[syzbot] [net?] general protection fault in bond_header_create

[syzbot] [net?] general protection fault in bond_header_create

[syzbot]

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:
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If you want syzbot to run the reproducer, reply with:
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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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(See the list of subsystem names on the web dashboard)

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

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

[Eric Dumazet]

On Fri, Mar 13, 2026 at 8:52 PM syzbot
<syzbot+3d8bc31c45e11450f24c@syzkaller.appspotmail.com> 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:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
> 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:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup

I am suspecting.

Can you take a look ?

Thanks.

commit 950803f7254721c1c15858fbbfae3deaaeeecb11
Author: Jiayuan Chen <jiayuan.chen@shopee.com>
Date:   Fri Mar 6 10:15:07 2026 +0800

    bonding: fix type confusion in bond_setup_by_slave()

Forwarded: [PATCH] bonding: debug: add printk to bond_header_create

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] bonding: debug: add printk to bond_header_create
Author: kartikey406@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


Add temporary debug printks to identify which pointer is corrupted
in bond_header_create() causing a general protection fault.

Reported-by: syzbot+3d8bc31c45e11450f24c@syzkaller.appspotmail.com
---
 drivers/net/bonding/bond_main.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 707419270ebf..807ab8784116 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1520,7 +1520,12 @@ static int bond_header_create(struct sk_buff *skb, struct net_device *bond_dev,
 
 	rcu_read_lock();
 	slave = rcu_dereference(bond->curr_active_slave);
+	pr_err("bond: curr_active_slave raw=%px\n", 
+                rcu_access_pointer(bond->curr_active_slave));
 	if (slave) {
+		pr_err("bond: slave=%px\n", slave);
+		pr_err("bond: slave->dev=%px\n", slave->dev);
+		pr_err("bond: slave->dev->header_ops=%px\n", slave->dev->header_ops);
 		slave_ops = READ_ONCE(slave->dev->header_ops);
 		if (slave_ops && slave_ops->create)
 			ret = slave_ops->create(skb, slave->dev,
-- 
2.43.0

Forwarded: [PATCH] bonding: debug: add printk to bond_header_create

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] bonding: debug: add printk to bond_header_create
Author: kartikey406@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


Add temporary debug printks to identify which pointer is corrupted
in bond_header_create() causing a general protection fault.

Reported-by: syzbot+3d8bc31c45e11450f24c@syzkaller.appspotmail.com
---
 drivers/net/bonding/bond_main.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 707419270ebf..807ab8784116 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1520,7 +1520,12 @@ static int bond_header_create(struct sk_buff *skb, struct net_device *bond_dev,
 
 	rcu_read_lock();
 	slave = rcu_dereference(bond->curr_active_slave);
+	pr_err("bond: curr_active_slave raw=%px\n", 
+                rcu_access_pointer(bond->curr_active_slave));
 	if (slave) {
+		pr_err("bond: slave=%px\n", slave);
+		pr_err("bond: slave->dev=%px\n", slave->dev);
+		pr_err("bond: slave->dev->header_ops=%px\n", slave->dev->header_ops);
 		slave_ops = READ_ONCE(slave->dev->header_ops);
 		if (slave_ops && slave_ops->create)
 			ret = slave_ops->create(skb, slave->dev,
-- 
2.43.0

Forwarded: [PATCH] bonding: debug: add printk to bond_header_create

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

Subject: [PATCH] bonding: debug: add printk to bond_header_create
Author: kartikey406@gmail.com

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master


Add temporary debug printks to identify which pointer is corrupted
in bond_header_create() causing a general protection fault.

Reported-by: syzbot+3d8bc31c45e11450f24c@syzkaller.appspotmail.com
---
 drivers/net/bonding/bond_main.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 707419270ebf..807ab8784116 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1520,7 +1520,12 @@ static int bond_header_create(struct sk_buff *skb, struct net_device *bond_dev,
 
 	rcu_read_lock();
 	slave = rcu_dereference(bond->curr_active_slave);
+	pr_err("bond: curr_active_slave raw=%px\n", 
+                rcu_access_pointer(bond->curr_active_slave));
 	if (slave) {
+		pr_err("bond: slave=%px\n", slave);
+		pr_err("bond: slave->dev=%px\n", slave->dev);
+		pr_err("bond: slave->dev->header_ops=%px\n", slave->dev->header_ops);
 		slave_ops = READ_ONCE(slave->dev->header_ops);
 		if (slave_ops && slave_ops->create)
 			ret = slave_ops->create(skb, slave->dev,
-- 
2.43.0

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

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com.

***

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:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> 
> 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:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
> 
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
> 
> 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) {

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

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
lost connection to test machine



Tested on:

commit:         1c9982b4 Merge tag 'drm-fixes-2026-03-14' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14395d52580000
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
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12e23c16580000

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

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to copy syz-execprog to VM: failed to run ["scp" "-P" "29478" "-F" "/dev/null" "-o" "UserKnownHostsFile=/dev/null" "-o" "IdentitiesOnly=yes" "-o" "BatchMode=yes" "-o" "StrictHostKeyChecking=no" "-o" "ConnectTimeout=10" "/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/bin/linux_amd64/syz-execprog" "root@localhost:/syz-execprog"]: exit status 255



syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build1111839217=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs/linux/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.26.0'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at 2f7f359d8a4d
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=2f7f359d8a4db30d79a33f1bbc17a331b1eb58dd -X github.com/google/syzkaller/prog.gitRevisionDate=20260312-214211"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=2f7f359d8a4db30d79a33f1bbc17a331b1eb58dd -X github.com/google/syzkaller/prog.gitRevisionDate=20260312-214211"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=2f7f359d8a4db30d79a33f1bbc17a331b1eb58dd -X github.com/google/syzkaller/prog.gitRevisionDate=20260312-214211"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -o ./bin/linux_amd64/syz-executor executor/executor.cc \
	-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"2f7f359d8a4db30d79a33f1bbc17a331b1eb58dd\"
/usr/bin/ld: /tmp/ccwvqbK3.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x386): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null



Tested on:

commit:         1c9982b4 Merge tag 'drm-fixes-2026-03-14' of https://g..
git tree:       upstream
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
patch:          https://syzkaller.appspot.com/x/patch.diff?x=153f1602580000

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

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
lost connection to test machine



Tested on:

commit:         1c9982b4 Merge tag 'drm-fixes-2026-03-14' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14df1602580000
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
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1267a216580000

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

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

lost connection to test machine



syzkaller login: qemu-system-x86_64: ahci: PRDT length for NCQ command (0x0) is smaller than the requested size (0x8e000)
Warning: Permanently added '[localhost]:18996' (ED25519) to the list of known hosts.
[   97.289256][   T10] cfg80211: failed to load regulatory.db
[  152.340372][ T1011] ata1.00: exception Emask 0x0 SAct 0x4000 SErr 0x0 action 0x6 frozen
[  152.344761][ T1011] ata1.00: failed command: WRITE FPDMA QUEUED
[  152.347836][ T1011] ata1.00: cmd 61/70:70:b6:54:04/04:00:00:00:00/40 tag 14 ncq dma 581632 out
[  152.347836][ T1011]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[  152.357188][ T1011] ata1.00: status: { DRDY }
[  152.360133][ T1011] ata1: hard resetting link
[  152.682867][ T1011] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[  152.688365][ T1011] ata1.00: configured for UDMA/100
[  152.691802][ T1011] ata1: EH complete
qemu-system-x86_64: ahci: PRDT length for NCQ command (0x0) is smaller than the requested size (0x83000)
2026/03/14 02:48:08 parsed 1 programs
[  157.947149][ T5334] cgroup: Unknown subsys name 'net'
[  157.998795][ T5334] cgroup: Unknown subsys name 'cpuset'
[  158.005626][ T5334] cgroup: Unknown subsys name 'rlimit'
[  209.923844][ T1316] ieee802154 phy0 wpan0: encryption failed: -22
[  209.927618][ T1316] ieee802154 phy1 wpan1: encryption failed: -22
[  218.260125][ T1011] ata1.00: NCQ disabled due to excessive errors
[  218.263261][ T1011] ata1.00: exception Emask 0x0 SAct 0x4000 SErr 0x0 action 0x6 frozen
[  218.267800][ T1011] ata1.00: failed command: WRITE FPDMA QUEUED
[  218.271402][ T1011] ata1.00: cmd 61/18:70:1e:9d:05/04:00:00:00:00/40 tag 14 ncq dma 536576 out
[  218.271402][ T1011]          res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
[  218.280859][ T1011] ata1.00: status: { DRDY }
[  218.283018][ T1011] ata1: hard resetting link
[  218.602968][ T1011] ata1: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
[  218.608098][ T1011] ata1.00: configured for UDMA/100
[  218.611748][ T1011] ata1: EH complete
qemu-system-x86_64: hw/ide/core.c:934: ide_dma_cb: Assertion `prep_size >= 0 && prep_size <= n * 512' failed.
Connection to localhost closed by remote host.


syzkaller build log:
go env (err=<nil>)
AR='ar'
CC='gcc'
CGO_CFLAGS='-O2 -g'
CGO_CPPFLAGS=''
CGO_CXXFLAGS='-O2 -g'
CGO_ENABLED='1'
CGO_FFLAGS='-O2 -g'
CGO_LDFLAGS='-O2 -g'
CXX='g++'
GCCGO='gccgo'
GO111MODULE='auto'
GOAMD64='v1'
GOARCH='amd64'
GOAUTH='netrc'
GOBIN=''
GOCACHE='/syzkaller/.cache/go-build'
GOCACHEPROG=''
GODEBUG=''
GOENV='/syzkaller/.config/go/env'
GOEXE=''
GOEXPERIMENT=''
GOFIPS140='off'
GOFLAGS=''
GOGCCFLAGS='-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -ffile-prefix-map=/tmp/go-build4127251169=/tmp/go-build -gno-record-gcc-switches'
GOHOSTARCH='amd64'
GOHOSTOS='linux'
GOINSECURE=''
GOMOD='/syzkaller/jobs/linux/gopath/src/github.com/google/syzkaller/go.mod'
GOMODCACHE='/syzkaller/jobs/linux/gopath/pkg/mod'
GONOPROXY=''
GONOSUMDB=''
GOOS='linux'
GOPATH='/syzkaller/jobs/linux/gopath'
GOPRIVATE=''
GOPROXY='https://proxy.golang.org,direct'
GOROOT='/usr/local/go'
GOSUMDB='sum.golang.org'
GOTELEMETRY='local'
GOTELEMETRYDIR='/syzkaller/.config/go/telemetry'
GOTMPDIR=''
GOTOOLCHAIN='auto'
GOTOOLDIR='/usr/local/go/pkg/tool/linux_amd64'
GOVCS=''
GOVERSION='go1.26.0'
GOWORK=''
PKG_CONFIG='pkg-config'

git status (err=<nil>)
HEAD detached at 2f7f359d8a4d
nothing to commit, working tree clean


tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
go list -f '{{.Stale}}' -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=2f7f359d8a4db30d79a33f1bbc17a331b1eb58dd -X github.com/google/syzkaller/prog.gitRevisionDate=20260312-214211"  ./sys/syz-sysgen | grep -q false || go install -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=2f7f359d8a4db30d79a33f1bbc17a331b1eb58dd -X github.com/google/syzkaller/prog.gitRevisionDate=20260312-214211"  ./sys/syz-sysgen
make .descriptions
tput: No value for $TERM and no -T specified
tput: No value for $TERM and no -T specified
Makefile:31: run command via tools/syz-env for best compatibility, see:
Makefile:32: https://github.com/google/syzkaller/blob/master/docs/contributing.md#using-syz-env
bin/syz-sysgen
touch .descriptions
GOOS=linux GOARCH=amd64 go build -ldflags="-s -w -X github.com/google/syzkaller/prog.GitRevision=2f7f359d8a4db30d79a33f1bbc17a331b1eb58dd -X github.com/google/syzkaller/prog.gitRevisionDate=20260312-214211"  -o ./bin/linux_amd64/syz-execprog github.com/google/syzkaller/tools/syz-execprog
mkdir -p ./bin/linux_amd64
g++ -o ./bin/linux_amd64/syz-executor executor/executor.cc \
	-m64 -O2 -pthread -Wall -Werror -Wparentheses -Wunused-const-variable -Wframe-larger-than=16384 -Wno-stringop-overflow -Wno-array-bounds -Wno-format-overflow -Wno-unused-but-set-variable -Wno-unused-command-line-argument -static-pie -std=c++17 -I. -Iexecutor/_include   -DGOOS_linux=1 -DGOARCH_amd64=1 \
	-DHOSTGOOS_linux=1 -DGIT_REVISION=\"2f7f359d8a4db30d79a33f1bbc17a331b1eb58dd\"
/usr/bin/ld: /tmp/ccFlVss0.o: in function `Connection::Connect(char const*, char const*)':
executor.cc:(.text._ZN10Connection7ConnectEPKcS1_[_ZN10Connection7ConnectEPKcS1_]+0x386): warning: Using 'gethostbyname' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
./tools/check-syzos.sh 2>/dev/null



Tested on:

commit:         1c9982b4 Merge tag 'drm-fixes-2026-03-14' of https://g..
git tree:       upstream
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
patch:          https://syzkaller.appspot.com/x/patch.diff?x=15f61d4a580000