Subject: WARNING: ODEBUG bug in del_timer

From: syzbot <[email-masked]>
Date: Sun, 29 Apr 2018 09:10:02 -0700

Hello,

syzbot hit the following crash on net-next commit
af201bab50a89aa6cf4df952b2c3bf55895c8eee (Fri Apr 27 15:12:10 2018 +0000)
udp: remove stray export symbol
syzbot dashboard link:  
https://syzkaller.appspot.com/bug?extid=03faa2dc16b8b64be396

So far this crash happened 26 times on net-next.
C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5925539139289088
syzkaller reproducer:  
https://syzkaller.appspot.com/x/repro.syz?id=4983245594689536
Raw console output:  
https://syzkaller.appspot.com/x/log.txt?id=5476181675606016
Kernel config:  
https://syzkaller.appspot.com/x/.config?id=4410550353033654931
compiler: gcc (GCC) 8.0.1 20180413 (experimental)

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: [email-masked]
It will help syzbot understand when the bug is fixed. See footer for  
details.
If you forward the report, please keep this part and the footer.

random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
------------[ cut here ]------------
ODEBUG: assert_init not available (active state 0) object type: timer_list  
hint:           (null)
WARNING: CPU: 1 PID: 4490 at lib/debugobjects.c:329  
debug_print_object+0x16a/0x210 lib/debugobjects.c:326
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4490 Comm: syz-executor609 Not tainted 4.17.0-rc2+ #23
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x1b9/0x294 lib/dump_stack.c:113
  panic+0x22f/0x4de kernel/panic.c:184
  __warn.cold.8+0x163/0x1b3 kernel/panic.c:536
  report_bug+0x252/0x2d0 lib/bug.c:186
  fixup_bug arch/x86/kernel/traps.c:178 [inline]
  do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296
  do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
RIP: 0010:debug_print_object+0x16a/0x210 lib/debugobjects.c:326
RSP: 0018:ffff8801af1e7880 EFLAGS: 00010086
RAX: 0000000000000061 RBX: 0000000000000005 RCX: ffffffff818433e8
RDX: 0000000000000000 RSI: ffffffff8160f561 RDI: 0000000000000001
RBP: ffff8801af1e78c0 R08: ffff8801afa62100 R09: ffffed003b5e3eb2
R10: ffffed003b5e3eb2 R11: ffff8801daf1f597 R12: 0000000000000001
R13: ffffffff88d96cc0 R14: ffffffff87fa34e0 R15: ffffffff81666d30
  debug_object_assert_init+0x309/0x500 lib/debugobjects.c:692
  debug_timer_assert_init kernel/time/timer.c:724 [inline]
  debug_assert_init kernel/time/timer.c:776 [inline]
  del_timer+0x74/0x140 kernel/time/timer.c:1198
  try_to_grab_pending+0x439/0x9a0 kernel/workqueue.c:1223
  mod_delayed_work_on+0x91/0x250 kernel/workqueue.c:1592
  mod_delayed_work include/linux/workqueue.h:541 [inline]
  smc_setsockopt+0x33d/0x630 net/smc/af_smc.c:1353
  __sys_setsockopt+0x1bd/0x390 net/socket.c:1903
  __do_sys_setsockopt net/socket.c:1914 [inline]
  __se_sys_setsockopt net/socket.c:1911 [inline]
  __x64_sys_setsockopt+0xbe/0x150 net/socket.c:1911
  do_syscall_64+0x1b1/0x800 arch/x86/entry/common.c:287
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x43fd09
RSP: 002b:00007ffe1f251c58 EFLAGS: 00000207 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 000000000043fd09
RDX: 0000000000000001 RSI: 0000000000000006 RDI: 0000000000000003
RBP: 00000000006ca018 R08: 0000000000000004 R09: 00000000004002c8
R10: 0000000020000180 R11: 0000000000000207 R12: 0000000000401630
R13: 00000000004016c0 R14: 0000000000000000 R15: 0000000000000000
Dumping ftrace buffer:
    (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..

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