// Find the var's defining block in the CFG,
	// plus the rest of the statements of that block.
	var defblock *cfg.Block
	var rest []ast.Node
outer:
	for _, b := range g.Blocks {
		for i, n := range b.Nodes {
			if n == stmt {
				defblock = b
				rest = b.Nodes[i+1:]
				break outer
			}
		}
	}
	if defblock == nil {
		panic("internal error: can't find defining block for cancel var")
	}

				}
			}
		}
		for _, ctl := range block.ControlValues() {
			// for control values that can become constants, find their use blocks
			if possibleConst(ctl) {
				t.defBlock[ctl] = append(t.defBlock[ctl], block)
			}
		}
	}
}

// addUses finds all uses of value and appends them into work list for further process
func (t *worklist) addUses(val *Value) {
	for _, use := range t.defUse[val] {

import "C"
import (
	"fmt"
)

func init() {
	register("CgoPanicDeadlock", CgoPanicDeadlock)
}

type cgoError struct{}

func (cgoError) Error() string {
	fmt.Print("") // necessary to trigger the deadlock
	return C.GoString(C.geterror())
}

func CgoPanicDeadlock() {
	panic(cgoError{})

Dan Scales <******@****.***> 1611625863 -0800

John Howard <******@****.***> 1654795350 -0700

//go:build !plan9 && !windows
// +build !plan9,!windows

package main

// This is for issue #42207.
// During a call to needm we could get a SIGCHLD signal
// which would itself call needm, causing a deadlock.

/*
#include <signal.h>
#include <pthread.h>
#include <sched.h>
#include <unistd.h>

extern void GoNeedM();

#define SIGNALERS 10

static void* needmSignalThread(void* p) {

 *       "safe" edge is created.
 *   <li>If a cycle is detected, an "unsafe" (cyclic) edge is created to represent a potential
 *       deadlock situation, and the appropriate Policy is executed.
 * </ul>
 *
 * <p>Note that detection of potential deadlock does not necessarily indicate that deadlock will
 * happen, as it is possible that higher level application logic prevents the cyclic lock

! go test -fuzz=FuzzDead -v
# This is a somewhat inexact check, but since we don't prefix the error with anything
# and as the error suffix is platform dependent, this is the best we can do. In the
# deadlock failure case, the test will just deadlock and timeout anyway, so it should
# be clear that that failure mode is different.
stdout 'open'

-- go.mod --
module test

-- cov_test.go --
package dead

import (
	"os"

	mu.Unlock()

	if wait != nil {
		wait <- f
	}

	// Spurious EDEADLK errors arise on platforms that compute deadlock graphs at
	// the process, rather than thread, level. Consider processes P and Q, with
	// threads P.1, P.2, and Q.3. The following trace is NOT a deadlock, but will be
	// reported as a deadlock on systems that consider only process granularity:
	//
	// 	P.1 locks file A.
	// 	Q.3 locks file B.

 *       "safe" edge is created.
 *   <li>If a cycle is detected, an "unsafe" (cyclic) edge is created to represent a potential
 *       deadlock situation, and the appropriate Policy is executed.
 * </ul>
 *
 * <p>Note that detection of potential deadlock does not necessarily indicate that deadlock will
 * happen, as it is possible that higher level application logic prevents the cyclic lock