[syzbot] memory leak in mld_newpack

[syzbot] memory leak in mld_newpack

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    8cae8cd89f05 seq_file: disallow extremely large seq buffer..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1100e00a300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7384ed231a0fd986
dashboard link: https://syzkaller.appspot.com/bug?extid=dcd3e13cf4472f2e0ba1
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14c646a2300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dcd3e13cf4472f2e0ba1@syzkaller.appspotmail.com

2021/07/22 00:14:37 executed programs: 3
2021/07/22 00:14:42 executed programs: 5
2021/07/22 00:14:48 executed programs: 7
BUG: memory leak
unreferenced object 0xffff88810df2ad00 (size 232):
  comm "kworker/1:2", pid 2838, jiffies 4294938475 (age 902.280s)
  hex dump (first 32 bytes):
    a0 34 1f 19 81 88 ff ff a0 34 1f 19 81 88 ff ff  .4.......4......
    00 40 1c 10 81 88 ff ff 00 00 00 00 00 00 00 00  .@..............
  backtrace:
    [<ffffffff836e0f5f>] __alloc_skb+0x20f/0x280 net/core/skbuff.c:414
    [<ffffffff836eb79a>] alloc_skb include/linux/skbuff.h:1112 [inline]
    [<ffffffff836eb79a>] alloc_skb_with_frags+0x6a/0x2b0 net/core/skbuff.c:6005
    [<ffffffff836d9083>] sock_alloc_send_pskb+0x353/0x3c0 net/core/sock.c:2461
    [<ffffffff83b7fd64>] mld_newpack+0x84/0x200 net/ipv6/mcast.c:1751
    [<ffffffff83b7ff83>] add_grhead+0xa3/0xc0 net/ipv6/mcast.c:1854
    [<ffffffff83b80c26>] add_grec+0x7b6/0x820 net/ipv6/mcast.c:1992
    [<ffffffff83b830d3>] mld_send_cr net/ipv6/mcast.c:2118 [inline]
    [<ffffffff83b830d3>] mld_ifc_work+0x273/0x750 net/ipv6/mcast.c:2655
    [<ffffffff81262669>] process_one_work+0x2c9/0x610 kernel/workqueue.c:2276
    [<ffffffff81262f59>] worker_thread+0x59/0x5d0 kernel/workqueue.c:2422
    [<ffffffff8126c3b8>] kthread+0x188/0x1d0 kernel/kthread.c:319
    [<ffffffff810022cf>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295

BUG: memory leak
unreferenced object 0xffff88811109ca00 (size 232):
  comm "kworker/1:2", pid 2838, jiffies 4294938656 (age 900.470s)
  hex dump (first 32 bytes):
    a0 ac 9e 16 81 88 ff ff a0 ac 9e 16 81 88 ff ff  ................
    00 00 37 13 81 88 ff ff 00 00 00 00 00 00 00 00  ..7.............
  backtrace:
    [<ffffffff836e0f5f>] __alloc_skb+0x20f/0x280 net/core/skbuff.c:414
    [<ffffffff83b6bb36>] alloc_skb include/linux/skbuff.h:1112 [inline]
    [<ffffffff83b6bb36>] ndisc_alloc_skb+0x56/0xe0 net/ipv6/ndisc.c:420
    [<ffffffff83b7085c>] ndisc_send_rs+0x1bc/0x2a0 net/ipv6/ndisc.c:686
    [<ffffffff83b46bae>] addrconf_dad_completed+0x17e/0x560 net/ipv6/addrconf.c:4195
    [<ffffffff83b4736d>] addrconf_dad_work+0x3dd/0x900 net/ipv6/addrconf.c:4105
    [<ffffffff81262669>] process_one_work+0x2c9/0x610 kernel/workqueue.c:2276
    [<ffffffff81262f59>] worker_thread+0x59/0x5d0 kernel/workqueue.c:2422
    [<ffffffff8126c3b8>] kthread+0x188/0x1d0 kernel/kthread.c:319
    [<ffffffff810022cf>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295



---
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Re: [syzbot] memory leak in mld_newpack

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    6879c2d3b960 Merge tag 'pinctrl-v6.0-2' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1053435d080000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a4afe4efcad47dde
dashboard link: https://syzkaller.appspot.com/bug?extid=dcd3e13cf4472f2e0ba1
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11842b37080000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15078ed5080000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/0e68bb9c6cf9/disk-6879c2d3.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/bf179217db31/vmlinux-6879c2d3.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+dcd3e13cf4472f2e0ba1@syzkaller.appspotmail.com

BUG: memory leak
unreferenced object 0xffff88810bb0bb00 (size 240):
  comm "kworker/0:2", pid 143, jiffies 4294946271 (age 15.640s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 bb b0 0b 81 88 ff ff  ................
    00 70 aa 11 81 88 ff ff 80 10 e9 44 81 88 ff ff  .p.........D....
  backtrace:
    [<ffffffff8387bb59>] __alloc_skb+0x1f9/0x270 net/core/skbuff.c:422
    [<ffffffff8388255a>] alloc_skb include/linux/skbuff.h:1257 [inline]
    [<ffffffff8388255a>] alloc_skb_with_frags+0x6a/0x340 net/core/skbuff.c:6021
    [<ffffffff8387508f>] sock_alloc_send_pskb+0x39f/0x3d0 net/core/sock.c:2665
    [<ffffffff83d4eb01>] sock_alloc_send_skb include/net/sock.h:1866 [inline]
    [<ffffffff83d4eb01>] mld_newpack.isra.0+0x81/0x200 net/ipv6/mcast.c:1748
    [<ffffffff83d4ed26>] add_grhead+0xa6/0xc0 net/ipv6/mcast.c:1851
    [<ffffffff83d4f4fc>] add_grec+0x7bc/0x820 net/ipv6/mcast.c:1989
    [<ffffffff83d514e3>] mld_send_cr net/ipv6/mcast.c:2115 [inline]
    [<ffffffff83d514e3>] mld_ifc_work+0x273/0x750 net/ipv6/mcast.c:2653
    [<ffffffff8127afca>] process_one_work+0x2ba/0x5f0 kernel/workqueue.c:2289
    [<ffffffff8127b8e9>] worker_thread+0x59/0x5b0 kernel/workqueue.c:2436
    [<ffffffff81284c95>] kthread+0x125/0x160 kernel/kthread.c:376
    [<ffffffff8100224f>] ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

[PATCH net] usbnet: Fix memory leak in usbnet_disconnect()

[Peilin Ye]

From: Peilin Ye <peilin.ye@bytedance.com>

Currently usbnet_disconnect() unanchors and frees all deferred URBs
using usb_scuttle_anchored_urbs(), which does not free urb->context,
causing a memory leak as reported by syzbot.

Use a usb_get_from_anchor() while loop instead, similar to what we did
in commit 19cfe912c37b ("Bluetooth: btusb: Fix memory leak in
play_deferred").  Also free urb->sg.

Reported-and-tested-by: syzbot+dcd3e13cf4472f2e0ba1@syzkaller.appspotmail.com
Fixes: 69ee472f2706 ("usbnet & cdc-ether: Autosuspend for online devices")
Fixes: 638c5115a794 ("USBNET: support DMA SG")
Signed-off-by: Peilin Ye <peilin.ye@bytedance.com>
---
Hi all,

I think we may have similar issues at other usb_scuttle_anchored_urbs()
call sites.  Since urb->context is (void *), should we pass a "destructor"
callback to usb_scuttle_anchored_urbs(), or replace this function with
usb_get_from_anchor() loops like this patch does?

Please advise, thanks!
Peilin Ye

 drivers/net/usb/usbnet.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index fd399a8ed973..64a9a80b2309 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -1598,6 +1598,7 @@ void usbnet_disconnect (struct usb_interface *intf)
 	struct usbnet		*dev;
 	struct usb_device	*xdev;
 	struct net_device	*net;
+	struct urb		*urb;
 
 	dev = usb_get_intfdata(intf);
 	usb_set_intfdata(intf, NULL);
@@ -1614,7 +1615,11 @@ void usbnet_disconnect (struct usb_interface *intf)
 	net = dev->net;
 	unregister_netdev (net);
 
-	usb_scuttle_anchored_urbs(&dev->deferred);
+	while ((urb = usb_get_from_anchor(&dev->deferred))) {
+		dev_kfree_skb(urb->context);
+		kfree(urb->sg);
+		usb_free_urb(urb);
+	}
 
 	if (dev->driver_info->unbind)
 		dev->driver_info->unbind(dev, intf);
-- 
2.20.1

Re: [PATCH net] usbnet: Fix memory leak in usbnet_disconnect()

[Oliver Neukum]

On 23.09.22 06:25, Peilin Ye wrote:
Hi,

> I think we may have similar issues at other usb_scuttle_anchored_urbs()
> call sites.  Since urb->context is (void *), should we pass a "destructor"
> callback to usb_scuttle_anchored_urbs(), or replace this function with
> usb_get_from_anchor() loops like this patch does?
> 

please introduce a new function with an additional parameter
for that, so that we do not need to touch the correct usages.

	Regards
		Oliver

Re: [PATCH net] usbnet: Fix memory leak in usbnet_disconnect()

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Thu, 22 Sep 2022 21:25:51 -0700 you wrote:
> From: Peilin Ye <peilin.ye@bytedance.com>
> 
> Currently usbnet_disconnect() unanchors and frees all deferred URBs
> using usb_scuttle_anchored_urbs(), which does not free urb->context,
> causing a memory leak as reported by syzbot.
> 
> Use a usb_get_from_anchor() while loop instead, similar to what we did
> in commit 19cfe912c37b ("Bluetooth: btusb: Fix memory leak in
> play_deferred").  Also free urb->sg.
> 
> [...]

Here is the summary with links:
  - [net] usbnet: Fix memory leak in usbnet_disconnect()
    https://git.kernel.org/netdev/net/c/a43206156263

You are awesome, thank you!
-- 
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