Subject: Re: [syzbot] [bpf?] linux-next boot error: WARNING in register_btf_kfunc_id_set

From: Stephen Rothwell <[email-masked]>
Date: Fri, 2 Feb 2024 09:16:12 +1100

Hi syzbot,

On Thu, 01 Feb 2024 12:44:30 -0800 syzbot <[email-masked]> wrote:
>
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    51b70ff55ed8 Add linux-next specific files for 20240201
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=17b05288180000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=88d85200b6a62126
> dashboard link: https://syzkaller.appspot.com/bug?extid=0e9c9f96dbdc31a8431b
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/f2d3a98d07e5/disk-51b70ff5.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/d525430ddf13/vmlinux-51b70ff5.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/6d1ec0b50066/bzImage-51b70ff5.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: [email-masked]
> 
> greybus: registered new driver hid
> greybus: registered new driver gbphy
> gb_gbphy: registered new driver usb
> asus_wmi: ASUS WMI generic driver loaded
> usbcore: registered new interface driver snd-usb-audio
> usbcore: registered new interface driver snd-ua101
> usbcore: registered new interface driver snd-usb-usx2y
> usbcore: registered new interface driver snd-usb-us122l
> usbcore: registered new interface driver snd-usb-caiaq
> usbcore: registered new interface driver snd-usb-6fire
> usbcore: registered new interface driver snd-usb-hiface
> usbcore: registered new interface driver snd-bcd2000
> usbcore: registered new interface driver snd_usb_pod
> usbcore: registered new interface driver snd_usb_podhd
> usbcore: registered new interface driver snd_usb_toneport
> usbcore: registered new interface driver snd_usb_variax
> drop_monitor: Initializing network drop monitor service
> NET: Registered PF_LLC protocol family
> GACT probability on
> Mirror/redirect action on
> Simple TC action Loaded
> netem: version 1.3
> u32 classifier
>     Performance counters on
>     input device check on
>     Actions configured
> nf_conntrack_irc: failed to register helpers
> nf_conntrack_sane: failed to register helpers
> nf_conntrack_sip: failed to register helpers
> xt_time: kernel timezone is -0000
> IPVS: Registered protocols (TCP, UDP, SCTP, AH, ESP)
> IPVS: Connection hash table configured (size=4096, memory=32Kbytes)
> IPVS: ipvs loaded.
> IPVS: [rr] scheduler registered.
> IPVS: [wrr] scheduler registered.
> IPVS: [lc] scheduler registered.
> IPVS: [wlc] scheduler registered.
> IPVS: [fo] scheduler registered.
> IPVS: [ovf] scheduler registered.
> IPVS: [lblc] scheduler registered.
> IPVS: [lblcr] scheduler registered.
> IPVS: [dh] scheduler registered.
> IPVS: [sh] scheduler registered.
> IPVS: [mh] scheduler registered.
> IPVS: [sed] scheduler registered.
> IPVS: [nq] scheduler registered.
> IPVS: [twos] scheduler registered.
> IPVS: [sip] pe registered.
> ipip: IPv4 and MPLS over IPv4 tunneling driver
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 1 at kernel/bpf/btf.c:8131 register_btf_kfunc_id_set+0x261/0x290 kernel/bpf/btf.c:8131
> Modules linked in:
> CPU: 1 PID: 1 Comm: swapper/0 Not tainted 6.8.0-rc2-next-20240201-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
> RIP: 0010:register_btf_kfunc_id_set+0x261/0x290 kernel/bpf/btf.c:8131
> Code: 16 e8 b3 fb db ff bd 0b 00 00 00 eb 0a e8 a7 fb db ff bd 0d 00 00 00 89 ef 4c 89 f6 5b 41 5e 41 5f 5d eb 45 e8 90 fb db ff 90 <0f> 0b 90 e9 22 fe ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c da fd
> RSP: 0000:ffffc90000067940 EFLAGS: 00010293
> RAX: ffffffff81b7d510 RBX: 0000000000000000 RCX: ffff888016a98000
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> RBP: 0000000000000003 R08: ffffffff81b7d311 R09: 1ffffffff1f0b5bd
> R10: dffffc0000000000 R11: fffffbfff1f0b5be R12: 1ffffffff21e0e1d
> R13: dffffc0000000000 R14: ffffffff8caa77c0 R15: dffffc0000000000
> FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000000000 CR3: 000000000df32000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  fou_init+0x50/0x110 net/ipv4/fou_core.c:1239
>  do_one_initcall+0x238/0x830 init/main.c:1233
>  do_initcall_level+0x157/0x210 init/main.c:1295
>  do_initcalls+0x3f/0x80 init/main.c:1311
>  kernel_init_freeable+0x430/0x5d0 init/main.c:1549
>  kernel_init+0x1d/0x2b0 init/main.c:1439
>  ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
>  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:242
>  </TASK>
> 
> 
> ---
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#syz fix: bpf: btf: Add BTF_KFUNCS_START/END macro pair

This is a new version of a commit in linux-next yesterday.

-- 
Cheers,
Stephen Rothwell