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bryancall
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Jan 29, 2026
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Should we remove Milestone from both this and #12803 ? I don't think these two need to be on 10.2 release note since nothing changed effectively. |
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Thanks. That's a good idea. |
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Yeah, definitely clear both the Milestones, unless the first one has been in a release. |
bneradt
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There is a race between NetAcceptAction::cancel() and NetAccept::acceptEvent() where the server pointer could be dereferenced after the NetAccept object was deleted. Thread A calls cancel(), which sets cancelled=true via Action::cancel(). Thread B running acceptEvent() sees cancelled==true and deletes the NetAccept (including the embedded Server). Thread A then calls server->close() on freed memory. This is fixed by making the server pointer in NetAcceptAction atomic and using exchange(nullptr) so only one thread can obtain and close the server. Additionally, cancel() is made idempotent by checking !cancelled before calling Action::cancel(), which prevents ink_assert(!cancelled) assertion failures when cancel is called from both external callers (TSActionCancel) and internal error paths (acceptEvent, acceptFastEvent, acceptLoopEvent). This is a revised version of PR apache#12803 which was reverted in PR apache#12841 because it lacked the idempotent cancel guard.
bneradt
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This is a revised version of PR apache#12803 which was reverted in PR apache#12841 because it lacked the idempotent cancel guard, causing its own set of crashes. There is a race between NetAcceptAction::cancel() and NetAccept::acceptEvent() where the server pointer could be dereferenced after the NetAccept object was deleted. Thread A calls cancel(), which sets cancelled=true via Action::cancel(). Thread B running acceptEvent() sees cancelled==true and deletes the NetAccept (including the embedded Server). Thread A then calls server->close() on freed memory. This is fixed by making the server pointer in NetAcceptAction atomic and using exchange(nullptr) so only one thread can obtain and close the server. Additionally, cancel() is made idempotent by checking !cancelled before calling Action::cancel(), which prevents ink_assert(!cancelled) assertion failures when cancel is called from both external callers (TSActionCancel) and internal error paths (acceptEvent, acceptFastEvent, acceptLoopEvent).
bneradt
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Feb 13, 2026
This is a revised version of PR #12803 which was reverted in PR #12841 because it lacked the idempotent cancel guard, causing its own set of crashes. There is a race between NetAcceptAction::cancel() and NetAccept::acceptEvent() where the server pointer could be dereferenced after the NetAccept object was deleted. Thread A calls cancel(), which sets cancelled=true via Action::cancel(). Thread B running acceptEvent() sees cancelled==true and deletes the NetAccept (including the embedded Server). Thread A then calls server->close() on freed memory. This is fixed by making the server pointer in NetAcceptAction atomic and using exchange(nullptr) so only one thread can obtain and close the server. Additionally, cancel() is made idempotent by checking !cancelled before calling Action::cancel(), which prevents ink_assert(!cancelled) assertion failures when cancel is called from both external callers (TSActionCancel) and internal error paths (acceptEvent, acceptFastEvent, acceptLoopEvent).
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Reverts #12803
I suspect this is introducing different crashes in NetAccept::cancel.