syzbot
general protection fault in btf_type_show
Status:
upstream: reported syz repro on 2026/08/26 20:37
Subsystems:
bpf
Labels:
prio:low
[Documentation on labels]
Reported-by: syzbot+37b56485bbbf90ad8489@syzkaller.appspotmail.com
First crash: 5d04h, last: 5d03h
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Last patch testing requests (2)
Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 2 UID: 0 PID: 5908 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:btf_type_show+0x223/0x2e0 kernel/bpf/btf.c:8232
Code: c1 ea 03 80 3c 02 00 0f 85 90 00 00 00 48 8b 1c dd 40 25 fd 8b 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 77 48 8b 43 28 48 8b 0c 24 48 83 c4 08 4d 89 e9 5b
RSP: 0018:ffffc900034bf868 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000028
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: ffffc900034bf970 R11: 0000000000000001 R12: ffffffff9b96b140
R13: ffffc900034bf8e0 R14: ffff888035e3f600 R15: 0000000000000003
FS: 00005555665e7500(0000) GS:ffff8880d5da2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000000 CR3: 0000000027a0f000 CR4: 0000000000352ef0
Call Trace:
<TASK>
btf_type_seq_show_flags+0xca/0x120 kernel/bpf/btf.c:8250
htab_map_seq_show_elem+0x12e/0x350 kernel/bpf/hashtab.c:1669
map_seq_show+0x13d/0x1e0 kernel/bpf/inode.c:293
traverse.part.0.constprop.0+0x107/0x650 fs/seq_file.c:112
traverse fs/seq_file.c:99 [inline]
seq_read_iter+0x93f/0x1270 fs/seq_file.c:196
seq_read+0x344/0x4d0 fs/seq_file.c:163
vfs_read+0x1e4/0xb40 fs/read_write.c:572
ksys_pread64 fs/read_write.c:764 [inline]
__do_sys_pread64 fs/read_write.c:772 [inline]
__se_sys_pread64 fs/read_write.c:769 [inline]
__x64_sys_pread64+0x1eb/0x250 fs/read_write.c:769
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa99f79e0d9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff8937c6c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000011
RAX: ffffffffffffffda RBX: 00007fa99fa25fa0 RCX: 00007fa99f79e0d9
RDX: 0000000000000083 RSI: 0000200000002240 RDI: 0000000000000007
RBP: 00007fa99f835024 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000e5d6 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa99fa25fac R14: 00007fa99fa25fa0 R15: 00007fa99fa25fa0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:btf_type_show+0x223/0x2e0 kernel/bpf/btf.c:8232
Code: c1 ea 03 80 3c 02 00 0f 85 90 00 00 00 48 8b 1c dd 40 25 fd 8b 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 28 48 89 fa 48 c1 ea 03 <80> 3c 02 00 75 77 48 8b 43 28 48 8b 0c 24 48 83 c4 08 4d 89 e9 5b
RSP: 0018:ffffc900034bf868 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000005 RSI: 0000000000000000 RDI: 0000000000000028
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: ffffc900034bf970 R11: 0000000000000001 R12: ffffffff9b96b140
R13: ffffc900034bf8e0 R14: ffff888035e3f600 R15: 0000000000000003
FS: 00005555665e7500(0000) GS:ffff8880d5da2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000000 CR3: 0000000027a0f000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
0: c1 ea 03 shr $0x3,%edx
3: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
7: 0f 85 90 00 00 00 jne 0x9d
d: 48 8b 1c dd 40 25 fd mov -0x7402dac0(,%rbx,8),%rbx
14: 8b
15: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
1c: fc ff df
1f: 48 8d 7b 28 lea 0x28(%rbx),%rdi
23: 48 89 fa mov %rdi,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) <-- trapping instruction
2e: 75 77 jne 0xa7
30: 48 8b 43 28 mov 0x28(%rbx),%rax
34: 48 8b 0c 24 mov (%rsp),%rcx
38: 48 83 c4 08 add $0x8,%rsp
3c: 4d 89 e9 mov %r13,%r9
3f: 5b pop %rbx
* Struck through repros no longer work on HEAD.