Subject: Re: WARNING in tracepoint_add_func

From: syzbot <[email-masked]>
Date: Thu, 10 Sep 2020 02:44:16 -0700

syzbot has found a reproducer for the following issue on:

HEAD commit:    746f534a tools/libbpf: Avoid counting local symbols in ABI..
git tree:       bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=1317f559900000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a0437fdd630bee11
dashboard link: https://syzkaller.appspot.com/bug?extid=721aa903751db87aa244
compiler:       gcc (GCC) 10.1.0-syz 20200507
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=128ff37d900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

------------[ cut here ]------------
WARNING: CPU: 1 PID: 7451 at kernel/tracepoint.c:243 tracepoint_add_func+0x254/0x880 kernel/tracepoint.c:243
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 7451 Comm: syz-executor.0 Not tainted 5.9.0-rc1-syzkaller #0
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+0x18f/0x20d lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:231
 __warn.cold+0x20/0x4a kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:tracepoint_add_func+0x254/0x880 kernel/tracepoint.c:243
Code: 44 24 20 48 8b 5b 08 80 38 00 0f 85 6b 05 00 00 48 8b 44 24 08 48 3b 58 08 0f 85 2d ff ff ff 41 bc ef ff ff ff e8 7c 68 fe ff <0f> 0b e8 75 68 fe ff 44 89 e0 48 83 c4 38 5b 5d 41 5c 41 5d 41 5e
RSP: 0018:ffffc900056e7ac0 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffc90000e76000 RCX: ffffffff8175d632
RDX: ffff8880a85ae5c0 RSI: ffffffff8175d694 RDI: ffff8880942a1798
RBP: ffffffff82101830 R08: 0000000000000000 R09: ffffffff89c13687
R10: 000000000000000a R11: 0000000000000000 R12: 00000000ffffffef
R13: 0000000000000000 R14: dffffc0000000000 R15: ffff8880942a1790
 tracepoint_probe_register_prio kernel/tracepoint.c:315 [inline]
 tracepoint_probe_register+0x9c/0xe0 kernel/tracepoint.c:335
 __bpf_probe_register kernel/trace/bpf_trace.c:1950 [inline]
 bpf_probe_register+0x16c/0x1d0 kernel/trace/bpf_trace.c:1955
 bpf_raw_tracepoint_open+0x34e/0xb20 kernel/bpf/syscall.c:2741
 __do_sys_bpf+0x1336/0x4c20 kernel/bpf/syscall.c:4220
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5b9
Code: 5d b4 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f23d5b85c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 0000000000001800 RCX: 000000000045d5b9
RDX: 0000000000000010 RSI: 0000000020000080 RDI: 0000000000000011
RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007fffab077bbf R14: 00007f23d5b869c0 R15: 000000000118cf4c
Kernel Offset: disabled
Rebooting in 86400 seconds..