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[PATCH 4.4 26/50] can: gs_usb: fixed disconnect bug by removing erroneous use of kfree()

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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Maximilain Schneider <max@schneidersoft.net>

commit e9a2d81b1761093386a0bb8a4f51642ac785ef63 upstream.

gs_destroy_candev() erroneously calls kfree() on a struct gs_can *, which is
allocated through alloc_candev() and should instead be freed using
free_candev() alone.

The inappropriate use of kfree() causes the kernel to hang when
gs_destroy_candev() is called.

Only the struct gs_usb * which is allocated through kzalloc() should be freed
using kfree() when the device is disconnected.

Signed-off-by: Maximilian Schneider <max@schneidersoft.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/can/usb/gs_usb.c |   24 +++++++++++-------------
 1 file changed, 11 insertions(+), 13 deletions(-)

--- a/drivers/net/can/usb/gs_usb.c
+++ b/drivers/net/can/usb/gs_usb.c
@@ -826,9 +826,8 @@ static struct gs_can *gs_make_candev(uns
 static void gs_destroy_candev(struct gs_can *dev)
 {
 	unregister_candev(dev->netdev);
-	free_candev(dev->netdev);
 	usb_kill_anchored_urbs(&dev->tx_submitted);
-	kfree(dev);
+	free_candev(dev->netdev);
 }
 
 static int gs_usb_probe(struct usb_interface *intf, const struct usb_device_id *id)
@@ -913,12 +912,15 @@ static int gs_usb_probe(struct usb_inter
 	for (i = 0; i < icount; i++) {
 		dev->canch[i] = gs_make_candev(i, intf);
 		if (IS_ERR_OR_NULL(dev->canch[i])) {
+			/* save error code to return later */
+			rc = PTR_ERR(dev->canch[i]);
+
 			/* on failure destroy previously created candevs */
 			icount = i;
-			for (i = 0; i < icount; i++) {
+			for (i = 0; i < icount; i++)
 				gs_destroy_candev(dev->canch[i]);
-				dev->canch[i] = NULL;
-			}
+
+			usb_kill_anchored_urbs(&dev->rx_submitted);
 			kfree(dev);
 			return rc;
 		}
@@ -939,16 +941,12 @@ static void gs_usb_disconnect(struct usb
 		return;
 	}
 
-	for (i = 0; i < GS_MAX_INTF; i++) {
-		struct gs_can *can = dev->canch[i];
-
-		if (!can)
-			continue;
-
-		gs_destroy_candev(can);
-	}
+	for (i = 0; i < GS_MAX_INTF; i++)
+		if (dev->canch[i])
+			gs_destroy_candev(dev->canch[i]);
 
 	usb_kill_anchored_urbs(&dev->rx_submitted);
+	kfree(dev);
 }
 
 static const struct usb_device_id gs_usb_table[] = {

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[PATCH 4.4 00/50] 4.4.6-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100
  [PATCH 4.4 11/50] KVM: MMU: fix reserved bit check for ept=0/CR0.WP=0/CR4.SMEP=1/EFER.NX=0 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100
  [PATCH 4.4 47/50] MIPS: smp.c: Fix uninitialised temp_foreign_map Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100
  [PATCH 4.4 10/50] KVM: MMU: fix ept=0/pte.u=1/pte.w=0/CR0.WP=0/CR4.SMEP=1/EFER.NX=0 combo Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100
  [PATCH 4.4 14/50] tracing: Fix check for cpu online when event is disabled Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:10 +0100
  [PATCH 4.4 39/50] Revert "drm/radeon/pm: adjust display configuration after powerstate" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 30/50] mac80211: minstrel_ht: set default tx aggregation timeout to 0 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 21/50] ASoC: wm8958: Fix enum ctl accesses in a wrong type Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 27/50] iwlwifi: mvm: inc pending frames counter also when txing non-sta Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 43/50] userfaultfd: dont block on the last VM updates at exit time Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 32/50] mac80211: check PN correctly for GCMP-encrypted fragmented MPDUs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 26/50] can: gs_usb: fixed disconnect bug by removing erroneous use of kfree() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 40/50] powerpc: Fix dedotify for binutils >= 2.26 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 28/50] mac80211: minstrel: Change expected throughput unit back to Kbps Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 33/50] mac80211: Fix Public Action frame RX in AP mode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 41/50] powerpc/powernv: Add a kmsg_dumper that flushes console output on panic Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 29/50] mac80211: fix use of uninitialised values in RX aggregation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 22/50] ovl: ignore lower entries when checking purity of non-directory entries Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 04/50] ARM: OMAP2+: hwmod: Introduce ti,no-idle dt property Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 45/50] ovl: fix getcwd() failure after unsuccessful rmdir Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 23/50] ovl: fix working on distributed fs as lower layer Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 03/50] ARM: dts: dra7: do not gate cpsw clock due to errata i877 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 02/50] ARM: mvebu: fix overlap of Crypto SRAM with PCIe memory window Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 24/50] wext: fix message delay/ordering Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 06/50] kvm: cap halt polling at exactly halt_poll_ns Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 44/50] ovl: copy new uid/gid into overlayfs runtime inode Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 35/50] x86/mm: Fix slow_virt_to_phys() for X86_PAE again Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 42/50] powerpc/powernv: Fix OPAL_CONSOLE_FLUSH prototype and usages Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 34/50] gpu: ipu-v3: Do not bail out on missing optional port nodes Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:20 +0100
  [PATCH 4.4 15/50] dmaengine: at_xdmac: fix residue computation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:30 +0100
  [PATCH 4.4 25/50] cfg80211/wext: fix message ordering Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:30 +0100
  [PATCH 4.4 20/50] ASoC: wm8994: Fix enum ctl accesses in a wrong type Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:30 +0100
  [PATCH 4.4 19/50] ASoC: samsung: Use IRQ safe spin lock calls Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-14 19:30 +0100
  Re: [PATCH 4.4 00/50] 4.4.6-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2016-03-15 00:20 +0100
    Re: [PATCH 4.4 00/50] 4.4.6-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-16 16:50 +0100
  Re: [PATCH 4.4 00/50] 4.4.6-stable review Guenter Roeck <linux@roeck-us.net> - 2016-03-15 03:40 +0100
    Re: [PATCH 4.4 00/50] 4.4.6-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-03-16 16:50 +0100

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