[syzbot] [net?] WARNING in rcu_note_context_switch (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9448598b22c5 Linux 6.19-rc2
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11423b1a580000
kernel config: https://syzkaller.appspot.com/x/.config?x=a11e0f726bfb6765
dashboard link: https://syzkaller.appspot.com/bug?extid=84d4a405ed798b40c96d
compiler: gcc (Debian 12.2.0-14+deb12u1) 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 (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-9448598b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e6328e25c1c8/vmlinux-9448598b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d1590b31d26d/bzImage-9448598b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+84d4a4...@syzkaller.appspotmail.com

------------[ cut here ]------------
Voluntary context switch within RCU read-side critical section!
WARNING: kernel/rcu/tree_plugin.h:332 at rcu_note_context_switch+0x104/0x1de0 kernel/rcu/tree_plugin.h:332, CPU#0: syz.2.13843/20505
Modules linked in:
CPU: 0 UID: 0 PID: 20505 Comm: syz.2.13843 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:rcu_note_context_switch+0x104/0x1de0 kernel/rcu/tree_plugin.h:332
Code: 0f b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 08 84 d2 0f 85 bb 10 00 00 8b 85 84 04 00 00 85 c0 7e 0c 48 8d 3d 9c 94 e7 0e <67> 48 0f b9 3a 65 48 8b 2d 57 0e 0e 12 48 8d bd 84 04 00 00 48 b8
RSP: 0018:ffffc9000410f028 EFLAGS: 00010002
RAX: 0000000000000001 RBX: ffff88806a43bc40 RCX: ffffffff81a41b2f
RDX: 0000000000000000 RSI: ffffffff8bf2b380 RDI: ffffffff908c3650
RBP: ffff888054ce24c0 R08: 0000000000000000 R09: fffffbfff211169a
R10: ffffffff9088b4d7 R11: ffff888054ce2ff0 R12: 0000000000000000
R13: ffff888054ce24c0 R14: ffffffff9088e574 R15: ffff88806a43ac80
FS: 00007f883fff66c0(0000) GS:ffff8880d68f5000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 000000004a53a000 CR4: 0000000000352ef0
Call Trace:
<TASK>
__schedule+0x2dc/0x6150 kernel/sched/core.c:6748
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6960
netlink_broadcast_filtered+0x96d/0xf90 net/netlink/af_netlink.c:1547
nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
nlmsg_multicast include/net/netlink.h:1184 [inline]
nlmsg_notify+0x9e/0x220 net/netlink/af_netlink.c:2593
__ip6_del_rt_siblings net/ipv6/route.c:4056 [inline]
ip6_route_del+0x115c/0x1d70 net/ipv6/route.c:4196
inet6_rtm_delroute+0x27c/0x3b0 net/ipv6/route.c:5629
rtnetlink_rcv_msg+0x95e/0xe90 net/core/rtnetlink.c:6958
netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550
netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592
___sys_sendmsg+0x134/0x1d0 net/socket.c:2646
__sys_sendmsg+0x16d/0x220 net/socket.c:2678
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f8841d8f7c9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f883fff6038 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f8841fe5fa0 RCX: 00007f8841d8f7c9
RDX: 0000000000000000 RSI: 0000200000000280 RDI: 0000000000000003
RBP: 00007f8841e13f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8841fe6038 R14: 00007f8841fe5fa0 R15: 00007fffea27ccb8
</TASK>
----------------
Code disassembly (best guess):
0: 0f b6 14 02 movzbl (%rdx,%rax,1),%edx
4: 48 89 f8 mov %rdi,%rax
7: 83 e0 07 and $0x7,%eax
a: 83 c0 03 add $0x3,%eax
d: 38 d0 cmp %dl,%al
f: 7c 08 jl 0x19
11: 84 d2 test %dl,%dl
13: 0f 85 bb 10 00 00 jne 0x10d4
19: 8b 85 84 04 00 00 mov 0x484(%rbp),%eax
1f: 85 c0 test %eax,%eax
21: 7e 0c jle 0x2f
23: 48 8d 3d 9c 94 e7 0e lea 0xee7949c(%rip),%rdi # 0xee794c6
* 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2f: 65 48 8b 2d 57 0e 0e mov %gs:0x120e0e57(%rip),%rbp # 0x120e0e8e
36: 12
37: 48 8d bd 84 04 00 00 lea 0x484(%rbp),%rdi
3e: 48 rex.W
3f: b8 .byte 0xb8


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