Bug 202150 – [JSC] Null dereference in propagateTransitions

• Status: RESOLVED
• Resolution: DUPLICATE
• Component: JavaScriptCore

[Antonio Groza]

Hello, 
While fuzzing JSC i have found a test case that is able to reproduce the following issue: https://bugs.webkit.org/show_bug.cgi?id=200983 .

function hax() {
for (const v3 in "AAAAAAAAAAA") {
    const v4 = createGlobalObject();
    with (v4) {
        v4.b = parseInt;
        v4.length = v3;
        const v6 = new Uint16Array();
    }
}
}

hax();

Execute it on an ASAN build of JSC with the following options to repro: 

./jsc --useConcurrentJIT=false --useConcurrentGC=false --thresholdForJITSoon=10 --thresholdForJITAfterWarmUp=10 --thresholdForOptimizeAfterWarmUp=100 --thresholdForOptimizeAfterLongWarmUp=100 --thresholdForOptimizeAfterLongWarmUp=100 --thresholdForFTLOptimizeAfterWarmUp=1000 --thresholdForFTLOptimizeSoon=1000 --gcAtEnd=true poc.js

[Radar WebKit Bug Importer]

<rdar://problem/55721330>

[Tadeu Zagallo]

*** This bug has been marked as a duplicate of bug 202122 ***