Forwarded: Re: [syzbot] [net?] general protection fault in bond_header_create

[syzbot <syzbot+3d8bc31c45e11450f24c@syzkaller.appspotmail.com>]

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***

Subject: Re: [syzbot] [net?] general protection fault in bond_header_create
Author: jiayuan.chen@linux.dev

On Fri, Mar 13, 2026 at 12:52:23PM +0800, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    8004279c41ad Merge tag 'nfs-for-7.0-2' of git://git.linux-..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=1593c416580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=ccef46afa67b2b19
> dashboard link: https://syzkaller.appspot.com/bug?extid=3d8bc31c45e11450f24c
> compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=172d1416580000
> 
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-8004279c.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/f56a78af5be3/vmlinux-8004279c.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/89a6ba48229d/bzImage-8004279c.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+3d8bc31c45e11450f24c@syzkaller.appspotmail.com
> 
> Oops: general protection fault, probably for non-canonical address 0xe000080fee63d21a: 0000 [#1] SMP KASAN NOPTI
> KASAN: probably user-memory-access in range [0x0000607f731e90d0-0x0000607f731e90d7]
> CPU: 0 UID: 0 PID: 54 Comm: kworker/0:2 Not tainted syzkaller #0 PREEMPT(full) 
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> Workqueue: mld mld_ifc_work
> RIP: 0010:bond_header_create+0x150/0x300 drivers/net/bonding/bond_main.c:1524
> Code: e8 25 bd 59 fb 45 85 f6 0f 84 a5 00 00 00 e8 d7 b8 59 fb eb 05 e8 d0 b8 59 fb 48 85 ed 0f 84 89 00 00 00 48 89 e8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 ef e8 71 81 c5 fb 48 8b 6d 00 4c 8d 75
> RSP: 0018:ffffc90000b0f600 EFLAGS: 00010202
> RAX: 00000c0fee63d21a RBX: ffffffff866bf37b RCX: ffff888000c524c0
> RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
> RBP: 0000607f731e90d0 R08: ffffffff866bf37b R09: ffffffff8e75e420
> R10: dffffc0000000000 R11: ffffffff866bf340 R12: 00000000000086dd
> R13: ffff8880127763c0 R14: 0000000000000001 R15: dffffc0000000000
> FS:  0000000000000000(0000) GS:ffff88808ca55000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f2fbfe3ff8c CR3: 0000000012645000 CR4: 0000000000352ef0
> Call Trace:
>  <TASK>
>  dev_hard_header include/linux/netdevice.h:3439 [inline]
>  neigh_connected_output+0x286/0x460 net/core/neighbour.c:1644
>  __ip6_finish_output net/ipv6/ip6_output.c:-1 [inline]
>  ip6_finish_output+0x2e5/0x740 net/ipv6/ip6_output.c:219
>  NF_HOOK_COND include/linux/netfilter.h:307 [inline]
>  ip6_output+0x340/0x550 net/ipv6/ip6_output.c:246
>  dst_output include/net/dst.h:470 [inline]
>  NF_HOOK+0x177/0x4f0 include/linux/netfilter.h:318
>  mld_sendpack+0x8b4/0xe40 net/ipv6/mcast.c:1855
>  mld_send_cr net/ipv6/mcast.c:2154 [inline]
>  mld_ifc_work+0x835/0xe70 net/ipv6/mcast.c:2693
>  process_one_work kernel/workqueue.c:3275 [inline]
>  process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358
>  worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439
>  kthread+0x388/0x470 kernel/kthread.c:436
>  ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:bond_header_create+0x150/0x300 drivers/net/bonding/bond_main.c:1524
> Code: e8 25 bd 59 fb 45 85 f6 0f 84 a5 00 00 00 e8 d7 b8 59 fb eb 05 e8 d0 b8 59 fb 48 85 ed 0f 84 89 00 00 00 48 89 e8 48 c1 e8 03 <42> 80 3c 38 00 74 08 48 89 ef e8 71 81 c5 fb 48 8b 6d 00 4c 8d 75
> RSP: 0018:ffffc90000b0f600 EFLAGS: 00010202
> RAX: 00000c0fee63d21a RBX: ffffffff866bf37b RCX: ffff888000c524c0
> RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
> RBP: 0000607f731e90d0 R08: ffffffff866bf37b R09: ffffffff8e75e420
> R10: dffffc0000000000 R11: ffffffff866bf340 R12: 00000000000086dd
> R13: ffff8880127763c0 R14: 0000000000000001 R15: dffffc0000000000
> FS:  0000000000000000(0000) GS:ffff88808ca55000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000055e232d92000 CR3: 000000000e54c000 CR4: 0000000000352ef0
> ----------------
> Code disassembly (best guess):
>    0:	e8 25 bd 59 fb       	call   0xfb59bd2a
>    5:	45 85 f6             	test   %r14d,%r14d
>    8:	0f 84 a5 00 00 00    	je     0xb3
>    e:	e8 d7 b8 59 fb       	call   0xfb59b8ea
>   13:	eb 05                	jmp    0x1a
>   15:	e8 d0 b8 59 fb       	call   0xfb59b8ea
>   1a:	48 85 ed             	test   %rbp,%rbp
>   1d:	0f 84 89 00 00 00    	je     0xac
>   23:	48 89 e8             	mov    %rbp,%rax
>   26:	48 c1 e8 03          	shr    $0x3,%rax
> * 2a:	42 80 3c 38 00       	cmpb   $0x0,(%rax,%r15,1) <-- trapping instruction
>   2f:	74 08                	je     0x39
>   31:	48 89 ef             	mov    %rbp,%rdi
>   34:	e8 71 81 c5 fb       	call   0xfbc581aa
>   39:	48 8b 6d 00          	mov    0x0(%rbp),%rbp
>   3d:	4c                   	rex.WR
>   3e:	8d                   	.byte 0x8d
>   3f:	75                   	.byte 0x75
> 
> 
> ---
> 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 syzkaller@googlegroups.com.
> 
> syzbot will keep track of this issue. See:
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> 
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
> 
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
> 
> If you want to overwrite report's subsystems, reply with:
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> 
> If the report is a duplicate of another one, reply with:
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> 
> If you want to undo deduplication, reply with:
> #syz undup



#syz test

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 707419270ebf..47a16117190d 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1518,6 +1518,9 @@ static int bond_header_create(struct sk_buff *skb, struct net_device *bond_dev,
        struct slave *slave;
        int ret = 0;

+       /* debug: team ? */
+       pr_err("bond_header_create: dev=%s\n", bond_dev->name);
+
        rcu_read_lock();
        slave = rcu_dereference(bond->curr_active_slave);
        if (slave) {