Re: [PATCH v2 3/3] usb: core: kcov: collect coverage from usb complete callback

On Thu, Mar 12, 2020 at 10:39 AM Peter Chen [off-list ref] wrote:

On 20-03-09 19:27:06, Andrey Konovalov wrote:

quoted

This patch adds kcov_remote_start/stop() callbacks around the urb
complete() callback that is executed in softirq context when dummy_hcd
is in use. As the result, kcov can be used to collect coverage from those
those callbacks, which is used to facilitate coverage-guided fuzzing with

Typo, One more "those"

Will fix in v3, thanks Peter!

Peter

quoted

syzkaller.

Signed-off-by: Andrey Konovalov <redacted>
---
 drivers/usb/core/hcd.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index aa45840d8273..de624c47e190 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c

@@ -31,6 +31,7 @@
 #include <linux/types.h>
 #include <linux/genalloc.h>
 #include <linux/io.h>
+#include <linux/kcov.h>

 #include <linux/phy/phy.h>
 #include <linux/usb.h>

@@ -1645,7 +1646,9 @@ static void __usb_hcd_giveback_urb(struct urb *urb)

      /* pass ownership to the completion handler */
      urb->status = status;
+     kcov_remote_start_usb((u64)urb->dev->bus->busnum);
      urb->complete(urb);
+     kcov_remote_stop();

      usb_anchor_resume_wakeups(anchor);
      atomic_dec(&urb->use_count);
--

2.25.1.481.gfbce0eb801-goog

--

Thanks,
Peter Chen