memory leak in tipc_buf_acquire

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 4dde821e Merge tag 'xfs-5.2-fixes-1' of git://git.kernel.o..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=107db73aa00000
kernel config: https://syzkaller.appspot.com/x/.config?x=61dd9e15a761691d
dashboard link: https://syzkaller.appspot.com/bug?extid=78fbe679c8ca8d264a8d
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162bd84ca00000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=160c605ca00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+78fbe6...@syzkaller.appspotmail.com

type=1400 audit(1558701681.775:36): avc: denied { map } for pid=7128
comm="syz-executor987" path="/root/syz-executor987656147" dev="sda1"
ino=15900 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023
tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
executing program
executing program
executing program
executing program
BUG: memory leak
unreferenced object 0xffff88810df83c00 (size 512):
comm "softirq", pid 0, jiffies 4294942354 (age 19.830s)
hex dump (first 32 bytes):
38 1a 0d 0f 81 88 ff ff 38 1a 0d 0f 81 88 ff ff 8.......8.......
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<000000009375ee42>] kmemleak_alloc_recursive
include/linux/kmemleak.h:55 [inline]
[<000000009375ee42>] slab_post_alloc_hook mm/slab.h:439 [inline]
[<000000009375ee42>] slab_alloc_node mm/slab.c:3269 [inline]
[<000000009375ee42>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
[<000000004c563922>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
[<00000000ec87bfa1>] alloc_skb_fclone include/linux/skbuff.h:1107
[inline]
[<00000000ec87bfa1>] tipc_buf_acquire+0x2f/0x80 net/tipc/msg.c:66
[<00000000d151ef84>] tipc_msg_create+0x37/0xe0 net/tipc/msg.c:98
[<000000008bb437b0>] tipc_group_create_event+0xb3/0x1b0
net/tipc/group.c:679
[<00000000947b1d0f>] tipc_group_proto_rcv+0x569/0x640
net/tipc/group.c:781
[<00000000b75ab039>] tipc_sk_proto_rcv net/tipc/socket.c:1996 [inline]
[<00000000b75ab039>] tipc_sk_filter_rcv+0x9ac/0xf20
net/tipc/socket.c:2163
[<000000000dab7a6c>] tipc_sk_enqueue net/tipc/socket.c:2255 [inline]
[<000000000dab7a6c>] tipc_sk_rcv+0x494/0x8a0 net/tipc/socket.c:2306
[<00000000023a7ddd>] tipc_node_xmit+0x196/0x1f0 net/tipc/node.c:1442
[<00000000337dd9eb>] tipc_node_xmit_skb net/tipc/node.c:1491 [inline]
[<00000000337dd9eb>] tipc_node_distr_xmit+0x7d/0x120
net/tipc/node.c:1506
[<00000000b6375182>] tipc_group_delete+0xe6/0x130 net/tipc/group.c:224
[<000000000361ba2b>] tipc_sk_leave+0x57/0xb0 net/tipc/socket.c:2925
[<000000009df90505>] tipc_release+0x7b/0x5e0 net/tipc/socket.c:584
[<000000009f3189da>] __sock_release+0x4b/0xe0 net/socket.c:607
[<00000000d3568ee0>] sock_close+0x1b/0x30 net/socket.c:1279
[<00000000266a6215>] __fput+0xed/0x300 fs/file_table.c:280

BUG: memory leak
unreferenced object 0xffff888111895400 (size 1024):
comm "softirq", pid 0, jiffies 4294942354 (age 19.830s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000e2e2855e>] kmemleak_alloc_recursive
include/linux/kmemleak.h:55 [inline]
[<00000000e2e2855e>] slab_post_alloc_hook mm/slab.h:439 [inline]
[<00000000e2e2855e>] slab_alloc_node mm/slab.c:3269 [inline]
[<00000000e2e2855e>] kmem_cache_alloc_node_trace+0x15b/0x2a0
mm/slab.c:3597
[<00000000a5030ce7>] __do_kmalloc_node mm/slab.c:3619 [inline]
[<00000000a5030ce7>] __kmalloc_node_track_caller+0x38/0x50
mm/slab.c:3634
[<0000000039212451>] __kmalloc_reserve.isra.0+0x40/0xb0
net/core/skbuff.c:142
[<00000000307cb4cf>] __alloc_skb+0xa0/0x210 net/core/skbuff.c:210
[<00000000ec87bfa1>] alloc_skb_fclone include/linux/skbuff.h:1107
[inline]
[<00000000ec87bfa1>] tipc_buf_acquire+0x2f/0x80 net/tipc/msg.c:66
[<00000000d151ef84>] tipc_msg_create+0x37/0xe0 net/tipc/msg.c:98
[<000000008bb437b0>] tipc_group_create_event+0xb3/0x1b0
net/tipc/group.c:679
[<00000000947b1d0f>] tipc_group_proto_rcv+0x569/0x640
net/tipc/group.c:781
[<00000000b75ab039>] tipc_sk_proto_rcv net/tipc/socket.c:1996 [inline]
[<00000000b75ab039>] tipc_sk_filter_rcv+0x9ac/0xf20
net/tipc/socket.c:2163
[<000000000dab7a6c>] tipc_sk_enqueue net/tipc/socket.c:2255 [inline]
[<000000000dab7a6c>] tipc_sk_rcv+0x494/0x8a0 net/tipc/socket.c:2306
[<00000000023a7ddd>] tipc_node_xmit+0x196/0x1f0 net/tipc/node.c:1442
[<00000000337dd9eb>] tipc_node_xmit_skb net/tipc/node.c:1491 [inline]
[<00000000337dd9eb>] tipc_node_distr_xmit+0x7d/0x120
net/tipc/node.c:1506
[<00000000b6375182>] tipc_group_delete+0xe6/0x130 net/tipc/group.c:224
[<000000000361ba2b>] tipc_sk_leave+0x57/0xb0 net/tipc/socket.c:2925
[<000000009df90505>] tipc_release+0x7b/0x5e0 net/tipc/socket.c:584
[<000000009f3189da>] __sock_release+0x4b/0xe0 net/socket.c:607

BUG: memory leak
unreferenced object 0xffff88810e63de00 (size 512):
comm "softirq", pid 0, jiffies 4294943548 (age 7.890s)
hex dump (first 32 bytes):
38 10 0d 0f 81 88 ff ff 38 10 0d 0f 81 88 ff ff 8.......8.......
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<000000009375ee42>] kmemleak_alloc_recursive
include/linux/kmemleak.h:55 [inline]
[<000000009375ee42>] slab_post_alloc_hook mm/slab.h:439 [inline]
[<000000009375ee42>] slab_alloc_node mm/slab.c:3269 [inline]
[<000000009375ee42>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
[<000000004c563922>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
[<00000000ec87bfa1>] alloc_skb_fclone include/linux/skbuff.h:1107
[inline]
[<00000000ec87bfa1>] tipc_buf_acquire+0x2f/0x80 net/tipc/msg.c:66
[<00000000d151ef84>] tipc_msg_create+0x37/0xe0 net/tipc/msg.c:98
[<000000008bb437b0>] tipc_group_create_event+0xb3/0x1b0
net/tipc/group.c:679
[<00000000947b1d0f>] tipc_group_proto_rcv+0x569/0x640
net/tipc/group.c:781
[<00000000b75ab039>] tipc_sk_proto_rcv net/tipc/socket.c:1996 [inline]
[<00000000b75ab039>] tipc_sk_filter_rcv+0x9ac/0xf20
net/tipc/socket.c:2163
[<000000000dab7a6c>] tipc_sk_enqueue net/tipc/socket.c:2255 [inline]
[<000000000dab7a6c>] tipc_sk_rcv+0x494/0x8a0 net/tipc/socket.c:2306
[<00000000023a7ddd>] tipc_node_xmit+0x196/0x1f0 net/tipc/node.c:1442
[<00000000337dd9eb>] tipc_node_xmit_skb net/tipc/node.c:1491 [inline]
[<00000000337dd9eb>] tipc_node_distr_xmit+0x7d/0x120
net/tipc/node.c:1506
[<00000000b6375182>] tipc_group_delete+0xe6/0x130 net/tipc/group.c:224
[<000000000361ba2b>] tipc_sk_leave+0x57/0xb0 net/tipc/socket.c:2925
[<000000009df90505>] tipc_release+0x7b/0x5e0 net/tipc/socket.c:584
[<000000009f3189da>] __sock_release+0x4b/0xe0 net/socket.c:607
[<00000000d3568ee0>] sock_close+0x1b/0x30 net/socket.c:1279
[<00000000266a6215>] __fput+0xed/0x300 fs/file_table.c:280



---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Xin Long]

On Sat, May 25, 2019 at 5:18 AM syzbot
<syzbot+78fbe6...@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 4dde821e Merge tag 'xfs-5.2-fixes-1' of git://git.kernel.o..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=107db73aa00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=61dd9e15a761691d
> dashboard link: https://syzkaller.appspot.com/bug?extid=78fbe679c8ca8d264a8d
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162bd84ca00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=160c605ca00000
>

Looks we need to purge each member's deferredq list in tipc_group_delete():
diff --git a/net/tipc/group.c b/net/tipc/group.c
index 992be61..23823eb 100644
--- a/net/tipc/group.c
+++ b/net/tipc/group.c
@@ -218,6 +218,7 @@ void tipc_group_delete(struct net *net, struct
tipc_group *grp)

rbtree_postorder_for_each_entry_safe(m, tmp, tree, tree_node) {
tipc_group_proto_xmit(grp, m, GRP_LEAVE_MSG, &xmitq);
+ __skb_queue_purge(&m->deferredq);
list_del(&m->list);
kfree(m);

[Hillf Danton]

Hi

On Fri, 24 May 2019 14:18:05 -0700 (PDT) syzbot wrote:
> Hello,
>
> syzbot found the following crash on:
>
> HEAD commit: 4dde821e Merge tag 'xfs-5.2-fixes-1' of git://git.kernel.o..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=107db73aa00000
> kernel config: https://syzkaller.appspot.com/x/.config?x=61dd9e15a761691d
> dashboard link: https://syzkaller.appspot.com/bug?extid=78fbe679c8ca8d264a8d
> compiler: gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=162bd84ca00000
> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=160c605ca00000
>

Ignore my noise if you have no interest seeing the syzbot report.

The following tiny diff, made in the hope that it may help you perhaps
handle the report, adds skb purges in the unlikely nobufs case.

Thanks
Hillf
---
net/tipc/node.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/net/tipc/node.c b/net/tipc/node.c
index 9e106d3..d9d441e 100644
--- a/net/tipc/node.c
+++ b/net/tipc/node.c
@@ -1465,11 +1465,13 @@ int tipc_node_xmit(struct net *net, struct sk_buff_head *list,
spin_unlock_bh(&le->lock);
tipc_node_read_unlock(n);

- if (unlikely(rc == -ENOBUFS))
+ if (unlikely(rc == -ENOBUFS)) {
tipc_node_link_down(n, bearer_id, false);
- else
+ skb_queue_purge(list);
+ skb_queue_purge(&xmitq);
+ } else {
tipc_bearer_xmit(net, bearer_id, &xmitq, &le->maddr);
-
+ }
tipc_node_put(n);

return rc;
--

[Jon Maloy]

> -----Original Message-----
> From: netdev...@vger.kernel.org <netdev...@vger.kernel.org> On
> Behalf Of Xin Long
> Sent: 9-Jun-19 14:45
> To: syzbot <syzbot+78fbe6...@syzkaller.appspotmail.com>
> Cc: davem <da...@davemloft.net>; Jon Maloy <jon....@ericsson.com>;
> LKML <linux-...@vger.kernel.org>; network dev
> <net...@vger.kernel.org>; syzkaller-bugs <syzkaller-
> bu...@googlegroups.com>; tipc-di...@lists.sourceforge.net; Ying Xue
> <ying...@windriver.com>
> Subject: Re: memory leak in tipc_buf_acquire

>
> On Sat, May 25, 2019 at 5:18 AM syzbot
> <syzbot+78fbe6...@syzkaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following crash on:
> >
> > HEAD commit: 4dde821e Merge tag 'xfs-5.2-fixes-1' of git://git.kernel.o..
> > git tree: upstream
> > console output:

> > https://protect2.fireeye.com/url?k=2a9bdca3-761109b5-2a9b9c38-
> 862f14a9
> > 365e-
> 4ed8fb52eb782aab&q=1&u=https%3A%2F%2Fsyzkaller.appspot.com%2Fx%
> 2F
> > log.txt%3Fx%3D107db73aa00000 kernel config:
> > https://protect2.fireeye.com/url?k=a1863015-fd0ce503-a186708e-
> 862f14a9
> > 365e-
> 04056f2111354660&q=1&u=https%3A%2F%2Fsyzkaller.appspot.com%2Fx%
> 2F
> > .config%3Fx%3D61dd9e15a761691d dashboard link:
> > https://protect2.fireeye.com/url?k=ba923b23-e618ee35-ba927bb8-
> 862f14a9365e-
> 6187e2f343fe3a3e&q=1&u=https%3A%2F%2Fsyzkaller.appspot.com%2Fbug
> %3Fextid%3D78fbe679c8ca8d264a8d

> > compiler: gcc (GCC) 9.0.0 20181231 (experimental)

> > syz repro: https://protect2.fireeye.com/url?k=27ea1a58-7b60cf4e-
> 27ea5ac3-862f14a9365e-
> f17f13fb7f100fa1&q=1&u=https%3A%2F%2Fsyzkaller.appspot.com%2Fx%2
> Frepro.syz%3Fx%3D162bd84ca00000
> > C reproducer: https://protect2.fireeye.com/url?k=dbe4799b-876eac8d-
> dbe43900-862f14a9365e-
> 787a755a5a1800d6&q=1&u=https%3A%2F%2Fsyzkaller.appspot.com%2Fx
> %2Frepro.c%3Fx%3D160c605ca00000

> >
> Looks we need to purge each member's deferredq list in tipc_group_delete():
> diff --git a/net/tipc/group.c b/net/tipc/group.c index 992be61..23823eb
> 100644
> --- a/net/tipc/group.c
> +++ b/net/tipc/group.c
> @@ -218,6 +218,7 @@ void tipc_group_delete(struct net *net, struct
> tipc_group *grp)
>
> rbtree_postorder_for_each_entry_safe(m, tmp, tree, tree_node) {
> tipc_group_proto_xmit(grp, m, GRP_LEAVE_MSG, &xmitq);
> + __skb_queue_purge(&m->deferredq);
> list_del(&m->list);
> kfree(m);
> }

Yes, I think you are right. I'll check it further.

Thanks
///jon

> > See https://protect2.fireeye.com/url?k=6424a141-38ae7457-6424e1da-
> 862f14a9365e-
> 29d28d4e37c9de97&q=1&u=https%3A%2F%2Fgoo.gl%2FtpsmEJ for more

> information about syzbot.
> > syzbot engineers can be reached at syzk...@googlegroups.com.
> >
> > syzbot will keep track of this bug report. See:

> > https://protect2.fireeye.com/url?k=e3266fe7-bfacbaf1-e3262f7c-
> 862f14a9365e-
> 80a14dc097f61dfe&q=1&u=https%3A%2F%2Fgoo.gl%2FtpsmEJ%23status

> for how to communicate with syzbot.
> > syzbot can test patches for this bug, for details see:

> > https://protect2.fireeye.com/url?k=26e2f1e8-7a6824fe-26e2b173-
> 862f14a9
> > 365e-
> e569ee98f89625d4&q=1&u=https%3A%2F%2Fgoo.gl%2FtpsmEJ%23testing-
> pa
> > tches

[Ying Xue]

On 6/10/19 2:44 AM, Xin Long wrote:
> Looks we need to purge each member's deferredq list in tipc_group_delete():
> diff --git a/net/tipc/group.c b/net/tipc/group.c
> index 992be61..23823eb 100644
> --- a/net/tipc/group.c
> +++ b/net/tipc/group.c
> @@ -218,6 +218,7 @@ void tipc_group_delete(struct net *net, struct
> tipc_group *grp)
>
> rbtree_postorder_for_each_entry_safe(m, tmp, tree, tree_node) {
> tipc_group_proto_xmit(grp, m, GRP_LEAVE_MSG, &xmitq);
> + __skb_queue_purge(&m->deferredq);
> list_del(&m->list);
> kfree(m);
> }

Good catch! I agree with you.