[6.1] Frequent crashes in LLBuildProgressTracker while building swift-java on linux and swift 6.1.2 #9019
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…on linux and swift 6.1.2 (swiftlang#8998) Frequent crashes in LLBuildProgressTracker while building swift-java on linux and swift 6.1.2 > Thread 4 crashed: > > 0 0x00007f1559da359a swift_slowAlloc + 74 in [libswiftCore.so](http://libswiftcore.so/) > 1 [ra] 0x00007f1559da3877 swift_allocObject + 38 in [libswiftCore.so](http://libswiftcore.so/) > 2 [ra] 0x00007f1559b85571 _allocateStringStorage(codeUnitCapacity:) + 160 in [libswiftCore.so](http://libswiftcore.so/) > 3 [ra] 0x00007f1559d03452 _StringGuts.grow(_:) + 273 in [libswiftCore.so](http://libswiftcore.so/) > 4 [ra] 0x00007f1559bf7e88 specialized static String._fromUTF8Repairing(_:) + 999 in [libswiftCore.so](http://libswiftcore.so/) > 5 [ra] [inlined] [system] 0x000056315a96e7ef specialized String.init<A, B>(decoding:as:) in swift-package at //<compiler-generated> > 6 [ra] [inlined] 0x000056315a96e7ef stringFromData(_:) in swift-package at /home/build-user/llbuild/products/llbuildSwift/Internals.swift:49:12 > 7 [ra] 0x000056315a96e7ef Command.name.getter + 78 in swift-package at /home/build-user/llbuild/products/llbuildSwift/BuildSystemBindings.swift:720:20 > 8 [ra] 0x00005631593a61a2 closure swiftlang#1 in LLBuildProgressTracker.commandProcessFinished(_:process:result:) + 33 in swift-package at /home/build-user/swiftpm/Sources/Build/LLBuildProgressTracker.swift:347:65 > 9 [ra] [thunk] 0x00005631592f6989 thunk for @escaping @callee_guaranteed @sendable () -> () + 24 in swift-package at //<compiler-generated> Command is associated with a handle (pointer) that may be reclaimed when this function finishes. Do not access command attributes asynchronously (cherry picked from commit 16452e1)
jakepetroules
approved these changes
Aug 13, 2025
|
@swift-ci test |
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@airspeedswift approved, merged. Thank you for the fix! |
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Explanation:
(cherry picked from commit 16452e1)
Frequent crashes in LLBuildProgressTracker while building swift-java on linux and swift 6.1.2
This was a race condition because the
Command is associated with a handle (pointer) that may be reclaimed when this function finishes.
Scope:
Minimal, copy variables into locals before accessing them from async block.
Issues:
swiftlang/swift-java#314 almost all CI runs fail with this race condition due to the timing of the command being influenced by the gradle build in swift-java.
Original PRs:
#8998
Risk:
Minimal. Change explicitly copies variables prior to usage in async block. This avoided a race condition that would manifest before as null pointer crashes when trying to access these variables.
Change has been tested in main and 6.2
Testing:
Confirmed fixed in main and 6.2. Manually verified in always reproducing project.