314243 2026-05-06 15:14:58 -0700 RELEASE ASSERT: http/tests/security/contentSecurityPolicy/multipart-three-part.py is a flaky crash 2026-05-12 18:53:15 -0700 1 1 1 Unclassified WebKit New Bugs WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 bfulgham cdumez webkit-bug-importer oldest_to_newest 2208300 0 bfulgham 2026-05-06 15:14:58 -0700 This issue can be reproduced using command: run-webkit-tests --no-build --no-retry --no-show-results --exit-after-n-failures=1 --expect-pass --iterations=1000 --force -f --clobber-old-results --release http/tests/security/contentSecurityPolicy/multipart-three-part.py <rdar://169360779> 2208302 1 bfulgham 2026-05-06 15:18:07 -0700 This crash has nothing to do with CSP — it is happening because the multi-part load happens in rapid succession, causing the first completion handler to be dropped when the second arrives. This triggers NSURLSession to fire a release assert that crashes the network process. if (willWaitForContinueDidReceiveResponse) { m_responseCompletionHandler = WTF::move(completionHandler); return; } The most conservative (from a loading standpoint) fix is to process the completion handler. I think that PolicyAction::Use is the correct argument (rather than PolicyAction::Ignore) because by the time we get a follow-up response, we have decided to proceed with the load and will need to accept the first (and all subsequent) loads to complete the process. 2208306 2 bfulgham 2026-05-06 15:22:54 -0700 Pull request: https://github.com/WebKit/WebKit/pull/64404 2209537 3 cdumez 2026-05-10 17:39:49 -0700 Pull request: https://github.com/WebKit/WebKit/pull/64646 2210352 4 ews-feeder 2026-05-12 18:53:13 -0700 Committed 313118@main (071edf4eff8a): <https://commits.webkit.org/313118@main> Reviewed commits have been landed. Closing PR #64646 and removing active labels.