RFR: 8344802: Crash in StubRoutines::verify_mxcsr with -XX:+EnableX86ECoreOpts and -Xcheck:jni [v7]
Volodymyr Paprotski
vpaprotski at openjdk.org
Wed Feb 12 15:47:04 UTC 2025
> (Also see `8319429: Resetting MXCSR flags degrades ecore`)
>
> This PR fixes two issues:
> - the original issue is a crash caused by `__ warn` corrupting the stack on Windows only
> - This issue also uncovered that -Xcheck:jni test cases were getting 65k lines of warning on HelloWorld (on both Linux _and_ windows):
>
> OpenJDK 64-Bit Server VM warning: MXCSR changed by native JNI code, use -XX:+RestoreMXCSROnJNICall
>
>
> First, the crash. Caused when FXRSTOR is attempting to write reserved bits into MXCSR. If those bits happen to be set, crash. (Hence the crash isn't deterministic. But frequent enough if `__ warn` is used). It is caused by the binding not reserving stack space for register parameters ()
> 
> Prolog of the warn function then proceeds to store the for arg registers onto the stack, overriding the fxstore save area. (See https://learn.microsoft.com/en-us/cpp/build/x64-calling-convention?view=msvc-170#calling-convention-defaults)
>
> Fix uses `frame::arg_reg_save_area_bytes` to bump the stack pointer.
>
> ---
>
> I also kept the fix to `verify_mxcsr` since without it, `-Xcheck:jni` is practically unusable when `-XX:+EnableX86ECoreOpts` are set (65k+ lines of warnings)
Volodymyr Paprotski has updated the pull request incrementally with one additional commit since the last revision:
Update src/hotspot/cpu/x86/macroAssembler_x86.cpp
Co-authored-by: Julian Waters <32636402+TheShermanTanker at users.noreply.github.com>
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/22673/files
- new: https://git.openjdk.org/jdk/pull/22673/files/b23764ab..cbd3812d
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=22673&range=06
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=22673&range=05-06
Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
Patch: https://git.openjdk.org/jdk/pull/22673.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/22673/head:pull/22673
PR: https://git.openjdk.org/jdk/pull/22673
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