From: Uwe Hermann <redacted>
Date: Thu, 9 Jul 2015 22:59:48 +0000 (+0200)
Subject: fx2lafw: Fix segfault wrt libusb_detach_kernel_driver().
X-Git-Tag: libsigrok-0.4.0~464
X-Git-Url: https://sigrok.org/gitaction?a=commitdiff_plain;h=dc2903bbdbc97d4d0968ffc23d475cf21adc8575;p=libsigrok.git

fx2lafw: Fix segfault wrt libusb_detach_kernel_driver().

Move the libusb_detach_kernel_driver() call after the code that
sets the usb->devhdl pointer, otherwise it'll be NULL and result
in a segfault.

  #0  libusb_kernel_driver_active (dev=0x0, interface_number=0) at libusb/core.c:1711
  #1  dev_open (sdi=0x12d99f0) at src/hardware/fx2lafw/api.c:374
  [...]

Tested on a device with the default Cypress VID/PID and one with
the Saleae Logic VID/PID, both works fine.
---

diff --git a/src/hardware/fx2lafw/api.c b/src/hardware/fx2lafw/api.c
index 724e2dd4..ada4fcc9 100644
--- a/src/hardware/fx2lafw/api.c
+++ b/src/hardware/fx2lafw/api.c
@@ -370,16 +370,6 @@ static int dev_open(struct sr_dev_inst *sdi)
 	devc = sdi->priv;
 	usb = sdi->conn;
 
-	if (libusb_has_capability(LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER)) {
-		if (libusb_kernel_driver_active(usb->devhdl, 0) == 1) {
-			if ((ret = libusb_detach_kernel_driver(usb->devhdl, 0)) < 0) {
-				sr_err("Failed to detach kernel driver: %s.",
-					libusb_error_name(ret));
-				return SR_ERR;
-			}
-		}
-	}
-
 	/*
 	 * If the firmware was recently uploaded, wait up to MAX_RENUM_DELAY_MS
 	 * milliseconds for the FX2 to renumerate.
diff --git a/src/hardware/fx2lafw/protocol.c b/src/hardware/fx2lafw/protocol.c
index 11e3504e..b1c20a71 100644
--- a/src/hardware/fx2lafw/protocol.c
+++ b/src/hardware/fx2lafw/protocol.c
@@ -244,6 +244,16 @@ SR_PRIV int fx2lafw_dev_open(struct sr_dev_inst *sdi, struct sr_dev_driver *di)
 			break;
 		}
 
+		if (libusb_has_capability(LIBUSB_CAP_SUPPORTS_DETACH_KERNEL_DRIVER)) {
+			if (libusb_kernel_driver_active(usb->devhdl, 0) == 1) {
+				if ((ret = libusb_detach_kernel_driver(usb->devhdl, 0)) < 0) {
+					sr_err("Failed to detach kernel driver: %s.",
+						libusb_error_name(ret));
+					return SR_ERR;
+				}
+			}
+		}
+
 		ret = command_get_fw_version(usb->devhdl, &vi);
 		if (ret != SR_OK) {
 			sr_err("Failed to get firmware version.");