Subject: Re: WARNING: locking bug in inet_autobind

From: syzbot <[email-masked]>
Date: Tue, 21 May 2019 01:31:05 -0700

syzbot has found a reproducer for the following crash on:

HEAD commit:    f49aa1de Merge tag 'for-5.2-rc1-tag' of git://git.kernel.o..
git tree:       net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=14e5b130a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fc045131472947d7
dashboard link: https://syzkaller.appspot.com/bug?extid=94cc2a66fc228b23f360
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=163731f8a00000

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

WARNING: CPU: 1 PID: 28592 at kernel/locking/lockdep.c:734  
arch_local_save_flags arch/x86/include/asm/paravirt.h:762 [inline]
WARNING: CPU: 1 PID: 28592 at kernel/locking/lockdep.c:734  
arch_local_save_flags arch/x86/include/asm/paravirt.h:760 [inline]
WARNING: CPU: 1 PID: 28592 at kernel/locking/lockdep.c:734  
look_up_lock_class kernel/locking/lockdep.c:725 [inline]
WARNING: CPU: 1 PID: 28592 at kernel/locking/lockdep.c:734  
register_lock_class+0xe10/0x1860 kernel/locking/lockdep.c:1078
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 28592 Comm: syz-executor.5 Not tainted 5.2.0-rc1+ #1
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+0x172/0x1f0 lib/dump_stack.c:113
  panic+0x2cb/0x744 kernel/panic.c:218
  __warn.cold+0x20/0x4d kernel/panic.c:575
  report_bug+0x263/0x2b0 lib/bug.c:186
  fixup_bug arch/x86/kernel/traps.c:179 [inline]
  fixup_bug arch/x86/kernel/traps.c:174 [inline]
  do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
  do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:986
RIP: 0010:look_up_lock_class kernel/locking/lockdep.c:734 [inline]
RIP: 0010:register_lock_class+0xe10/0x1860 kernel/locking/lockdep.c:1078
Code: 00 48 89 da 4d 8b 76 c0 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80  
3c 02 00 0f 85 23 07 00 00 4c 89 33 e9 e3 f4 ff ff 0f 0b <0f> 0b e9 ea f3  
ff ff 44 89 e0 4c 8b 95 50 ff ff ff 83 c0 01 4c 8b
RSP: 0018:ffff888093d179e8 EFLAGS: 00010083
RAX: dffffc0000000000 RBX: ffff8880967cd160 RCX: 0000000000000000
RDX: 1ffff11012cf9a2f RSI: 0000000000000000 RDI: ffff8880967cd178
RBP: ffff888093d17ab0 R08: 1ffff110127a2f45 R09: ffffffff8a659d40
R10: ffffffff8a2e8440 R11: 0000000000000000 R12: ffffffff8a323030
R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff88022ba0
  __lock_acquire+0x116/0x5490 kernel/locking/lockdep.c:3673
  lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4302
  __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
  _raw_spin_lock_bh+0x33/0x50 kernel/locking/spinlock.c:175
  spin_lock_bh include/linux/spinlock.h:343 [inline]
  lock_sock_nested+0x41/0x120 net/core/sock.c:2917
  lock_sock include/net/sock.h:1525 [inline]
  inet_autobind+0x20/0x1a0 net/ipv4/af_inet.c:183
  inet_dgram_connect+0x243/0x2d0 net/ipv4/af_inet.c:573
  __sys_connect+0x264/0x330 net/socket.c:1840
  __do_sys_connect net/socket.c:1851 [inline]
  __se_sys_connect net/socket.c:1848 [inline]
  __x64_sys_connect+0x73/0xb0 net/socket.c:1848
  do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x459279
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2321b1ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459279
RDX: 000000000000001c RSI: 0000000020000000 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2321b1b6d4
R13: 00000000004bf74d R14: 00000000004d0c18 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..