linux-kernel - [syzbot] [net?] general protection fault in mld_clear

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Message-ID: <681c07a1.050a0220.a19a9.007c.GAE@google.com>
Date: Wed, 07 May 2025 18:23:45 -0700
From: syzbot <syzbot+888c7330963d4b45da35@...kaller.appspotmail.com>
To: davem@...emloft.net, dsahern@...nel.org, edumazet@...gle.com, 
	horms@...nel.org, kuba@...nel.org, linux-kernel@...r.kernel.org, 
	netdev@...r.kernel.org, pabeni@...hat.com, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [net?] general protection fault in mld_clear_delrec

Hello,

syzbot found the following issue on:

HEAD commit:    92a09c47464d Linux 6.15-rc5
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=15b23b68580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b39cb28b0a399ed3
dashboard link: https://syzkaller.appspot.com/bug?extid=888c7330963d4b45da35
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bb9b7be3962f/disk-92a09c47.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/d4048c02a409/vmlinux-92a09c47.xz
kernel image: https://storage.googleapis.com/syzbot-assets/f1a81e88c04e/bzImage-92a09c47.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+888c7330963d4b45da35@...kaller.appspotmail.com

veth1_vlan: left promiscuous mode
veth0_vlan: left promiscuous mode
team0 (unregistering): Port device team_slave_1 removed
team0 (unregistering): Port device team_slave_0 removed
Oops: general protection fault, probably for non-canonical address 0xdffffc001ffee000: 0000 [#1] SMP KASAN NOPTI
KASAN: probably user-memory-access in range [0x00000000fff70000-0x00000000fff70007]
CPU: 0 UID: 0 PID: 13 Comm: kworker/u8:1 Not tainted 6.15.0-rc5-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/29/2025
Workqueue: netns cleanup_net
RIP: 0010:mld_clear_delrec+0x2a6/0x640 net/ipv6/mcast.c:838
Code: 20 00 0f 85 91 03 00 00 49 8b 5d 28 49 c7 45 28 00 00 00 00 48 85 db 75 37 e9 d4 00 00 00 e8 21 86 96 f7 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 39 03 00 00 48 8b 2b 48 8d 7b 30 48 89 de e8
RSP: 0018:ffffc900001275f8 EFLAGS: 00010206
RAX: 000000001ffee000 RBX: 00000000fff70000 RCX: ffffffff8a24ad36
RDX: ffff88801ca80000 RSI: ffffffff8a24accf RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff888033bf3c00 R14: ffff88805babf000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8881249df000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f87f8f59348 CR3: 000000000e180000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 ipv6_mc_destroy_dev+0x49/0x690 net/ipv6/mcast.c:2842
 addrconf_ifdown.isra.0+0x13ef/0x1a90 net/ipv6/addrconf.c:3997
 addrconf_notify+0x220/0x19e0 net/ipv6/addrconf.c:3777
 notifier_call_chain+0xb9/0x410 kernel/notifier.c:85
 call_netdevice_notifiers_info+0xbe/0x140 net/core/dev.c:2176
 call_netdevice_notifiers_extack net/core/dev.c:2214 [inline]
 call_netdevice_notifiers net/core/dev.c:2228 [inline]
 unregister_netdevice_many_notify+0xf9a/0x26f0 net/core/dev.c:11982
 unregister_netdevice_many net/core/dev.c:12046 [inline]
 default_device_exit_batch+0x853/0xaf0 net/core/dev.c:12538
 ops_exit_list+0x128/0x180 net/core/net_namespace.c:177
 cleanup_net+0x5c1/0xb30 net/core/net_namespace.c:654
 process_one_work+0x9cc/0x1b70 kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3319 [inline]
 worker_thread+0x6c8/0xf10 kernel/workqueue.c:3400
 kthread+0x3c2/0x780 kernel/kthread.c:464
 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:153
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:mld_clear_delrec+0x2a6/0x640 net/ipv6/mcast.c:838
Code: 20 00 0f 85 91 03 00 00 49 8b 5d 28 49 c7 45 28 00 00 00 00 48 85 db 75 37 e9 d4 00 00 00 e8 21 86 96 f7 48 89 d8 48 c1 e8 03 <42> 80 3c 20 00 0f 85 39 03 00 00 48 8b 2b 48 8d 7b 30 48 89 de e8
RSP: 0018:ffffc900001275f8 EFLAGS: 00010206
RAX: 000000001ffee000 RBX: 00000000fff70000 RCX: ffffffff8a24ad36
RDX: ffff88801ca80000 RSI: ffffffff8a24accf RDI: 0000000000000005
RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000
R13: ffff888033bf3c00 R14: ffff88805babf000 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff888124adf000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe3317d4800 CR3: 000000000e180000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	20 00                	and    %al,(%rax)
   2:	0f 85 91 03 00 00    	jne    0x399
   8:	49 8b 5d 28          	mov    0x28(%r13),%rbx
   c:	49 c7 45 28 00 00 00 	movq   $0x0,0x28(%r13)
  13:	00
  14:	48 85 db             	test   %rbx,%rbx
  17:	75 37                	jne    0x50
  19:	e9 d4 00 00 00       	jmp    0xf2
  1e:	e8 21 86 96 f7       	call   0xf7968644
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 20 00       	cmpb   $0x0,(%rax,%r12,1) <-- trapping instruction
  2f:	0f 85 39 03 00 00    	jne    0x36e
  35:	48 8b 2b             	mov    (%rbx),%rbp
  38:	48 8d 7b 30          	lea    0x30(%rbx),%rdi
  3c:	48 89 de             	mov    %rbx,%rsi
  3f:	e8                   	.byte 0xe8


---
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