syzbot


WARNING: refcount bug in ip6_tnl_dev_uninit

Status: fixed on 2021/11/10 00:50
Reported-by: syzbot+@syzkaller.appspotmail.com
Fix commit: 0d7a7b2014b1 ipv6: remove extra dev_hold() for fallback tunnels
First crash: 549d, last: 544d

Cause bisection: introduced by (bisect log) :
commit 997acaf6b4b59c6a9c259740312a69ea549cc684
Author: Mark Rutland <mark.rutland@arm.com>
Date: Mon Jan 11 15:37:07 2021 +0000

  lockdep: report broken irq restoration

Crash: WARNING in kvm_wait (log)
Repro: C syz .config

Sample crash report:
netlink: 8 bytes leftover after parsing attributes in process `syz-executor057'.
------------[ cut here ]------------
refcount_t: decrement hit 0; leaking memory.
WARNING: CPU: 1 PID: 8390 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31
Modules linked in:
CPU: 0 PID: 8390 Comm: syz-executor057 Not tainted 5.12.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:refcount_warn_saturate+0xbf/0x1e0 lib/refcount.c:31
Code: 1d 6a 5a e8 09 31 ff 89 de e8 8d 1a ab fd 84 db 75 e0 e8 d4 13 ab fd 48 c7 c7 a0 e1 c1 89 c6 05 4a 5a e8 09 01 e8 2e 36 fb 04 <0f> 0b eb c4 e8 b8 13 ab fd 0f b6 1d 39 5a e8 09 31 ff 89 de e8 58
RSP: 0018:ffffc9000160efe8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: ffff88801fa33880 RSI: ffffffff815c51f5 RDI: fffff520002c1def
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff815bdf8e R11: 0000000000000000 R12: ffff888018290568
R13: ffff888147ac7800 R14: 00000000ffffffff R15: ffffffff8d659b80
FS:  0000000001244300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558abbb67188 CR3: 0000000012a88000 CR4: 00000000001506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 __refcount_dec include/linux/refcount.h:344 [inline]
 refcount_dec include/linux/refcount.h:359 [inline]
 dev_put include/linux/netdevice.h:4135 [inline]
 ip6_tnl_dev_uninit+0x370/0x3d0 net/ipv6/ip6_tunnel.c:387
 register_netdevice+0xadf/0x1500 net/core/dev.c:10308
 ip6_tnl_create2+0x1b5/0x400 net/ipv6/ip6_tunnel.c:263
 ip6_tnl_newlink+0x312/0x580 net/ipv6/ip6_tunnel.c:2052
 __rtnl_newlink+0x1062/0x1710 net/core/rtnetlink.c:3443
 rtnl_newlink+0x64/0xa0 net/core/rtnetlink.c:3491
 rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5553
 netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2502
 netlink_unicast_kernel net/netlink/af_netlink.c:1312 [inline]
 netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1338
 netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1927
 sock_sendmsg_nosec net/socket.c:654 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:674
 ____sys_sendmsg+0x6e8/0x810 net/socket.c:2350
 ___sys_sendmsg+0xf3/0x170 net/socket.c:2404
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2433
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x43fd19
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffe21e4b8a8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000011fde RCX: 000000000043fd19
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffe21e4ba48 R09: 00007ffe21e4ba48
R10: 00007ffe21e4ba48 R11: 0000000000000246 R12: 00007ffe21e4b8bc
R13: 431bde82d7b634db R14: 00000000004ae018 R15: 0000000000400488

Crashes (16):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci-upstream-net-kasan-gce 2021/03/28 17:02 net-next a1281601f88e a8529b82 .config log report syz C WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/29 01:40 net-next a1281601f88e a8529b82 .config log report syz WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/28 12:40 net-next a1281601f88e a8529b82 .config log report syz WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/31 22:31 net-next 37f368d8d09d 6a81331a .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/31 10:36 net-next 37f368d8d09d 6a81331a .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/31 09:10 net-next 37f368d8d09d 6a81331a .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/30 13:03 net-next 37f368d8d09d 6a81331a .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/30 00:06 net-next 37f368d8d09d 6a81331a .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/29 21:59 net-next 37f368d8d09d 6a81331a .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/29 03:23 net-next a1281601f88e a8529b82 .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/28 16:31 net-next a1281601f88e a8529b82 .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/28 12:22 net-next a1281601f88e a8529b82 .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/27 07:34 net-next a1281601f88e a8529b82 .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-net-kasan-gce 2021/03/27 07:15 net-next a1281601f88e a8529b82 .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-linux-next-kasan-gce-root 2021/04/01 10:04 linux-next 931294922e65 6a81331a .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
ci-upstream-linux-next-kasan-gce-root 2021/03/30 10:33 linux-next 931294922e65 6a81331a .config log report info WARNING: refcount bug in ip6_tnl_dev_uninit
* Struck through repros no longer work on HEAD.