Re: [PATCH v3] kcov, usbip: collect coverage from vhci_rx_loop

On Mon, Oct 19, 2020 at 8:52 PM Shuah Khan [off-list ref] wrote:

On 10/19/20 12:49 PM, Shuah Khan wrote:

quoted

On 10/19/20 11:20 AM, Andrey Konovalov wrote:

quoted

From: Nazime Hande Harputluoglu <redacted>

Add kcov_remote_start()/kcov_remote_stop() annotations to the
vhci_rx_loop() function, which is responsible for parsing USB/IP packets
coming into USB/IP client.

Since vhci_rx_loop() threads are spawned per vhci_hcd device instance,
the
common kcov handle is used for kcov_remote_start()/stop() annotations
(see Documentation/dev-tools/kcov.rst for details). As the result kcov
can now be used to collect coverage from vhci_rx_loop() threads.

Signed-off-by: Nazime Hande Harputluoglu <redacted>
Signed-off-by: Andrey Konovalov <redacted>
---

Changes v2->v3:
- Fix build without KCOV enabled.

---
  drivers/usb/usbip/usbip_common.h | 4 ++++
  drivers/usb/usbip/vhci_rx.c      | 7 +++++++
  drivers/usb/usbip/vhci_sysfs.c   | 4 ++++
  3 files changed, 15 insertions(+)

diff --git a/drivers/usb/usbip/usbip_common.h

b/drivers/usb/usbip/usbip_common.h
index 8be857a4fa13..0906182011d6 100644

--- a/drivers/usb/usbip/usbip_common.h
+++ b/drivers/usb/usbip/usbip_common.h

@@ -277,6 +277,10 @@ struct usbip_device {
          void (*reset)(struct usbip_device *);
          void (*unusable)(struct usbip_device *);
      } eh_ops;
+
+#ifdef CONFIG_KCOV
+    u64 kcov_handle;
+#endif
  };
  #define kthread_get_run(threadfn, data, namefmt, ...)               \

diff --git a/drivers/usb/usbip/vhci_rx.c b/drivers/usb/usbip/vhci_rx.c
index 266024cbb64f..68ec0aa64f69 100644
--- a/drivers/usb/usbip/vhci_rx.c
+++ b/drivers/usb/usbip/vhci_rx.c

@@ -3,6 +3,7 @@
   * Copyright (C) 2003-2008 Takahiro Hirofuchi
   */
+#include <linux/kcov.h>
  #include <linux/kthread.h>
  #include <linux/slab.h>

@@ -261,7 +262,13 @@ int vhci_rx_loop(void *data)
          if (usbip_event_happened(ud))
              break;
+#ifdef CONFIG_KCOV
+        kcov_remote_start_common(ud->kcov_handle);
+#endif
          vhci_rx_pdu(ud);
+#ifdef CONFIG_KCOV
+        kcov_remote_stop();
+#endif
      }

Let's move these into usbip_common.h as inline functions along
the line of

#ifdef CONFIG_KCOV
usbip_kcov_remote_start_common(ud)
{
   kcov_remote_start_common(ud->kcov_handle);
}

usbip_kcov_remote_stop_common(ud)
{
   kcov_remote_stop_common(ud->kcov_handle);
}
#else
stubs that do nothing
#endif

Sounds good, will mail a new version shortly. Sorry for a delay, I was
busy with other work.

quoted

quoted

      return 0;

diff --git a/drivers/usb/usbip/vhci_sysfs.c

b/drivers/usb/usbip/vhci_sysfs.c
index be37aec250c2..e167b8a445ad 100644

--- a/drivers/usb/usbip/vhci_sysfs.c
+++ b/drivers/usb/usbip/vhci_sysfs.c

@@ -4,6 +4,7 @@
   * Copyright (C) 2015-2016 Nobuo Iwata
   */
+#include <linux/kcov.h>
  #include <linux/kthread.h>
  #include <linux/file.h>
  #include <linux/net.h>

@@ -383,6 +384,9 @@ static ssize_t attach_store(struct device *dev,

struct device_attribute *attr,
      vdev->ud.sockfd     = sockfd;
      vdev->ud.tcp_socket = socket;
      vdev->ud.status     = VDEV_ST_NOTASSIGNED;
+#ifdef CONFIG_KCOV
+    vdev->ud.kcov_handle = kcov_common_handle();
+#endif

Same here add a usbip_kcov_handle_init(ud)

btw - I am seeing bounces on handeharputlu@google.com address.

Hande is no longer at Google, so the email is no longer valid. I think
it makes sense to preserve the original email address in the patch.