ffi: throw on fast calls to a closed library - #64855
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Close() marks every FFIFunction closed, but the generated fast-call path never sees it: V8 embeds the trampoline address when it compiles the call site, so an optimized call jumps into the library that dlclose() unloaded. Freeing the trampoline in Close() instead would leave compiled code calling unmapped memory. Give each library a one-byte flag that Close() sets and test it in the JavaScript wrapper before entering the trampoline. Fast signatures that need no argument conversion were handed to user code as the raw function, so they now get a guard-only wrapper too. Signed-off-by: Trivikram Kamat <16024985+trivikr@users.noreply.github.com> Assisted-by: claude:opus-5
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July 31, 2026 03:03
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Replaced by https://www.github.com/nodejs/node/pull/64860 |
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Fixes: #64854
The
closedchecks in the C++ invokers cannot run on the fast-call path, since V8 embeds the trampoline address when it compiles the call site. So eachDynamicLibrarygets a one-byte flag thatClose()sets, and the JS wrapper tests it before entering the trampoline; freeing the trampoline instead would leave compiled code calling unmapped memory.That only works if every fast function is wrapped, so
CreateFunction()now attacheskFastArgumentsto all of them and signatures needing no argument conversion get a guard-only wrapper. For those signatureslib.functionsand friends now return a JS wrapper instead of a native function, withname,length, andpointercarried over.Assisted-by: claude:opus-5