Revert "runtime: normalize sigprof traceback flags"

This reverts commit CL 358900.

Adding _TraceJumpStack to cgo traceback exposed a crashing condition.
This CL was primarily a cleanup, so we revert it entirely for now
and follow-up with the VDSO and libcall parts later.

Fixes #50936.

Change-Id: Ie45c9caaa8e2ef5bc9498ba65c36c887ca821bf7
Reviewed-on: https://go-review.googlesource.com/c/go/+/382079
Reviewed-by: Cherry Mui <cherryyz@google.com>
Trust: Michael Pratt <mpratt@google.com>
Run-TryBot: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

src/runtime/proc.go

@@ -4671,7 +4671,6 @@ func sigprof(pc, sp, lr uintptr, gp *g, mp *m) {
 	getg().m.mallocing++
 
 	var stk [maxCPUProfStack]uintptr
-	flags := uint(_TraceJumpStack)
 	n := 0
 	if mp.ncgo > 0 && mp.curg != nil && mp.curg.syscallpc != 0 && mp.curg.syscallsp != 0 {
 		cgoOff := 0
@@ -4689,12 +4688,12 @@ func sigprof(pc, sp, lr uintptr, gp *g, mp *m) {
 		}
 
 		// Collect Go stack that leads to the cgo call.
-		n = gentraceback(mp.curg.syscallpc, mp.curg.syscallsp, 0, mp.curg, 0, &stk[cgoOff], len(stk)-cgoOff, nil, nil, flags)
+		n = gentraceback(mp.curg.syscallpc, mp.curg.syscallsp, 0, mp.curg, 0, &stk[cgoOff], len(stk)-cgoOff, nil, nil, 0)
 		if n > 0 {
 			n += cgoOff
 		}
 	} else {
-		n = gentraceback(pc, sp, lr, gp, 0, &stk[0], len(stk), nil, nil, _TraceTrap|flags)
+		n = gentraceback(pc, sp, lr, gp, 0, &stk[0], len(stk), nil, nil, _TraceTrap|_TraceJumpStack)
 	}
 
 	if n <= 0 {
@@ -4704,10 +4703,10 @@ func sigprof(pc, sp, lr uintptr, gp *g, mp *m) {
 		if usesLibcall() && mp.libcallg != 0 && mp.libcallpc != 0 && mp.libcallsp != 0 {
 			// Libcall, i.e. runtime syscall on windows.
 			// Collect Go stack that leads to the call.
-			n = gentraceback(mp.libcallpc, mp.libcallsp, 0, mp.libcallg.ptr(), 0, &stk[0], len(stk), nil, nil, flags)
+			n = gentraceback(mp.libcallpc, mp.libcallsp, 0, mp.libcallg.ptr(), 0, &stk[0], len(stk), nil, nil, 0)
 		}
 		if n == 0 && mp != nil && mp.vdsoSP != 0 {
-			n = gentraceback(mp.vdsoPC, mp.vdsoSP, 0, gp, 0, &stk[0], len(stk), nil, nil, flags)
+			n = gentraceback(mp.vdsoPC, mp.vdsoSP, 0, gp, 0, &stk[0], len(stk), nil, nil, _TraceTrap|_TraceJumpStack)
 		}
 		if n == 0 {
 			// If all of the above has failed, account it against abstract "System" or "GC".