[iOS] Fixes race condition when setup image loader#46153
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@andrewdacenko has imported this pull request. If you are a Meta employee, you can view this diff on Phabricator. |
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@andrewdacenko merged this pull request in 6b104bb. |
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This pull request was successfully merged by @zhongwuzw in 6b104bb When will my fix make it into a release? | How to file a pick request? |
This was referenced Jun 20, 2026
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…erForData: (#57297) Summary: `imageURLLoaderForURL:` had a broken double-checked lock on `_loaders`: the outer `if (!_loaders)` guard and the `for` loop iteration both ran without `_loadersMutex`, while the assignment ran inside it. `imageDataDecoderForData:` had no lock at all on `_decoders`. Both methods write the ivar in two steps (raw list then sorted), so a concurrent reader could observe the intermediate value and iterate a concurrently-released array, crashing with `EXC_BAD_ACCESS` in `objc_release` on a GCD worker thread. Verified with a reproducer — crashes 5/5 without the fix, 0/10 with it: https://github.com/mfazekas/rn-rctimageloader-dcl-repro ## Fix Build the loader and decoder lists once in `setUp` (alongside the URL request queue), under `_setupLock` and gated by the existing `_didSetup` atomic flag. Every entry point calls `setUp` before reading the now write-once `_loaders` and `_decoders`, so a reader can never observe a half-built or concurrently-released array. This replaces the broken double-checked lock where the outer `if (!_loaders)` guard and the `for` loop iteration ran outside the mutex. ## Changelog: [iOS] [Fixed] - Fix a data race in `RCTImageLoader` loader and decoder lazy initialization that could crash with `EXC_BAD_ACCESS` ## Related Fixes #57296 See also #46115, #46153 Pull Request resolved: #57297 Reviewed By: javache Differential Revision: D109404243 Pulled By: fabriziocucci fbshipit-source-id: 359d4c70e2cbe1bc70a7e6a1dadc3e3b89c59ff4
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Summary:
Fixes #46115 .
Changelog:
[IOS] [FIXED] - Fixes race condition when setup image loader
Test Plan:
crash in #46115