diff --git a/tools/testing/ktest/ktest.pl b/tools/testing/ktest/ktest.pl
index 79da57f..a34f6f4 100644
--- a/tools/testing/ktest/ktest.pl
+++ b/tools/testing/ktest/ktest.pl
@@ -25,11 +25,13 @@
 $opt{"BUILD_OPTIONS"}		= "";
 
 my $version;
-my $install_mods;
 my $grub_number;
 my $target;
 my $make;
 my $noclean;
+my $minconfig;
+my $in_bisect = 0;
+my $bisect_bad = "";
 
 sub read_config {
     my ($config) = @_;
@@ -52,9 +54,7 @@
     close(IN);
 }
 
-sub doprint {
-    print @_;
-
+sub logit {
     if (defined($opt{"LOG_FILE"})) {
 	open(OUT, ">> $opt{LOG_FILE}") or die "Can't write to $opt{LOG_FILE}";
 	print OUT @_;
@@ -62,6 +62,11 @@
     }
 }
 
+sub doprint {
+    print @_;
+    logit @_;
+}
+
 sub dodie {
     doprint "CRITICAL FAILURE... ", @_;
 
@@ -96,7 +101,30 @@
 	doprint "SUCCESS\n";
     }
 
-    return $failed;
+    return !$failed;
+}
+
+sub get_grub_index {
+
+    return if ($grub_number >= 0);
+
+    doprint "Find grub menu ... ";
+    $grub_number = -1;
+    open(IN, "ssh $target cat /boot/grub/menu.lst |")
+	or die "unable to get menu.lst";
+    while (<IN>) {
+	if (/^\s*title\s+$opt{GRUB_MENU}\s*$/) {
+	    $grub_number++;
+	    last;
+	} elsif (/^\s*title\s/) {
+	    $grub_number++;
+	}
+    }
+    close(IN);
+
+    die "Could not find '$opt{GRUB_MENU}' in /boot/grub/menu on $opt{MACHINE}"
+	if ($grub_number < 0);
+    doprint "$grub_number\n";
 }
 
 my $timeout = $opt{"TIMEOUT"};
@@ -213,46 +241,63 @@
     close(IN);
 
     if (!$booted) {
+	return 1 if (!$in_bisect);
 	dodie "failed - never got a boot prompt.\n";
     }
 
     if ($bug) {
+	return 1 if (!$in_bisect);
 	dodie "failed - got a bug report\n";
     }
+
+    return 0;
 }
 
 sub install {
 
-    if (run_command "scp $opt{OUTPUT_DIR}/$opt{BUILD_TARGET} $target:$opt{TARGET_IMAGE}") {
+    run_command "scp $opt{OUTPUT_DIR}/$opt{BUILD_TARGET} $target:$opt{TARGET_IMAGE}" or
 	dodie "failed to copy image";
+
+    my $install_mods = 0;
+
+    # should we process modules?
+    $install_mods = 0;
+    open(IN, "$opt{OUTPUT_DIR}/.config") or dodie("Can't read config file");
+    while (<IN>) {
+	if (/CONFIG_MODULES(=y)?/) {
+	    $install_mods = 1 if (defined($1));
+	    last;
+	}
+    }
+    close(IN);
+
+    if (!$install_mods) {
+	doprint "No modules needed\n";
+	return;
     }
 
-    if ($install_mods) {
-	my $modlib = "/lib/modules/$version";
-	my $modtar = "autotest-mods.tar.bz2";
+    run_command "$make INSTALL_MOD_PATH=$opt{TMP_DIR} modules_install" or
+	dodie "Failed to install modules";
 
-	if (run_command "ssh $target rm -rf $modlib") {
-	    dodie "failed to remove old mods: $modlib";
-	}
+    my $modlib = "/lib/modules/$version";
+    my $modtar = "autotest-mods.tar.bz2";
 
-	# would be nice if scp -r did not follow symbolic links
-	if (run_command "cd $opt{TMP_DIR} && tar -cjf $modtar lib/modules/$version") {
-	    dodie "making tarball";
-	}
+    run_command "ssh $target rm -rf $modlib" or
+	dodie "failed to remove old mods: $modlib";
 
-	if (run_command "scp $opt{TMP_DIR}/$modtar $target:/tmp") {
-	    dodie "failed to copy modules";
-	}
+    # would be nice if scp -r did not follow symbolic links
+    run_command "cd $opt{TMP_DIR} && tar -cjf $modtar lib/modules/$version" or
+	dodie "making tarball";
 
-	unlink "$opt{TMP_DIR}/$modtar";
+    run_command "scp $opt{TMP_DIR}/$modtar $target:/tmp" or
+	dodie "failed to copy modules";
 
-	if (run_command "ssh $target '(cd / && tar xf /tmp/$modtar)'") {
-	    dodie "failed to tar modules";
-	}
+    unlink "$opt{TMP_DIR}/$modtar";
 
-	run_command "ssh $target rm -f /tmp/$modtar";
-    }
+    run_command "ssh $target '(cd / && tar xf /tmp/$modtar)'" or
+	dodie "failed to tar modules";
 
+    run_command "ssh $target rm -f /tmp/$modtar";
 }
 
 sub build {
@@ -261,9 +306,9 @@
     my $append = "";
 
     if ($type =~ /^useconfig:(.*)/) {
-	if (run_command "cp $1 $opt{OUTPUT_DIR}/.config") {
+	run_command "cp $1 $opt{OUTPUT_DIR}/.config" or
 	    dodie "could not copy $1 to .config";
-	}
+
 	$type = "oldconfig";
     }
 
@@ -274,23 +319,20 @@
 	# allow for empty configs
 	run_command "touch $opt{OUTPUT_DIR}/.config";
 
-	if (run_command "mv $opt{OUTPUT_DIR}/.config $opt{OUTPUT_DIR}/config_temp") {
+	run_command "mv $opt{OUTPUT_DIR}/.config $opt{OUTPUT_DIR}/config_temp" or
 	    dodie "moving .config";
-	}
 
-	if (!$noclean && run_command "$make mrproper") {
+	if (!$noclean && !run_command "$make mrproper") {
 	    dodie "make mrproper";
 	}
 
-	if (run_command "mv $opt{OUTPUT_DIR}/config_temp $opt{OUTPUT_DIR}/.config") {
+	run_command "mv $opt{OUTPUT_DIR}/config_temp $opt{OUTPUT_DIR}/.config" or
 	    dodie "moving config_temp";
-	}
 
     } elsif (!$noclean) {
 	unlink "$opt{OUTPUT_DIR}/.config";
-	if (run_command "$make mrproper") {
+	run_command "$make mrproper" or
 	    dodie "make mrproper";
-	}
     }
 
     # add something to distinguish this build
@@ -298,34 +340,162 @@
     print OUT "$opt{LOCALVERSION}\n";
     close(OUT);
 
-    if (defined($opt{"MIN_CONFIG"})) {
-	$defconfig = "KCONFIG_ALLCONFIG=$opt{MIN_CONFIG}";
+    if (defined($minconfig)) {
+	$defconfig = "KCONFIG_ALLCONFIG=$minconfig";
     }
 
-    if (run_command "$defconfig $append $make $type") {
+    run_command "$defconfig $append $make $type" or
 	dodie "failed make config";
-    }
 
-    if (run_command "$make $opt{BUILD_OPTIONS}") {
+    if (!run_command "$make $opt{BUILD_OPTIONS}") {
+	# bisect may need this to pass
+	return 1 if ($in_bisect);
 	dodie "failed build";
     }
+
+    return 0;
 }
 
 sub reboot {
     # try to reboot normally
-    if (run_command "ssh $target reboot") {
+    if (!run_command "ssh $target reboot") {
 	# nope? power cycle it.
 	run_command "$opt{POWER_CYCLE}";
     }
 }
 
 sub halt {
-    if ((run_command "ssh $target halt") or defined($opt{"POWER_OFF"})) {
+    if (!run_command "ssh $target halt" or defined($opt{"POWER_OFF"})) {
 	# nope? the zap it!
 	run_command "$opt{POWER_OFF}";
     }
 }
 
+sub success {
+    my ($i) = @_;
+
+    doprint "\n\n*******************************************\n";
+    doprint     "*******************************************\n";
+    doprint     "**            SUCCESS!!!!                **\n";
+    doprint     "*******************************************\n";
+    doprint     "*******************************************\n";
+
+    if ($i != $opt{"NUM_BUILDS"}) {
+	reboot;
+	doprint "Sleeping $opt{SLEEP_TIME} seconds\n";
+	sleep "$opt{SLEEP_TIME}";
+    }
+}
+
+sub get_version {
+    # get the release name
+    doprint "$make kernelrelease ... ";
+    $version = `$make kernelrelease | tail -1`;
+    chomp($version);
+    doprint "$version\n";
+}
+
+sub run_bisect {
+    my ($type) = @_;
+
+    my $failed;
+    my $result;
+    my $output;
+    my $ret;
+
+
+    if (defined($minconfig)) {
+	$failed = build "useconfig:$minconfig";
+    } else {
+	# ?? no config to use?
+	$failed = build "oldconfig";
+    }
+
+    if ($type ne "build") {
+	dodie "Failed on build" if $failed;
+
+	# Now boot the box
+	get_grub_index;
+	get_version;
+	install;
+	$failed = monitor;
+
+	if ($type ne "boot") {
+	    dodie "Failed on boot" if $failed;
+	}
+    }
+
+    if ($failed) {
+	$result = "bad";
+    } else {
+	$result = "good";
+    }
+
+    doprint "git bisect $result ... ";
+    $output = `git bisect $result 2>&1`;
+    $ret = $?;
+
+    logit $output;
+
+    if ($ret) {
+	doprint "FAILED\n";
+	dodie "Failed to git bisect";
+    }
+
+    doprint "SUCCESS\n";
+    if ($output =~ m/^(Bisecting: .*\(roughly \d+ steps?\)) \[([[:xdigit:]]+)\]/) {
+	doprint "$1 [$2]\n";
+    } elsif ($output =~ m/^([[:xdigit:]]+) is the first bad commit/) {
+	$bisect_bad = $1;
+	doprint "Found bad commit... $1\n";
+	return 0;
+    }
+
+
+    return 1;
+}
+
+sub bisect {
+    my ($i) = @_;
+
+    my $result;
+
+    die "BISECT_GOOD[$i] not defined\n"	if (!defined($opt{"BISECT_GOOD[$i]"}));
+    die "BISECT_BAD[$i] not defined\n"	if (!defined($opt{"BISECT_BAD[$i]"}));
+    die "BISECT_TYPE[$i] not defined\n"	if (!defined($opt{"BISECT_TYPE[$i]"}));
+
+    my $good = $opt{"BISECT_GOOD[$i]"};
+    my $bad = $opt{"BISECT_BAD[$i]"};
+    my $type = $opt{"BISECT_TYPE[$i]"};
+
+    $in_bisect = 1;
+
+    run_command "git bisect start" or
+	dodie "could not start bisect";
+
+    run_command "git bisect good $good" or
+	dodie "could not set bisect good to $good";
+
+    run_command "git bisect bad $bad" or
+	dodie "could not set bisect good to $bad";
+
+    do {
+	$result = run_bisect $type;
+    } while ($result);
+
+    run_command "git bisect log" or
+	dodie "could not capture git bisect log";
+
+    run_command "git bisect reset" or
+	dodie "could not reset git bisect";
+
+    doprint "Bad commit was [$bisect_bad]\n";
+
+    $in_bisect = 0;
+
+    success $i;
+}
+
 read_config $ARGV[0];
 
 # mandatory configs
@@ -346,22 +516,6 @@
 
 doprint "\n\nSTARTING AUTOMATED TESTS\n";
 
-doprint "Find grub menu ... ";
-$grub_number = -1;
-open(IN, "ssh $target cat /boot/grub/menu.lst |")
-    or die "unable to get menu.lst";
-while (<IN>) {
-    if (/^\s*title\s+$opt{GRUB_MENU}\s*$/) {
-	$grub_number++;
-	last;
-    } elsif (/^\s*title\s/) {
-	$grub_number++;
-    }
-}
-close(IN);
-die "Could not find '$opt{GRUB_MENU}' in /boot/grub/menu on $opt{MACHINE}"
-    if ($grub_number < 0);
-doprint "$grub_number\n";
 
 $make = "$opt{MAKE_CMD} O=$opt{OUTPUT_DIR}";
 
@@ -376,6 +530,14 @@
 	$noclean = $opt{"BUILD_NOCLEAN"};
     }
 
+    if (defined($opt{"MIN_CONFIG[$i]"})) {
+	$minconfig = $opt{"MIN_CONFIG[$i]"};
+    } elsif (defined($opt{"MIN_CONFIG"})) {
+	$minconfig = $opt{"MIN_CONFIG"};
+    } else {
+	undef $minconfig;
+    }
+
     if (!defined($opt{$type})) {
 	$opt{$type} = $opt{"DEFAULT_BUILD_TYPE"};
     }
@@ -383,49 +545,20 @@
     doprint "\n\n";
     doprint "RUNNING TEST $i of $opt{NUM_BUILDS} with option $opt{$type}\n\n";
 
+    if ($opt{$type} eq "bisect") {
+	bisect $i;
+	next;
+    }
+
     if ($opt{$type} ne "nobuild") {
 	build $opt{$type};
     }
 
-    # get the release name
-    doprint "$make kernelrelease ... ";
-    $version = `$make kernelrelease | tail -1`;
-    chomp($version);
-    doprint "$version\n";
-
-    # should we process modules?
-    $install_mods = 0;
-    open(IN, "$opt{OUTPUT_DIR}/.config") or dodie("Can't read config file");
-    while (<IN>) {
-	if (/CONFIG_MODULES(=y)?/) {
-	    $install_mods = 1 if (defined($1));
-	    last;
-	}
-    }
-    close(IN);
-
-    if ($install_mods) {
-	if (run_command "$make INSTALL_MOD_PATH=$opt{TMP_DIR} modules_install") {
-	    dodie "Failed to install modules";
-	}
-    } else {
-	doprint "No modules needed\n";
-    }
-
+    get_grub_index;
+    get_version;
     install;
-
     monitor;
-
-    doprint "\n\n*******************************************\n";
-    doprint     "*******************************************\n";
-    doprint     "**            SUCCESS!!!!                **\n";
-    doprint     "*******************************************\n";
-    doprint     "*******************************************\n";
-
-    if ($i != $opt{"NUM_BUILDS"}) {
-	reboot;
-	sleep "$opt{SLEEP_TIME}";
-    }
+    success $i;
 }
 
 if ($opt{"POWEROFF_ON_SUCCESS"}) {