On Tue, 10 Dec 2024 23:45:37 GMT, Volodymyr Paprotski <vpaprot...@openjdk.org> wrote:
> (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) This pull request has now been integrated. Changeset: 55097dd4 Author: Volodymyr Paprotski <vpaprot...@openjdk.org> URL: https://git.openjdk.org/jdk/commit/55097dd4cbb5d691c12cb0247d66dce593759d59 Stats: 127 lines in 9 files changed: 66 ins; 54 del; 7 mod 8344802: Crash in StubRoutines::verify_mxcsr with -XX:+EnableX86ECoreOpts and -Xcheck:jni Reviewed-by: jwaters, kvn, sviswanathan ------------- PR: https://git.openjdk.org/jdk/pull/22673
