From: Cherry Zhang Date: Thu, 22 Apr 2021 15:12:21 +0000 (-0400) Subject: runtime: call cgocallbackg indirectly X-Git-Tag: go1.17beta1~501 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=d3853fb4e6ee2b9f873ab2e41adc0e62a82e73e4;p=gostls13.git runtime: call cgocallbackg indirectly cgocallback calls cgocallbackg after switching the stack. Call it indirectly to bypass the linker's nosplit check. Apparently (at least on Windows) cgocallbackg can use quite a bit stack space in a nosplit chain. We have been running over the nosplit limit, or very close to the limit. Since it switches stack in cgocallback, it is not meaningful to count frames above cgocallback and below cgocallbackg together. Bypass the check. For #45658. Change-Id: Ie22017e3f82d2c1fcc37336696f2d02757856399 Reviewed-on: https://go-review.googlesource.com/c/go/+/312669 Trust: Cherry Zhang Reviewed-by: Michael Knyszek Run-TryBot: Cherry Zhang TryBot-Result: Go Bot --- diff --git a/src/runtime/asm_amd64.s b/src/runtime/asm_amd64.s index d2848e5a45..789e159c76 100644 --- a/src/runtime/asm_amd64.s +++ b/src/runtime/asm_amd64.s @@ -911,7 +911,8 @@ havem: MOVQ BX, 0(SP) MOVQ CX, 8(SP) MOVQ DX, 16(SP) - CALL runtime·cgocallbackg(SB) + MOVQ $runtime·cgocallbackg(SB), AX + CALL AX // indirect call to bypass nosplit check. We're on a different stack now. // Compute the size of the frame again. FP and SP have // completely different values here than they did above,