Subject: [syzbot] WARNING in netlink_sock_destruct

From: syzbot <[email-masked]>
Date: Wed, 04 Aug 2021 17:31:17 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    f3438b4c4e69 Merge tag '5.14-rc3-smb3-fixes' of git://git...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=127416d4300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=bfd78f4abd4edaa6
dashboard link: https://syzkaller.appspot.com/bug?extid=987e85fbd9c71706c130
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
userspace arch: i386

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

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

------------[ cut here ]------------
WARNING: CPU: 0 PID: 1042 at net/netlink/af_netlink.c:410 netlink_sock_destruct+0x230/0x2b0 net/netlink/af_netlink.c:410
Modules linked in:
CPU: 0 PID: 1042 Comm: syz-executor.0 Not tainted 5.14.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:netlink_sock_destruct+0x230/0x2b0 net/netlink/af_netlink.c:410
Code: df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 8a 00 00 00 48 83 bd d8 04 00 00 00 75 15 5b 5d 41 5c e9 a5 3a 22 fa e8 a0 3a 22 fa <0f> 0b e9 68 ff ff ff e8 94 3a 22 fa 0f 0b 5b 5d 41 5c e9 89 3a 22
RSP: 0018:ffffc90000007d90 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 0000000000000407 RCX: 0000000000000100
RDX: ffff88808faa8000 RSI: ffffffff875360c0 RDI: 0000000000000003
RBP: ffff888000170000 R08: 0000000000000000 R09: ffff88800017020b
R10: ffffffff87536027 R11: 0000000000000000 R12: ffff888000170208
R13: ffff888000170030 R14: 0000000000000002 R15: ffff888000170688
FS:  0000000000000000(0000) GS:ffff8880b9c00000(0063) knlGS:00000000f552db40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000002e826000 CR3: 00000000938ef000 CR4: 00000000001526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>
 __sk_destruct+0x4b/0x900 net/core/sock.c:1900
 sk_destruct+0xbd/0xe0 net/core/sock.c:1944
 __sk_free+0xef/0x3d0 net/core/sock.c:1955
 sk_free+0x78/0xa0 net/core/sock.c:1966
 deferred_put_nlk_sk+0x151/0x2f0 net/netlink/af_netlink.c:740
 rcu_do_batch kernel/rcu/tree.c:2550 [inline]
 rcu_core+0x7ab/0x1380 kernel/rcu/tree.c:2785
 __do_softirq+0x29b/0x9c2 kernel/softirq.c:558
 do_softirq.part.0+0xde/0x130 kernel/softirq.c:459
 </IRQ>
 do_softirq kernel/softirq.c:451 [inline]
 __local_bh_enable_ip+0x102/0x120 kernel/softirq.c:383
 local_bh_enable include/linux/bottom_half.h:32 [inline]
 rcu_read_unlock_bh include/linux/rcupdate.h:757 [inline]
 __dev_queue_xmit+0x1b04/0x3620 net/core/dev.c:4312
 __netlink_deliver_tap_skb net/netlink/af_netlink.c:303 [inline]
 __netlink_deliver_tap net/netlink/af_netlink.c:321 [inline]
 netlink_deliver_tap+0x9b5/0xbc0 net/netlink/af_netlink.c:334
 netlink_deliver_tap_kernel net/netlink/af_netlink.c:343 [inline]
 netlink_unicast_kernel net/netlink/af_netlink.c:1313 [inline]
 netlink_unicast+0x5e5/0x7d0 net/netlink/af_netlink.c:1340
 netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
 sock_sendmsg_nosec net/socket.c:703 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:723
 sock_no_sendpage+0xf3/0x130 net/core/sock.c:2959
 kernel_sendpage.part.0+0x1a0/0x340 net/socket.c:3673
 kernel_sendpage net/socket.c:3670 [inline]
 sock_sendpage+0xe5/0x140 net/socket.c:1002
 pipe_to_sendpage+0x2ad/0x380 fs/splice.c:364
 splice_from_pipe_feed fs/splice.c:418 [inline]
 __splice_from_pipe+0x43e/0x8a0 fs/splice.c:562
 splice_from_pipe fs/splice.c:597 [inline]
 generic_splice_sendpage+0xd4/0x140 fs/splice.c:746
 do_splice_from fs/splice.c:767 [inline]
 do_splice+0xb7e/0x1960 fs/splice.c:1079
 __do_splice+0x134/0x250 fs/splice.c:1144
 __do_sys_splice fs/splice.c:1350 [inline]
 __se_sys_splice fs/splice.c:1332 [inline]
 __ia32_sys_splice+0x195/0x250 fs/splice.c:1332
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x2f/0x70 arch/x86/entry/common.c:203
 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7f54549
Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f552d5fc EFLAGS: 00000296 ORIG_RAX: 0000000000000139
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000000000
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 000000000004ffe0
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

---
This report 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 [email-masked].

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.