runtime: fix invalid pointer in windows/arm64 badsignal2

Initializes the R3 register with an available address in the stack. The addressed location is used to receive the number of bytes written by WriteFile. Fixes #56080 Change-Id: I0368eb7a31d2d6a098fa9c26e074eb1114a92704 GitHub-Last-Rev: 23dbdb5 GitHub-Pull-Request: #56153 Reviewed-on: https://go-review.googlesource.com/c/go/+/442216 Reviewed-by: Cherry Mui <[email protected]> TryBot-Result: Gopher Robot <[email protected]> Run-TryBot: Cherry Mui <[email protected]> Reviewed-by: Bryan Mills <[email protected]>
golang · Oct 12, 2022 · 4a4de14 · 4a4de14
1 parent 5bef938
commit 4a4de14
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/src/runtime/sys_windows_arm64.s b/src/runtime/sys_windows_arm64.s
@@ -113,7 +113,8 @@ TEXT runtime·badsignal2(SB),NOSPLIT,$16-0
 	MOVD	$runtime·badsignalmsg(SB), R1	// lpBuffer
 	MOVD	$runtime·badsignallen(SB), R2	// lpNumberOfBytesToWrite
 	MOVD	(R2), R2
-	MOVD	R13, R3		// lpNumberOfBytesWritten
+	// point R3 to stack local that will receive number of bytes written
+	ADD	$16, RSP, R3		// lpNumberOfBytesWritten
 	MOVD	$0, R4			// lpOverlapped
 	MOVD	runtime·_WriteFile(SB), R12
 	SUB	$16, RSP	// skip over saved frame pointer below RSP