WARNING in batadv_is_on_batman_iface

WARNING in batadv_is_on_batman_iface

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    d8924c0d76aa Merge tag 'devprop-4.21-rc1' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=122a373f400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=91a256823ef17263
dashboard link: https://syzkaller.appspot.com/bug?extid=c764de0fcfadca9a8595
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16fd1d67400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c764de0fcfadca9a8595@syzkaller.appspotmail.com

8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
------------[ cut here ]------------
Cannot find parent device
WARNING: CPU: 1 PID: 9391 at net/batman-adv/hard-interface.c:182  
batadv_is_on_batman_iface+0x3ef/0x460 net/batman-adv/hard-interface.c:182
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 9391 Comm: syz-executor2 Not tainted 4.20.0+ #388
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x1d3/0x2c6 lib/dump_stack.c:113
  panic+0x2ad/0x55c kernel/panic.c:188
  __warn.cold.8+0x20/0x45 kernel/panic.c:540
  report_bug+0x254/0x2d0 lib/bug.c:186
  fixup_bug arch/x86/kernel/traps.c:178 [inline]
  do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
  do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:batadv_is_on_batman_iface+0x3ef/0x460  
net/batman-adv/hard-interface.c:182
Code: 8b 45 d0 48 89 45 c0 e9 f5 fe ff ff 4c 89 ff e8 67 f7 03 fa e9 f4 fc  
ff ff e8 2d ec c0 f9 48 c7 c7 00 16 d6 88 e8 b1 9f 8a f9 <0f> 0b eb b7 e8  
68 f7 03 fa e9 3e fc ff ff 48 8b 7d c0 e8 5a f7 03
RSP: 0018:ffff8881d31e68b8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff8881d78d0ec0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8164e075 RDI: 0000000000000006
RBP: ffff8881d31e6900 R08: ffff8881b0d9c040 R09: 0000000000000006
R10: 0000000000000000 R11: ffff8881b0d9c040 R12: 0000000000000000
R13: ffff8881bd630140 R14: 00000000447eea95 R15: ffff8881d78d0fc8
  batadv_is_valid_iface net/batman-adv/hard-interface.c:205 [inline]
  batadv_hardif_add_interface net/batman-adv/hard-interface.c:917 [inline]
  batadv_hard_if_event+0x944/0x11e0 net/batman-adv/hard-interface.c:1041
  notifier_call_chain+0x17e/0x380 kernel/notifier.c:93
  __raw_notifier_call_chain kernel/notifier.c:394 [inline]
  raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
  call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1733
  call_netdevice_notifiers net/core/dev.c:1751 [inline]
  register_netdevice+0xb98/0x10f0 net/core/dev.c:8570
  ip6gre_newlink_common.isra.29+0x165/0x3c0 net/ipv6/ip6_gre.c:1948
  ip6gre_newlink+0x353/0x9b0 net/ipv6/ip6_gre.c:1981
  rtnl_newlink+0xf08/0x1da0 net/core/rtnetlink.c:3175
  rtnetlink_rcv_msg+0x46a/0xc20 net/core/rtnetlink.c:4950
  netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477
  rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4968
  netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
  netlink_unicast+0x5a5/0x760 net/netlink/af_netlink.c:1336
  netlink_sendmsg+0xa18/0xfc0 net/netlink/af_netlink.c:1917
  sock_sendmsg_nosec net/socket.c:621 [inline]
  sock_sendmsg+0xd5/0x120 net/socket.c:631
  ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
  __sys_sendmsg+0x11d/0x280 net/socket.c:2154
  __do_sys_sendmsg net/socket.c:2163 [inline]
  __se_sys_sendmsg net/socket.c:2161 [inline]
  __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457759
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fd848638c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457759
RDX: 0000000000000000 RSI: 00000000200005c0 RDI: 0000000000000003
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd8486396d4
R13: 00000000004c49f1 R14: 00000000004d80d0 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug 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 bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with  
syzbot.
syzbot can test patches for this bug, for details see:
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[B.A.T.M.A.N.] WARNING in batadv_is_on_batman_iface

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    d8924c0d76aa Merge tag 'devprop-4.21-rc1' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=122a373f400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=91a256823ef17263
dashboard link: https://syzkaller.appspot.com/bug?extid=c764de0fcfadca9a8595
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16fd1d67400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c764de0fcfadca9a8595@syzkaller.appspotmail.com

8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
8021q: adding VLAN 0 to HW filter on device team0
------------[ cut here ]------------
Cannot find parent device
WARNING: CPU: 1 PID: 9391 at net/batman-adv/hard-interface.c:182  
batadv_is_on_batman_iface+0x3ef/0x460 net/batman-adv/hard-interface.c:182
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 9391 Comm: syz-executor2 Not tainted 4.20.0+ #388
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
  __dump_stack lib/dump_stack.c:77 [inline]
  dump_stack+0x1d3/0x2c6 lib/dump_stack.c:113
  panic+0x2ad/0x55c kernel/panic.c:188
  __warn.cold.8+0x20/0x45 kernel/panic.c:540
  report_bug+0x254/0x2d0 lib/bug.c:186
  fixup_bug arch/x86/kernel/traps.c:178 [inline]
  do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
  do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
  invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:973
RIP: 0010:batadv_is_on_batman_iface+0x3ef/0x460  
net/batman-adv/hard-interface.c:182
Code: 8b 45 d0 48 89 45 c0 e9 f5 fe ff ff 4c 89 ff e8 67 f7 03 fa e9 f4 fc  
ff ff e8 2d ec c0 f9 48 c7 c7 00 16 d6 88 e8 b1 9f 8a f9 <0f> 0b eb b7 e8  
68 f7 03 fa e9 3e fc ff ff 48 8b 7d c0 e8 5a f7 03
RSP: 0018:ffff8881d31e68b8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: ffff8881d78d0ec0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff8164e075 RDI: 0000000000000006
RBP: ffff8881d31e6900 R08: ffff8881b0d9c040 R09: 0000000000000006
R10: 0000000000000000 R11: ffff8881b0d9c040 R12: 0000000000000000
R13: ffff8881bd630140 R14: 00000000447eea95 R15: ffff8881d78d0fc8
  batadv_is_valid_iface net/batman-adv/hard-interface.c:205 [inline]
  batadv_hardif_add_interface net/batman-adv/hard-interface.c:917 [inline]
  batadv_hard_if_event+0x944/0x11e0 net/batman-adv/hard-interface.c:1041
  notifier_call_chain+0x17e/0x380 kernel/notifier.c:93
  __raw_notifier_call_chain kernel/notifier.c:394 [inline]
  raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
  call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1733
  call_netdevice_notifiers net/core/dev.c:1751 [inline]
  register_netdevice+0xb98/0x10f0 net/core/dev.c:8570
  ip6gre_newlink_common.isra.29+0x165/0x3c0 net/ipv6/ip6_gre.c:1948
  ip6gre_newlink+0x353/0x9b0 net/ipv6/ip6_gre.c:1981
  rtnl_newlink+0xf08/0x1da0 net/core/rtnetlink.c:3175
  rtnetlink_rcv_msg+0x46a/0xc20 net/core/rtnetlink.c:4950
  netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477
  rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4968
  netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
  netlink_unicast+0x5a5/0x760 net/netlink/af_netlink.c:1336
  netlink_sendmsg+0xa18/0xfc0 net/netlink/af_netlink.c:1917
  sock_sendmsg_nosec net/socket.c:621 [inline]
  sock_sendmsg+0xd5/0x120 net/socket.c:631
  ___sys_sendmsg+0x7fd/0x930 net/socket.c:2116
  __sys_sendmsg+0x11d/0x280 net/socket.c:2154
  __do_sys_sendmsg net/socket.c:2163 [inline]
  __se_sys_sendmsg net/socket.c:2161 [inline]
  __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2161
  do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
  entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457759
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fd848638c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457759
RDX: 0000000000000000 RSI: 00000000200005c0 RDI: 0000000000000003
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fd8486396d4
R13: 00000000004c49f1 R14: 00000000004d80d0 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..


---
This bug 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 bug report. See:
https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with  
syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches

Re: WARNING in batadv_is_on_batman_iface

[Sven Eckelmann]

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On Sunday, 30 December 2018 11.41.03 CET syzbot wrote:
[...]
> HEAD commit:    d8924c0d76aa Merge tag 'devprop-4.21-rc1' of git://git.ker..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=122a373f400000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=91a256823ef17263
> dashboard link: https://syzkaller.appspot.com/bug?extid=c764de0fcfadca9a8595
> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16fd1d67400000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+c764de0fcfadca9a8595@syzkaller.appspotmail.com

What is the bug here? The kernel module showed a warning because the parent 
device cannot be found in the same netns using __dev_get_by_index.

The test system was just configured to panic on warnings. So are we now 
expected to show warnings or what is the expected behavior?

This behavior was added with commit b7eddd0b3950 ("batman-adv: prevent using 
any virtual device created on batman-adv as hard-interface") - 3d48811b27f5 in 
the out-of-tree module.

Kind regards,
	Sven

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b7eddd0b3950ea9dc863f1cbfa30d172dbf772f4

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Re: WARNING in batadv_is_on_batman_iface

[Sven Eckelmann]

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On Sunday, 30 December 2018 11.41.03 CET syzbot wrote:
[...]
> HEAD commit:    d8924c0d76aa Merge tag 'devprop-4.21-rc1' of git://git.ker..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=122a373f400000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=91a256823ef17263
> dashboard link: https://syzkaller.appspot.com/bug?extid=c764de0fcfadca9a8595
> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16fd1d67400000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+c764de0fcfadca9a8595-Pl5Pbv+GP7P466ipTTIvnc23WoclnBCfAL8bYrjMMd8@public.gmane.org

What is the bug here? The kernel module showed a warning because the parent 
device cannot be found in the same netns using __dev_get_by_index.

The test system was just configured to panic on warnings. So are we now 
expected to show warnings or what is the expected behavior?

This behavior was added with commit b7eddd0b3950 ("batman-adv: prevent using 
any virtual device created on batman-adv as hard-interface") - 3d48811b27f5 in 
the out-of-tree module.

Kind regards,
	Sven

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b7eddd0b3950ea9dc863f1cbfa30d172dbf772f4

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Re: [B.A.T.M.A.N.] WARNING in batadv_is_on_batman_iface

[Sven Eckelmann]

[-- Attachment #1: Type: text/plain, Size: 1288 bytes --]

On Sunday, 30 December 2018 11.41.03 CET syzbot wrote:
[...]
> HEAD commit:    d8924c0d76aa Merge tag 'devprop-4.21-rc1' of git://git.ker..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=122a373f400000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=91a256823ef17263
> dashboard link: https://syzkaller.appspot.com/bug?extid=c764de0fcfadca9a8595
> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16fd1d67400000
> 
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: syzbot+c764de0fcfadca9a8595@syzkaller.appspotmail.com

What is the bug here? The kernel module showed a warning because the parent 
device cannot be found in the same netns using __dev_get_by_index.

The test system was just configured to panic on warnings. So are we now 
expected to show warnings or what is the expected behavior?

This behavior was added with commit b7eddd0b3950 ("batman-adv: prevent using 
any virtual device created on batman-adv as hard-interface") - 3d48811b27f5 in 
the out-of-tree module.

Kind regards,
	Sven

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b7eddd0b3950ea9dc863f1cbfa30d172dbf772f4

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Re: WARNING in batadv_is_on_batman_iface

[Dmitry Vyukov]

On Sun, Dec 30, 2018 at 12:00 PM Sven Eckelmann <sven@narfation.org> wrote:
>
> On Sunday, 30 December 2018 11.41.03 CET syzbot wrote:
> [...]
> > HEAD commit:    d8924c0d76aa Merge tag 'devprop-4.21-rc1' of git://git.ker..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=122a373f400000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=91a256823ef17263
> > dashboard link: https://syzkaller.appspot.com/bug?extid=c764de0fcfadca9a8595
> > compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16fd1d67400000
> >
> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+c764de0fcfadca9a8595@syzkaller.appspotmail.com
>
> What is the bug here? The kernel module showed a warning because the parent
> device cannot be found in the same netns using __dev_get_by_index.
>
> The test system was just configured to panic on warnings. So are we now
> expected to show warnings or what is the expected behavior?
>
> This behavior was added with commit b7eddd0b3950 ("batman-adv: prevent using
> any virtual device created on batman-adv as hard-interface") - 3d48811b27f5 in
> the out-of-tree module.

Hi Sven,

The problem is that kernel code uses WARNING when it should not.
For WARN guidelines please see this:
https://elixir.bootlin.com/linux/v4.20/source/include/asm-generic/bug.h#L81
and this (search for WARN_ON_ONCE):
https://lwn.net/Articles/769365/


> Kind regards,
>         Sven
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b7eddd0b3950ea9dc863f1cbfa30d172dbf772f4

Re: WARNING in batadv_is_on_batman_iface

[Dmitry Vyukov via B.A.T.M.A.N]

[-- Attachment #1: Type: text/plain, Size: 245 bytes --]

The sender domain has a DMARC Reject/Quarantine policy which disallows
sending mailing list messages using the original "From" header.

To mitigate this problem, the original message has been wrapped
automatically by the mailing list software.

[-- Attachment #2: Type: message/rfc822, Size: 5429 bytes --]

From: Dmitry Vyukov <dvyukov-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
To: Sven Eckelmann <sven-KaDOiPu9UxWEi8DpZVb4nw@public.gmane.org>
Cc: syzbot <syzbot+c764de0fcfadca9a8595-Pl5Pbv+GP7P466ipTTIvnc23WoclnBCfAL8bYrjMMd8@public.gmane.org>, a@unstable.cc, b.a.t.m.a.n-ZwoEplunGu2X36UT3dwllkB+6BGkLq7r@public.gmane.org, David Miller <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org>, LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, mareklindner-rVWd3aGhH2z5bpWLKbzFeg@public.gmane.org, netdev <netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, sw-2YrNx6rUIHYiY0qSoAWiAoQuADTiUCJX@public.gmane.org, syzkaller-bugs <syzkaller-bugs-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>
Subject: Re: WARNING in batadv_is_on_batman_iface
Date: Sun, 30 Dec 2018 12:08:53 +0100
Message-ID: <CACT4Y+Yb+OvJ8c4Vot9pcTEF1OhTHeu=XK5Jb=EXEBv6xmNwnQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>

On Sun, Dec 30, 2018 at 12:00 PM Sven Eckelmann <sven-KaDOiPu9UxWEi8DpZVb4nw@public.gmane.org> wrote:
>
> On Sunday, 30 December 2018 11.41.03 CET syzbot wrote:
> [...]
> > HEAD commit:    d8924c0d76aa Merge tag 'devprop-4.21-rc1' of git://git.ker..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=122a373f400000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=91a256823ef17263
> > dashboard link: https://syzkaller.appspot.com/bug?extid=c764de0fcfadca9a8595
> > compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16fd1d67400000
> >
> > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > Reported-by: syzbot+c764de0fcfadca9a8595-Pl5Pbv+GP7P466ipTTIvnc23WoclnBCfAL8bYrjMMd8@public.gmane.org
>
> What is the bug here? The kernel module showed a warning because the parent
> device cannot be found in the same netns using __dev_get_by_index.
>
> The test system was just configured to panic on warnings. So are we now
> expected to show warnings or what is the expected behavior?
>
> This behavior was added with commit b7eddd0b3950 ("batman-adv: prevent using
> any virtual device created on batman-adv as hard-interface") - 3d48811b27f5 in
> the out-of-tree module.

Hi Sven,

The problem is that kernel code uses WARNING when it should not.
For WARN guidelines please see this:
https://elixir.bootlin.com/linux/v4.20/source/include/asm-generic/bug.h#L81
and this (search for WARN_ON_ONCE):
https://lwn.net/Articles/769365/


> Kind regards,
>         Sven
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b7eddd0b3950ea9dc863f1cbfa30d172dbf772f4