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fix: system ID for Apache graceful restart - #24184
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morrisonlevi wants to merge 1 commit into
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morrisonlevi wants to merge 1 commit into
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Apache forks workers from a parent process. During a graceful restart, PHP shuts down and starts up again in that same parent process. However, `finalized` was not reset to 0 during subsequent startups, so all calls to `zend_add_system_entropy()` would fail. This could cause the process state to diverge from the system ID used to validate OPcache's file cache. For example, `zend_get_resource_handle()` would still allocate a handle, but its entropy would not contribute to the system ID. Enabling, disabling, or reordering extensions or features across graceful restarts could therefore change resource-slot assignments without a corresponding change to the system ID. Reset `finalized` when initializing the system ID so each startup can register fresh entropy.
morrisonlevi
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October 7, 2026 23:12
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Apache forks workers from a parent process. During a graceful restart, PHP shuts down and starts up again in that same parent process. New workers are then forked from the parent.
However,
finalizedwas not reset to 0 during subsequent startups, so all calls tozend_add_system_entropy()would fail. This could cause the process state to diverge from the system ID used to validate OPcache's file cache.For example,
zend_get_resource_handle()would still allocate a handle, but its entropy would not contribute to the system ID. Enabling, disabling, or reordering extensions or features across graceful restarts could therefore change resource-slot assignments without a corresponding change to the system ID.Reset
finalizedwhen initializing the system ID so each startup can register fresh entropy.I think this fix should definitely go into PHP 8.4+ but I think that RMs should consider pulling it for 8.2-8.3. It is not a dangerous change, it's simple, and easy to understand (well, assuming you already understand Apache graceful and system ID), and causes really nasty memory bugs when it's hit.