Subject: WARNING in xfrm_policy_inexact_gc_tree

From: syzbot <[email-masked]>
Date: Sun, 09 Dec 2018 23:49:02 -0800

Hello,

syzbot found the following crash on:

HEAD commit:    74c4a24df7ca Add linux-next specific files for 20181207
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17bbea7d400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6e9413388bf37bed
dashboard link: https://syzkaller.appspot.com/bug?extid=0b2f1bc876d301440d44
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]

IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready
IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
8021q: adding VLAN 0 to HW filter on device team0
WARNING: CPU: 0 PID: 13116 at net/xfrm/xfrm_policy.c:1066  
xfrm_policy_inexact_gc_tree+0x233/0x280 net/xfrm/xfrm_policy.c:1066
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 13116 Comm: kworker/u4:10 Not tainted 4.20.0-rc5-next-20181207+  
#163
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x244/0x39d lib/dump_stack.c:113
  panic+0x2ad/0x632 kernel/panic.c:214
  __warn.cold.8+0x20/0x4f kernel/panic.c:571
  report_bug+0x254/0x2d0 lib/bug.c:186
  fixup_bug arch/x86/kernel/traps.c:178 [inline]
  do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
  do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969
RIP: 0010:xfrm_policy_inexact_gc_tree+0x233/0x280  
net/xfrm/xfrm_policy.c:1066
Code: 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 d6 00 ae fa 0f b6 9d 2b ff ff  
ff 31 ff 89 de e8 96 01 ae fa 84 db 74 8c e8 bd 00 ae fa <0f> 0b eb 83 48  
8d 7d 98 e8 e0 00 f2 fa e9 d0 fe ff ff e8 36 00 f2
RSP: 0018:ffff88819c307108 EFLAGS: 00010293
RAX: ffff8881be8a82c0 RBX: 0000000000000001 RCX: ffffffff86d1f6ea
RDX: 0000000000000000 RSI: ffffffff86d1f6f3 RDI: 0000000000000001
RBP: ffff88819c3071f0 R08: ffff8881be8a82c0 R09: 0000000000000008
R10: 0000000000000e65 R11: ffff8881be8a82c0 R12: dffffc0000000000
R13: ffffed1033860e31 R14: ffff8881be45a330 R15: ffff8881bf82cdc8
  __xfrm_policy_inexact_prune_bin+0x123/0x420 net/xfrm/xfrm_policy.c:1079
  xfrm_policy_fini+0x473/0x650 net/xfrm/xfrm_policy.c:3887
  xfrm_net_exit+0x1d/0x70 net/xfrm/xfrm_policy.c:3928
  ops_exit_list.isra.5+0xb0/0x160 net/core/net_namespace.c:153
  cleanup_net+0x555/0xb10 net/core/net_namespace.c:551
  process_one_work+0xc90/0x1c40 kernel/workqueue.c:2153
kobject: 'loop5' (00000000d2e25176): kobject_uevent_env
kobject: 'loop5' (00000000d2e25176): fill_kobj_path: path  
= '/devices/virtual/block/loop5'
  worker_thread+0x17f/0x1390 kernel/workqueue.c:2296
  kthread+0x35a/0x440 kernel/kthread.c:246
  ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352
Kernel Offset: disabled
Rebooting in 86400 seconds..

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