Re: kernel BUG at net/core/net-sysfs.c:LINE!

[Eric Dumazet]

On 04/03/2019 08:19 PM, wanghai (M) wrote:
> Can someone fix this issue? Thanks.

What do you mean by this exactly ?

It seems your patch added a regression, so you should either revert the patch
or fix this yourself.

> 
> å 2019/3/23 15:32, syzbot åé:
>> Hello,
>>
>> syzbot found the following crash on:
>>
>> HEAD commit:ÂÂÂ e382d91f Add linux-next specific files for 20190322
>> git tree:ÂÂÂÂÂÂ linux-next
>> console output: https://syzkaller.appspot.com/x/log.txt?x=1737671b200000
>> kernel config: https://syzkaller.appspot.com/x/.config?x=3d850e8b394c7a19
>> dashboard link: https://syzkaller.appspot.com/bug?extid=6024817a931b2830bc93
>> compiler:ÂÂÂÂÂÂ gcc (GCC) 9.0.0 20181231 (experimental)
>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1795613b200000
>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10f5a437200000
>>
>> The bug was bisected to:
>>
>> commit 6b70fc94afd165342876e53fc4b2f7d085009945
>> Author: Wang Hai <wanghai26@xxxxxxxxxx>
>> Date:ÂÂ Wed Mar 20 18:25:05 2019 +0000
>>
>> ÂÂÂ net-sysfs: Fix memory leak in netdev_register_kobject
>>
>> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1522556d200000
>> final crash: https://syzkaller.appspot.com/x/report.txt?x=1722556d200000
>> console output: https://syzkaller.appspot.com/x/log.txt?x=1322556d200000
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+6024817a931b2830bc93@xxxxxxxxxxxxxxxxxxxxxxxxx
>> Fixes: 6b70fc94afd1 ("net-sysfs: Fix memory leak in netdev_register_kobject")
>>
>> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441399
>> RDX: 0000000020000080 RSI: 00000000000089f1 RDI: 0000000000000006
>> RBP: 00007ffcd20666d0 R08: 0000000000000001 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
>> R13: 0000000000000007 R14: 0000000000000000 R15: 0000000000000000
>> ------------[ cut here ]------------
>> kernel BUG at net/core/net-sysfs.c:1631!
>> invalid opcode: 0000 [#1] PREEMPT SMP KASAN
>> CPU: 1 PID: 8035 Comm: syz-executor344 Not tainted 5.1.0-rc1-next-20190322 #9
>> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
>> RIP: 0010:netdev_release net/core/net-sysfs.c:1631 [inline]
>> RIP: 0010:netdev_release+0x92/0xb0 net/core/net-sysfs.c:1627
>> Code: 48 c1 ea 03 80 3c 02 00 75 29 48 8b bb 80 fa ff ff e8 12 77 20 fc 4c 89 ef e8 7a cc f5 ff 5b 41 5c 41 5d 5d c3 e8 9e 9b e8 fb <0f> 0b e8 27 b1 20 fc eb 9c e8 80 b1 20 fc eb d0 0f 1f 40 00 66 2e
>> RSP: 0018:ffff88808d6af718 EFLAGS: 00010293
>> RAX: ffff8880a87902c0 RBX: ffff88808e3612a0 RCX: ffffffff8587fc89
>> RDX: 0000000000000000 RSI: ffffffff8587fcd2 RDI: 0000000000000001
>> RBP: ffff88808d6af730 R08: ffff8880a87902c0 R09: ffff8880a8790b60
>> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
>> R13: ffff88808e360d00 R14: 0000000000000000 R15: 0000000000000000
>> FS:Â 0000000001752880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
>> CS:Â 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000000000000 CR3: 0000000098da2000 CR4: 00000000001406e0
>> Call Trace:
>> Âdevice_release+0x7d/0x210 drivers/base/core.c:1064
>> Âkobject_cleanup lib/kobject.c:662 [inline]
>> Âkobject_release lib/kobject.c:691 [inline]
>> Âkref_put include/linux/kref.h:67 [inline]
>> Âkobject_put.cold+0x28f/0x2ec lib/kobject.c:708
>> Âput_device+0x20/0x30 drivers/base/core.c:2205
>> Ânetdev_register_kobject+0x1a1/0x3c0 net/core/net-sysfs.c:1763
>> Âregister_netdevice+0x878/0xff0 net/core/dev.c:8709
>> Âip6_tnl_create2+0x1c2/0x350 net/ipv6/ip6_tunnel.c:269
>> Âip6_tnl_create net/ipv6/ip6_tunnel.c:320 [inline]
>> Âip6_tnl_locate+0x63f/0x8d0 net/ipv6/ip6_tunnel.c:368
>> Âip6_tnl_ioctl+0x490/0xab0 net/ipv6/ip6_tunnel.c:1634
>> Âdev_ifsioc+0x257/0x990 net/core/dev_ioctl.c:322
>> Âdev_ioctl+0x286/0xc90 net/core/dev_ioctl.c:513
>> Âsock_ioctl+0x48b/0x610 net/socket.c:1102
>> Âvfs_ioctl fs/ioctl.c:46 [inline]
>> Âfile_ioctl fs/ioctl.c:509 [inline]
>> Âdo_vfs_ioctl+0xd6e/0x1390 fs/ioctl.c:696
>> Âksys_ioctl+0xab/0xd0 fs/ioctl.c:713
>> Â__do_sys_ioctl fs/ioctl.c:720 [inline]
>> Â__se_sys_ioctl fs/ioctl.c:718 [inline]
>> Â__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
>> Âdo_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
>> Âentry_SYSCALL_64_after_hwframe+0x49/0xbe
>> RIP: 0033:0x441399
>> Code: e8 5c ae 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 bb 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
>> RSP: 002b:00007ffcd20666b8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
>> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441399
>> RDX: 0000000020000080 RSI: 00000000000089f1 RDI: 0000000000000006
>> RBP: 00007ffcd20666d0 R08: 0000000000000001 R09: 0000000000000000
>> R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
>> R13: 0000000000000007 R14: 0000000000000000 R15: 0000000000000000
>> Modules linked in:
>> ---[ end trace 0dbf190846958075 ]---
>> RIP: 0010:netdev_release net/core/net-sysfs.c:1631 [inline]
>> RIP: 0010:netdev_release+0x92/0xb0 net/core/net-sysfs.c:1627
>> Code: 48 c1 ea 03 80 3c 02 00 75 29 48 8b bb 80 fa ff ff e8 12 77 20 fc 4c 89 ef e8 7a cc f5 ff 5b 41 5c 41 5d 5d c3 e8 9e 9b e8 fb <0f> 0b e8 27 b1 20 fc eb 9c e8 80 b1 20 fc eb d0 0f 1f 40 00 66 2e
>> RSP: 0018:ffff88808d6af718 EFLAGS: 00010293
>> RAX: ffff8880a87902c0 RBX: ffff88808e3612a0 RCX: ffffffff8587fc89
>> RDX: 0000000000000000 RSI: ffffffff8587fcd2 RDI: 0000000000000001
>> RBP: ffff88808d6af730 R08: ffff8880a87902c0 R09: ffff8880a8790b60
>> R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
>> R13: ffff88808e360d00 R14: 0000000000000000 R15: 0000000000000000
>> FS:Â 0000000001752880(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
>> CS:Â 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> CR2: 0000000000000000 CR3: 0000000098da2000 CR4: 00000000001406e0
>>
>>
>> ---
>> 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.
>> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>> syzbot can test patches for this bug, for details see:
>> https://goo.gl/tpsmEJ#testing-patches
>>
>> .
>>
>