From fd8caa5462e64f37cb9eebd75ffca1737dde447d Mon Sep 17 00:00:00 2001
From: Aleksandr Nogikh <nogikh@google.com>
Date: Thu, 23 Sep 2021 16:15:41 +0000
Subject: all: replace collide mode by `async` call property

Replace the currently existing straightforward approach to race triggering
(that was almost entirely implemented inside syz-executor) with a more
flexible one.

The `async` call property instructs syz-executor not to block until the
call has completed execution and proceed immediately to the next call.
The decision on what calls to mark with `async` is made by syz-fuzzer.

Ultimately this should let us implement more intelligent race provoking
strategies as well as make more fine-grained reproducers.
---
 tools/syz-execprog/execprog.go   | 16 ++++++++++++++++
 tools/syz-prog2c/prog2c.go       |  2 --
 tools/syz-reprolist/reprolist.go |  4 +++-
 3 files changed, 19 insertions(+), 3 deletions(-)

(limited to 'tools')

diff --git a/tools/syz-execprog/execprog.go b/tools/syz-execprog/execprog.go
index 6c69e0ff6..d22b5a0bf 100644
--- a/tools/syz-execprog/execprog.go
+++ b/tools/syz-execprog/execprog.go
@@ -38,6 +38,19 @@ var (
 	flagHints     = flag.Bool("hints", false, "do a hints-generation run")
 	flagEnable    = flag.String("enable", "none", "enable only listed additional features")
 	flagDisable   = flag.String("disable", "none", "enable all additional features except listed")
+	// The following flag is only kept to let syzkaller remain compatible with older execprog versions.
+	// In order to test incoming patches or perform bug bisection, syz-ci must use the exact syzkaller
+	// version that detected the bug (as descriptions and syntax could've already been changed), and
+	// therefore it must be able to invoke older versions of syz-execprog.
+	// Unfortunately there's no clean way to drop that flag from newer versions of syz-execprog. If it
+	// were false by default, it would be easy - we could modify `instance.ExecprogCmd` only to pass it
+	// when it's true - which would never be the case in the newer versions (this is how we got rid of
+	// fault injection args). But the collide flag was true by default, so it must be passed by value
+	// (-collide=%v). The least kludgy solution is to silently accept this flag also in the newer versions
+	// of syzkaller, but do not process it, as there's no such functionality anymore.
+	// Note, however, that we do not have to do the same for `syz-prog2c`, as `collide` was there false
+	// by default.
+	flagCollide = flag.Bool("collide", false, "(DEPRECATED) collide syscalls to provoke data races")
 )
 
 func main() {
@@ -73,6 +86,9 @@ func main() {
 			log.Logf(0, "%-24v: %v", feat.Name, feat.Reason)
 		}
 	}
+	if *flagCollide {
+		log.Fatalf("setting -collide to true is deprecated now")
+	}
 	config, execOpts := createConfig(target, features, featuresFlags)
 	if err = host.Setup(target, features, featuresFlags, config.Executor); err != nil {
 		log.Fatal(err)
diff --git a/tools/syz-prog2c/prog2c.go b/tools/syz-prog2c/prog2c.go
index aa9c146e1..7cea629f8 100644
--- a/tools/syz-prog2c/prog2c.go
+++ b/tools/syz-prog2c/prog2c.go
@@ -21,7 +21,6 @@ var (
 	flagArch       = flag.String("arch", runtime.GOARCH, "target arch")
 	flagBuild      = flag.Bool("build", false, "also build the generated program")
 	flagThreaded   = flag.Bool("threaded", false, "create threaded program")
-	flagCollide    = flag.Bool("collide", false, "create collide program")
 	flagRepeat     = flag.Int("repeat", 1, "repeat program that many times (<=0 - infinitely)")
 	flagProcs      = flag.Int("procs", 1, "number of parallel processes")
 	flagSlowdown   = flag.Int("slowdown", 1, "execution slowdown caused by emulation/instrumentation")
@@ -72,7 +71,6 @@ func main() {
 	}
 	opts := csource.Options{
 		Threaded:      *flagThreaded,
-		Collide:       *flagCollide,
 		Repeat:        *flagRepeat != 1,
 		RepeatTimes:   *flagRepeat,
 		Procs:         *flagProcs,
diff --git a/tools/syz-reprolist/reprolist.go b/tools/syz-reprolist/reprolist.go
index 0833a8593..a14740d05 100644
--- a/tools/syz-reprolist/reprolist.go
+++ b/tools/syz-reprolist/reprolist.go
@@ -177,9 +177,11 @@ func createProg2CArgs(bug *dashapi.BugReport, opts csource.Options, file string)
 		"-prog", file,
 		"-sandbox", opts.Sandbox,
 		fmt.Sprintf("-segv=%v", opts.HandleSegv),
-		fmt.Sprintf("-collide=%v", opts.Collide),
 		fmt.Sprintf("-threaded=%v", opts.Threaded),
 	}
+	if opts.Collide {
+		args = append(args, "-collide")
+	}
 	if haveOSFlag {
 		args = append(args, "-os", *flagOS)
 	}
-- 
cgit mrf-deployment