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Exclude non-user portions of the main thread stack from stack scanning on 32 bits. - #1571
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magomez merged 1 commit intoOct 10, 2025
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…g on 32 bits. https://bugs.webkit.org/show_bug.cgi?id=293720 Reviewed by Yusuke Suzuki. On 32-bit armv7/linux we run into an issue where the environment strings located at the bottom of the stack, as well as some random bits inside the libc portion of the stack are interpreted as cells pointing into the heap, keeping actually dead objects alive. Yusuke previously attempted to fix this by excluding environ and before, but there are additional fake roots only a few hundred bytes below that. This patch excludes the caller of main entirely. * Source/JavaScriptCore/jsc.cpp: (jscmain): * Source/JavaScriptCore/runtime/JSLock.cpp: (JSC::JSLock::didAcquireLock): * Source/WTF/wtf/StackBounds.cpp: (WTF::StackBounds::setBottomOfMainThreadMain): (WTF::StackBounds::currentThreadStackBoundsInternal): * Source/WTF/wtf/StackBounds.h: (WTF::StackBounds::checkConsistency const): * Source/WebKit/WebProcess/gtk/WebProcessMainGtk.cpp: (WebKit::WebProcessMain): * Source/WebKit/WebProcess/wpe/WebProcessMainWPE.cpp: (WebKit::WebProcessMain):
magomez
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Oct 10, 2025
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Exclude non-user portions of the main thread stack from stack scanning on 32 bits.
https://bugs.webkit.org/show_bug.cgi?id=293720
Reviewed by NOBODY (OOPS!).
On 32-bit armv7/linux we run into an issue where the environment strings
located at the bottom of the stack, as well as some random bits inside
the libc portion of the stack are interpreted as cells pointing
into the heap, keeping actually dead objects alive.
Yusuke previously attempted to fix this by excluding environ and before,
but there are additional fake roots only a few hundred bytes below that.
This patch excludes the caller of main entirely.
(jscmain):
(WTF::StackBounds::setBottomOfMainThreadMain):
(WTF::StackBounds::currentThreadStackBoundsInternal):
0f53210