Re: WARNING: locking bug in do_ipv6_getsockopt

[Eric Dumazet]

On 7/2/19 9:17 AM, syzbot wrote:
> Hello,
> 
> syzbot found the following crash on:
> 
> HEAD commit:ÂÂÂ 6fbc7275 Linux 5.2-rc7
> git tree:ÂÂÂÂÂÂ upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=13fb8fe5a00000
> kernel config:Â https://syzkaller.appspot.com/x/.config?x=f6451f0da3d42d53
> dashboard link: https://syzkaller.appspot.com/bug?extid=babfdd7368c72aac3875
> compiler:ÂÂÂÂÂÂ gcc (GCC) 9.0.0 20181231 (experimental)
> syz repro:ÂÂÂÂÂ https://syzkaller.appspot.com/x/repro.syz?x=1460390ba00000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+babfdd7368c72aac3875@xxxxxxxxxxxxxxxxxxxxxxxxx
> 
> WARNING: CPU: 1 PID: 18374 at kernel/locking/lockdep.c:735 arch_local_save_flags arch/x86/include/asm/paravirt.h:762 [inline]
> WARNING: CPU: 1 PID: 18374 at kernel/locking/lockdep.c:735 arch_local_save_flags arch/x86/include/asm/paravirt.h:760 [inline]
> WARNING: CPU: 1 PID: 18374 at kernel/locking/lockdep.c:735 look_up_lock_class kernel/locking/lockdep.c:726 [inline]
> WARNING: CPU: 1 PID: 18374 at kernel/locking/lockdep.c:735 register_lock_class+0xe10/0x1860 kernel/locking/lockdep.c:1079

WARN_ON_ONCE(class->name != lock->name);

Might be useful to trace the content of class->name and lock->name.


> Kernel panic - not syncing: panic_on_warn set ...
> CPU: 1 PID: 18374 Comm: syz-executor.0 Not tainted 5.2.0-rc7 #65
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> Call Trace:
> Â__dump_stack lib/dump_stack.c:77 [inline]
> Âdump_stack+0x172/0x1f0 lib/dump_stack.c:113
> Âpanic+0x2cb/0x744 kernel/panic.c:219
> Â__warn.cold+0x20/0x4d kernel/panic.c:576
> Âreport_bug+0x263/0x2b0 lib/bug.c:186
> Âfixup_bug arch/x86/kernel/traps.c:179 [inline]
> Âfixup_bug arch/x86/kernel/traps.c:174 [inline]
> Âdo_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:272
> Âdo_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:291
> Âinvalid_op+0x14/0x20 arch/x86/entry/entry_64.S:986
> RIP: 0010:look_up_lock_class kernel/locking/lockdep.c:735 [inline]
> RIP: 0010:register_lock_class+0xe10/0x1860 kernel/locking/lockdep.c:1079
> 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:ffff88809ea3f678 EFLAGS: 00010087
> RAX: dffffc0000000000 RBX: ffff888090b948e0 RCX: 0000000000000000
> RDX: 1ffff1101217291f RSI: 0000000000000000 RDI: ffff888090b948f8
> RBP: ffff88809ea3f740 R08: 1ffff11013d47ed7 R09: ffffffff8a65ad40
> R10: ffffffff8a2e9180 R11: 0000000000000000 R12: ffffffff8a3243a0
> R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff88023e60
> Â__lock_acquire+0x116/0x5490 kernel/locking/lockdep.c:3674
> Âlock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4303
> Â__raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
> Â_raw_spin_lock_bh+0x33/0x50 kernel/locking/spinlock.c:175
> Âspin_lock_bh include/linux/spinlock.h:343 [inline]
> Âlock_sock_nested+0x41/0x120 net/core/sock.c:2913
> Âlock_sock include/net/sock.h:1522 [inline]
> Âdo_ipv6_getsockopt.isra.0+0x289/0x2590 net/ipv6/ipv6_sockglue.c:1167
> Âipv6_getsockopt+0x186/0x280 net/ipv6/ipv6_sockglue.c:1391
> Âudpv6_getsockopt+0x68/0xa0 net/ipv6/udp.c:1590
> Âsock_common_getsockopt+0x94/0xd0 net/core/sock.c:3085
> Â__sys_getsockopt+0x15f/0x240 net/socket.c:2109
> Â__do_sys_getsockopt net/socket.c:2120 [inline]
> Â__se_sys_getsockopt net/socket.c:2117 [inline]
> Â__x64_sys_getsockopt+0xbe/0x150 net/socket.c:2117
> Âdo_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
> Âentry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x4597c9
> 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:00007fb5fd78ac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
> RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00000000004597c9
> RDX: 0000000000000036 RSI: 0000000000000029 RDI: 0000000000000004
> RBP: 000000000075bfc8 R08: 0000000020000080 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 00007fb5fd78b6d4
> R13: 00000000004c0803 R14: 00000000004d2b88 R15: 00000000ffffffff
> Kernel Offset: disabled
> Rebooting in 86400 seconds..
> 
> 
> ---
> 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 syzkaller@xxxxxxxxxxxxxxxxx
> 
> 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