[syzbot] [net?] WARNING in rtnl_dellink (3)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 048c796beb6e ipv6: adjust ndisc_is_useropt() to also retur..
git tree: net
console+strace: https://syzkaller.appspot.com/x/log.txt?x=15b02135a80000
kernel config: https://syzkaller.appspot.com/x/.config?x=fa5bd4cd5ab6259d
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4f06495414e92701d5
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1700ccaba80000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158dfa43a80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/bf6b84b5998f/disk-048c796b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4000dee89ebe/vmlinux-048c796b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b700ee9bd306/bzImage-048c796b.xz

The issue was bisected to:

commit 718cb09aaa6fa78cc8124e9517efbc6c92665384
Author: Vlad Buslov <vla...@nvidia.com>
Date: Tue Aug 8 09:35:21 2023 +0000

vlan: Fix VLAN 0 memory leak

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1369e31da80000
final oops: https://syzkaller.appspot.com/x/report.txt?x=10e9e31da80000
console output: https://syzkaller.appspot.com/x/log.txt?x=1769e31da80000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+4b4f06...@syzkaller.appspotmail.com
Fixes: 718cb09aaa6f ("vlan: Fix VLAN 0 memory leak")

------------[ cut here ]------------
WARNING: CPU: 0 PID: 5090 at net/core/dev.c:10876 unregister_netdevice_many_notify+0x14d8/0x19a0 net/core/dev.c:10876
Modules linked in:
CPU: 0 PID: 5090 Comm: syz-executor155 Not tainted 6.5.0-rc4-syzkaller-00248-g048c796beb6e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
RIP: 0010:unregister_netdevice_many_notify+0x14d8/0x19a0 net/core/dev.c:10876
Code: b4 1a 00 00 48 c7 c6 e0 18 81 8b 48 c7 c7 20 19 81 8b c6 05 ab 19 6c 06 01 e8 b4 22 23 f9 0f 0b e9 64 f7 ff ff e8 68 60 5c f9 <0f> 0b e9 3b f7 ff ff e8 fc 68 b0 f9 e9 fc ec ff ff 4c 89 e7 e8 4f
RSP: 0018:ffffc90003c4f158 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000028921a01 RCX: 0000000000000000
RDX: ffff888020503b80 RSI: ffffffff8829a7b8 RDI: 0000000000000001
RBP: ffff88807d990000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880274efe00
R13: 0000000000000000 R14: 0000000000000002 R15: ffff8880274efe00
FS: 0000555555fb0380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffdeffb1328 CR3: 000000002a3a9000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
rtnl_delete_link net/core/rtnetlink.c:3214 [inline]
rtnl_dellink+0x3c1/0xae0 net/core/rtnetlink.c:3266
rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6428
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:748
____sys_sendmsg+0x6ac/0x940 net/socket.c:2494
___sys_sendmsg+0x135/0x1d0 net/socket.c:2548
__sys_sendmsg+0x117/0x1e0 net/socket.c:2577
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f2876b4cce9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 d1 19 00 00 90 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdeffb1428 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f2876b4cce9
RDX: 0000000000000000 RSI: 00000000200002c0 RDI: 0000000000000004
RBP: 00000000000f4240 R08: 0000000100000000 R09: 0000000100000000
R10: 0000000100000000 R11: 0000000000000246 R12: 00007ffdeffb1480
R13: 00000000000157a9 R14: 00007ffdeffb144c R15: 0000000000000003
</TASK>


---
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 syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
For information about bisection process see: https://goo.gl/tpsmEJ#bisection

If the bug is already fixed, 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 change bug's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the bug is a duplicate of another bug, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[Hillf Danton]

On Fri, 11 Aug 2023 06:57:06 -0700

> HEAD commit: 048c796beb6e ipv6: adjust ndisc_is_useropt() to also retur..
> git tree: net

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158dfa43a80000

Unregister netdev in addition to vlan devices.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git 048c796beb6e

--- x/net/8021q/vlan.c
+++ y/net/8021q/vlan.c
@@ -486,6 +486,7 @@ static int vlan_device_event(struct noti
break;
}
unregister_netdevice_many(&list);
+ unregister_netdevice(dev);
break;

case NETDEV_PRE_TYPE_CHANGE:
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
kernel BUG in vlan_device_event

------------[ cut here ]------------
kernel BUG at net/core/dev.c:10817!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 0 PID: 5776 Comm: syz-executor.0 Not tainted 6.5.0-rc4-syzkaller-00248-g048c796beb6e-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023

RIP: 0010:unregister_netdevice_many_notify+0x308/0x19a0 net/core/dev.c:10817
Code: 4c 89 fa 48 c7 c6 a0 3e 81 8b 48 c7 c7 40 9a a6 8e e8 3c 49 22 fc e9 0f ff ff ff 4d 8d 67 60 49 8d 5f 68 eb 8b e8 38 72 5c f9 <0f> 0b e8 31 72 5c f9 48 8b 14 24 48 b8 00 00 00 00 00 fc ff df 48
RSP: 0018:ffffc9000aaeee00 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
RDX: ffff888022c55940 RSI: ffffffff882995e8 RDI: 0000000000000001
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000002 R11: ffffffff8a40008b R12: ffff88801ed42060
R13: ffffc9000aaeef40 R14: ffffc9000aaeeee0 R15: ffff88801ed42000
FS: 00007f2a6ff536c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000020000040 CR3: 000000002a534000 CR4: 0000000000350ef0
Call Trace:
<TASK>
unregister_netdevice_many net/core/dev.c:10906 [inline]
unregister_netdevice_queue+0x2e5/0x3c0 net/core/dev.c:10786
unregister_netdevice include/linux/netdevice.h:3112 [inline]
vlan_device_event+0x17e2/0x2070 net/8021q/vlan.c:489
notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93
call_netdevice_notifiers_info+0xb9/0x130 net/core/dev.c:1962
call_netdevice_notifiers_extack net/core/dev.c:2000 [inline]
call_netdevice_notifiers net/core/dev.c:2014 [inline]
unregister_netdevice_many_notify+0x82b/0x19a0 net/core/dev.c:10850

rtnl_delete_link net/core/rtnetlink.c:3214 [inline]
rtnl_dellink+0x3c1/0xae0 net/core/rtnetlink.c:3266
rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6428
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:748
____sys_sendmsg+0x6ac/0x940 net/socket.c:2494
___sys_sendmsg+0x135/0x1d0 net/socket.c:2548
__sys_sendmsg+0x117/0x1e0 net/socket.c:2577
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7f2a6f27cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2a6ff530c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f2a6f39bf80 RCX: 00007f2a6f27cae9
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 00007f2a6f2c847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000004d R14: 00007f2a6f39bf80 R15: 00007ffdb5205158
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:unregister_netdevice_many_notify+0x308/0x19a0 net/core/dev.c:10817
Code: 4c 89 fa 48 c7 c6 a0 3e 81 8b 48 c7 c7 40 9a a6 8e e8 3c 49 22 fc e9 0f ff ff ff 4d 8d 67 60 49 8d 5f 68 eb 8b e8 38 72 5c f9 <0f> 0b e8 31 72 5c f9 48 8b 14 24 48 b8 00 00 00 00 00 fc ff df 48
RSP: 0018:ffffc9000aaeee00 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000002 RCX: 0000000000000000
RDX: ffff888022c55940 RSI: ffffffff882995e8 RDI: 0000000000000001
RBP: dffffc0000000000 R08: 0000000000000001 R09: 0000000000000001
R10: 0000000000000002 R11: ffffffff8a40008b R12: ffff88801ed42060
R13: ffffc9000aaeef40 R14: ffffc9000aaeeee0 R15: ffff88801ed42000
FS: 00007f2a6ff536c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000020000040 CR3: 000000002a534000 CR4: 0000000000350ef0


Tested on:

commit: 048c796b ipv6: adjust ndisc_is_useropt() to also retur..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git
console output: https://syzkaller.appspot.com/x/log.txt?x=11a8e003a80000

kernel config: https://syzkaller.appspot.com/x/.config?x=fa5bd4cd5ab6259d
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4f06495414e92701d5
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=12fb00ada80000

[Hillf Danton]

On Fri, 11 Aug 2023 06:57:06 -0700

> HEAD commit: 048c796beb6e ipv6: adjust ndisc_is_useropt() to also retur..
> git tree: net

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158dfa43a80000

Add no vlan dev to vlan dev.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git 048c796beb6e

--- x/net/8021q/vlan.c
+++ y/net/8021q/vlan.c

@@ -614,6 +614,9 @@ static int vlan_ioctl_handler(struct net
break;

case ADD_VLAN_CMD:
+ err = -EINVAL;
+ if (is_vlan_dev(dev))
+ break;
err = -EPERM;
if (!ns_capable(net->user_ns, CAP_NET_ADMIN))
break;
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:

WARNING in rtnl_dellink

------------[ cut here ]------------
WARNING: CPU: 1 PID: 5782 at net/core/dev.c:10876 unregister_netdevice_many_notify+0x14d8/0x19a0 net/core/dev.c:10876
Modules linked in:
CPU: 1 PID: 5782 Comm: syz-executor.0 Not tainted 6.5.0-rc4-syzkaller-00248-g048c796beb6e-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023

RIP: 0010:unregister_netdevice_many_notify+0x14d8/0x19a0 net/core/dev.c:10876
Code: b4 1a 00 00 48 c7 c6 e0 18 81 8b 48 c7 c7 20 19 81 8b c6 05 ab 19 6c 06 01 e8 b4 22 23 f9 0f 0b e9 64 f7 ff ff e8 68 60 5c f9 <0f> 0b e9 3b f7 ff ff e8 fc 68 b0 f9 e9 fc ec ff ff 4c 89 e7 e8 4f

RSP: 0018:ffffc90006607158 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000020f52401 RCX: 0000000000000000
RDX: ffff88807e16bb80 RSI: ffffffff8829a7b8 RDI: 0000000000000001
RBP: ffff88802c5be000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000094000 R12: ffff88802a2c6b00
R13: 0000000000000000 R14: 0000000000000002 R15: ffff88802a2c6b00
FS: 00007f3f392a36c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000020000040 CR3: 000000002a22d000 CR4: 0000000000350ee0
Call Trace:
<TASK>

rtnl_delete_link net/core/rtnetlink.c:3214 [inline]
rtnl_dellink+0x3c1/0xae0 net/core/rtnetlink.c:3266
rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6428
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:748
____sys_sendmsg+0x6ac/0x940 net/socket.c:2494
___sys_sendmsg+0x135/0x1d0 net/socket.c:2548
__sys_sendmsg+0x117/0x1e0 net/socket.c:2577
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7f3f3847cae9

Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007f3f392a30c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f3f3859bf80 RCX: 00007f3f3847cae9

RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003

RBP: 00007f3f384c847a R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 000000000000004d R14: 00007f3f3859bf80 R15: 00007ffe1ecc54b8
</TASK>

Tested on:

commit: 048c796b ipv6: adjust ndisc_is_useropt() to also retur..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git

console output: https://syzkaller.appspot.com/x/log.txt?x=1401a3aba80000

kernel config: https://syzkaller.appspot.com/x/.config?x=fa5bd4cd5ab6259d
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4f06495414e92701d5
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=161a6017a80000

[Hillf Danton]

On Fri, 11 Aug 2023 06:57:06 -0700

> HEAD commit: 048c796beb6e ipv6: adjust ndisc_is_useropt() to also retur..
> git tree: net

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158dfa43a80000

Unregister vlan dev in addition to upper dev.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git 048c796beb6e

--- x/net/8021q/vlan.c
+++ y/net/8021q/vlan.c

@@ -486,6 +486,7 @@ static int vlan_device_event(struct noti
break;
}
unregister_netdevice_many(&list);

+ unregister_vlan_dev(dev, NULL);
break;

case NETDEV_PRE_TYPE_CHANGE:
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:

KASAN: slab-out-of-bounds Read in unregister_vlan_dev

==================================================================
BUG: KASAN: slab-out-of-bounds in unregister_vlan_dev+0x4fa/0x580 net/8021q/vlan.c:92
Read of size 8 at addr ffff88806a042d30 by task syz-executor.0/5775

CPU: 0 PID: 5775 Comm: syz-executor.0 Not tainted 6.5.0-rc4-syzkaller-00248-g048c796beb6e-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023

Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xd9/0x1b0 lib/dump_stack.c:106
print_address_description mm/kasan/report.c:364 [inline]
print_report+0xc4/0x620 mm/kasan/report.c:475
kasan_report+0xda/0x110 mm/kasan/report.c:588
unregister_vlan_dev+0x4fa/0x580 net/8021q/vlan.c:92

vlan_device_event+0x17e2/0x2070 net/8021q/vlan.c:489
notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93
call_netdevice_notifiers_info+0xb9/0x130 net/core/dev.c:1962
call_netdevice_notifiers_extack net/core/dev.c:2000 [inline]
call_netdevice_notifiers net/core/dev.c:2014 [inline]
unregister_netdevice_many_notify+0x82b/0x19a0 net/core/dev.c:10850

rtnl_delete_link net/core/rtnetlink.c:3214 [inline]
rtnl_dellink+0x3c1/0xae0 net/core/rtnetlink.c:3266
rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6428
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:748
____sys_sendmsg+0x6ac/0x940 net/socket.c:2494
___sys_sendmsg+0x135/0x1d0 net/socket.c:2548
__sys_sendmsg+0x117/0x1e0 net/socket.c:2577
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7f2b57e7cae9

Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007f2b58cc50c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f2b57f9bf80 RCX: 00007f2b57e7cae9

RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003

RBP: 00007f2b57ec847a R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 000000000000004d R14: 00007f2b57f9bf80 R15: 00007ffddd57e0c8
</TASK>

Allocated by task 5373:
kasan_save_stack+0x33/0x50 mm/kasan/common.c:45
kasan_set_track+0x25/0x30 mm/kasan/common.c:52
____kasan_kmalloc mm/kasan/common.c:374 [inline]
__kasan_kmalloc+0xa2/0xb0 mm/kasan/common.c:383
kasan_kmalloc include/linux/kasan.h:196 [inline]
__do_kmalloc_node mm/slab_common.c:985 [inline]
__kmalloc_node+0x60/0x100 mm/slab_common.c:992
kmalloc_node include/linux/slab.h:602 [inline]
kvmalloc_node+0x99/0x1a0 mm/util.c:604
kvmalloc include/linux/slab.h:720 [inline]
kvzalloc include/linux/slab.h:728 [inline]
alloc_netdev_mqs+0x9b/0x1240 net/core/dev.c:10594
rtnl_create_link+0xc9c/0xfd0 net/core/rtnetlink.c:3336
rtnl_newlink_create net/core/rtnetlink.c:3462 [inline]
__rtnl_newlink+0x1075/0x18c0 net/core/rtnetlink.c:3689
rtnl_newlink+0x67/0xa0 net/core/rtnetlink.c:3702

rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6428
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:748

__sys_sendto+0x255/0x340 net/socket.c:2134
__do_sys_sendto net/socket.c:2146 [inline]
__se_sys_sendto net/socket.c:2142 [inline]
__x64_sys_sendto+0xe0/0x1b0 net/socket.c:2142

do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff88806a042000
which belongs to the cache kmalloc-cg-4k of size 4096
The buggy address is located 105 bytes to the right of
allocated 3271-byte region [ffff88806a042000, ffff88806a042cc7)

The buggy address belongs to the physical page:
page:ffffea0001a81000 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6a040
head:ffffea0001a81000 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff88802b2789c1
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000010200 ffff88801284f500 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000040004 00000001ffffffff ffff88802b2789c1
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5373, tgid 5373 (syz-executor.0), ts 68111966563, free_ts 44747678296
set_page_owner include/linux/page_owner.h:31 [inline]
post_alloc_hook+0x2d2/0x350 mm/page_alloc.c:1570
prep_new_page mm/page_alloc.c:1577 [inline]
get_page_from_freelist+0x10a9/0x31e0 mm/page_alloc.c:3221
__alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4477
alloc_pages+0x1a9/0x270 mm/mempolicy.c:2292
alloc_slab_page mm/slub.c:1862 [inline]
allocate_slab+0x24e/0x380 mm/slub.c:2009
new_slab mm/slub.c:2062 [inline]
___slab_alloc+0x8bc/0x1570 mm/slub.c:3215
__slab_alloc.constprop.0+0x56/0xa0 mm/slub.c:3314
__slab_alloc_node mm/slub.c:3367 [inline]
slab_alloc_node mm/slub.c:3460 [inline]
__kmem_cache_alloc_node+0x137/0x350 mm/slub.c:3509
__do_kmalloc_node mm/slab_common.c:984 [inline]
__kmalloc_node_track_caller+0x4d/0x100 mm/slab_common.c:1005
kmemdup+0x29/0x60 mm/util.c:131
kmemdup include/linux/fortify-string.h:765 [inline]
__addrconf_sysctl_register+0xc2/0x3f0 net/ipv6/addrconf.c:7076
addrconf_sysctl_register net/ipv6/addrconf.c:7141 [inline]
addrconf_sysctl_register+0x133/0x1d0 net/ipv6/addrconf.c:7130
ipv6_add_dev+0x9ee/0x13d0 net/ipv6/addrconf.c:449
addrconf_notify+0x566/0x1940 net/ipv6/addrconf.c:3557

notifier_call_chain+0xb6/0x3b0 kernel/notifier.c:93
call_netdevice_notifiers_info+0xb9/0x130 net/core/dev.c:1962

page last free stack trace:
reset_page_owner include/linux/page_owner.h:24 [inline]
free_pages_prepare mm/page_alloc.c:1161 [inline]
free_unref_page_prepare+0x508/0xb90 mm/page_alloc.c:2348
free_unref_page+0x33/0x3b0 mm/page_alloc.c:2443
vfree+0x181/0x7a0 mm/vmalloc.c:2842
kcov_put kernel/kcov.c:429 [inline]
kcov_put+0x26/0x40 kernel/kcov.c:425
kcov_close+0x10/0x20 kernel/kcov.c:525
__fput+0x3fd/0xac0 fs/file_table.c:384
task_work_run+0x14d/0x240 kernel/task_work.c:179
exit_task_work include/linux/task_work.h:38 [inline]
do_exit+0xa99/0x2a20 kernel/exit.c:874
do_group_exit+0xd4/0x2a0 kernel/exit.c:1024
get_signal+0x23ea/0x2770 kernel/signal.c:2881
arch_do_signal_or_restart+0x89/0x5f0 arch/x86/kernel/signal.c:308
exit_to_user_mode_loop kernel/entry/common.c:168 [inline]
exit_to_user_mode_prepare+0x11f/0x240 kernel/entry/common.c:204
__syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:297
do_syscall_64+0x44/0xb0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
ffff88806a042c00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
ffff88806a042c80: 00 00 00 00 00 00 00 00 07 fc fc fc fc fc fc fc
>ffff88806a042d00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
^
ffff88806a042d80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88806a042e00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Tested on:

commit: 048c796b ipv6: adjust ndisc_is_useropt() to also retur..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git

console output: https://syzkaller.appspot.com/x/log.txt?x=142903aba80000

kernel config: https://syzkaller.appspot.com/x/.config?x=fa5bd4cd5ab6259d
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4f06495414e92701d5
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=16e4d78ba80000

[Hillf Danton]

On Fri, 11 Aug 2023 06:57:06 -0700

> HEAD commit: 048c796beb6e ipv6: adjust ndisc_is_useropt() to also retur..
> git tree: net

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158dfa43a80000

Delete vid after unregistering vlan devices.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git 048c796beb6e

--- x/net/8021q/vlan.c
+++ y/net/8021q/vlan.c

@@ -384,8 +384,6 @@ static int vlan_device_event(struct noti
dev->name);
vlan_vid_add(dev, htons(ETH_P_8021Q), 0);
}
- if (event == NETDEV_DOWN)
- vlan_vid_del(dev, htons(ETH_P_8021Q), 0);

vlan_info = rtnl_dereference(dev->vlan_info);
if (!vlan_info)
@@ -522,6 +520,8 @@ static int vlan_device_event(struct noti
vlan_filter_drop_vids(vlan_info, htons(ETH_P_8021AD));
break;
}
+ if (event == NETDEV_DOWN)
+ vlan_vid_del(dev, htons(ETH_P_8021Q), 0);

out:
return NOTIFY_DONE;
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:

WARNING in rtnl_dellink

------------[ cut here ]------------

WARNING: CPU: 1 PID: 5783 at net/core/dev.c:10876 unregister_netdevice_many_notify+0x14d8/0x19a0 net/core/dev.c:10876
Modules linked in:
CPU: 1 PID: 5783 Comm: syz-executor.0 Not tainted 6.5.0-rc4-syzkaller-00248-g048c796beb6e-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023

RIP: 0010:unregister_netdevice_many_notify+0x14d8/0x19a0 net/core/dev.c:10876
Code: b4 1a 00 00 48 c7 c6 e0 18 81 8b 48 c7 c7 20 19 81 8b c6 05 ab 19 6c 06 01 e8 b4 22 23 f9 0f 0b e9 64 f7 ff ff e8 68 60 5c f9 <0f> 0b e9 3b f7 ff ff e8 fc 68 b0 f9 e9 fc ec ff ff 4c 89 e7 e8 4f

RSP: 0018:ffffc9000594f158 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 000000002b3eb101 RCX: 0000000000000000
RDX: ffff8880244fbb80 RSI: ffffffff8829a7b8 RDI: 0000000000000001
RBP: ffff88801f5cc000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000094000 R12: ffff88802998fa00
R13: 0000000000000000 R14: 0000000000000002 R15: ffff88802998fa00
FS: 00007f7724c956c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000

CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 0000000020000040 CR3: 0000000077189000 CR4: 0000000000350ee0
Call Trace:
<TASK>

rtnl_delete_link net/core/rtnetlink.c:3214 [inline]
rtnl_dellink+0x3c1/0xae0 net/core/rtnetlink.c:3266
rtnetlink_rcv_msg+0x439/0xd30 net/core/rtnetlink.c:6428
netlink_rcv_skb+0x16b/0x440 net/netlink/af_netlink.c:2549
netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]
netlink_unicast+0x539/0x800 net/netlink/af_netlink.c:1365
netlink_sendmsg+0x93c/0xe30 net/netlink/af_netlink.c:1914
sock_sendmsg_nosec net/socket.c:725 [inline]
sock_sendmsg+0xd9/0x180 net/socket.c:748
____sys_sendmsg+0x6ac/0x940 net/socket.c:2494
___sys_sendmsg+0x135/0x1d0 net/socket.c:2548
__sys_sendmsg+0x117/0x1e0 net/socket.c:2577
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

RIP: 0033:0x7f7723e7cae9

Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007f7724c950c8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f7723f9bf80 RCX: 00007f7723e7cae9

RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003

RBP: 00007f7723ec847a R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 000000000000004d R14: 00007f7723f9bf80 R15: 00007ffec7033f18
</TASK>


Tested on:

commit: 048c796b ipv6: adjust ndisc_is_useropt() to also retur..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git

console output: https://syzkaller.appspot.com/x/log.txt?x=11b78d73a80000

kernel config: https://syzkaller.appspot.com/x/.config?x=fa5bd4cd5ab6259d
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4f06495414e92701d5
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=17752973a80000

[Hillf Danton]

On Fri, 11 Aug 2023 06:57:06 -0700

> HEAD commit: 048c796beb6e ipv6: adjust ndisc_is_useropt() to also retur..
> git tree: net

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158dfa43a80000

Try to revert 718cb09aaa6f

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git 048c796beb6e

--- x/net/8021q/vlan.c
+++ y/net/8021q/vlan.c

@@ -384,7 +384,7 @@ static int vlan_device_event(struct noti

dev->name);
vlan_vid_add(dev, htons(ETH_P_8021Q), 0);
}
- if (event == NETDEV_DOWN)

+ if (event == NETDEV_DOWN && (dev->features & NETIF_F_HW_VLAN_CTAG_FILTER))

vlan_vid_del(dev, htons(ETH_P_8021Q), 0);

vlan_info = rtnl_dereference(dev->vlan_info);

--

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+4b4f06...@syzkaller.appspotmail.com

Tested on:

commit: 048c796b ipv6: adjust ndisc_is_useropt() to also retur..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git

console output: https://syzkaller.appspot.com/x/log.txt?x=15158c3da80000

kernel config: https://syzkaller.appspot.com/x/.config?x=fa5bd4cd5ab6259d
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4f06495414e92701d5
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=109521c3a80000

Note: testing is done by a robot and is best-effort only.

[Hillf Danton]

On Fri, 11 Aug 2023 06:57:06 -0700

> HEAD commit: 048c796beb6e ipv6: adjust ndisc_is_useropt() to also retur..
> git tree: net

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=158dfa43a80000

Try to revert 718cb09aaa6f

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git 048c796beb6e

--- x/net/8021q/vlan.c
+++ y/net/8021q/vlan.c
@@ -384,7 +384,7 @@ static int vlan_device_event(struct noti
dev->name);
vlan_vid_add(dev, htons(ETH_P_8021Q), 0);
}
- if (event == NETDEV_DOWN)
+ if (event == NETDEV_DOWN && (dev->features & NETIF_F_HW_VLAN_CTAG_FILTER))
vlan_vid_del(dev, htons(ETH_P_8021Q), 0);

vlan_info = rtnl_dereference(dev->vlan_info);

@@ -486,6 +486,7 @@ static int vlan_device_event(struct noti
break;
}
unregister_netdevice_many(&list);
+ vlan_vid_del(dev, htons(ETH_P_8021Q), 0);
break;

case NETDEV_PRE_TYPE_CHANGE:
--

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+4b4f06...@syzkaller.appspotmail.com

Tested on:

commit: 048c796b ipv6: adjust ndisc_is_useropt() to also retur..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git

console output: https://syzkaller.appspot.com/x/log.txt?x=107419c3a80000

kernel config: https://syzkaller.appspot.com/x/.config?x=fa5bd4cd5ab6259d
dashboard link: https://syzkaller.appspot.com/bug?extid=4b4f06495414e92701d5
compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=15d7ea27a80000