syzbot
general protection fault in bpf_redirect
Status: closed as invalid on 2026/09/11 15:35
Subsystems:
bpf
net
Labels:
prio:low
[Documentation on labels]
First crash: 114d, last: 100d
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Last patch testing requests (2)
Sample crash report:
syzkaller0: entered promiscuous mode
syzkaller0: entered allmulticast mode
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000007: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f]
CPU: 0 UID: 0 PID: 5922 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:bpf_net_ctx_get_ri include/linux/filter.h:819 [inline]
RIP: 0010:____bpf_redirect net/core/filter.c:2555 [inline]
RIP: 0010:bpf_redirect+0x5d/0x180 net/core/filter.c:2553
Code: 48 c1 ea 03 80 3c 02 00 0f 85 1c 01 00 00 48 8b 9b d8 18 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 73 38 4c 89 f2 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e cf 00 00 00 44 8b 6b 38 31 ff
RSP: 0018:ffffc900045473a8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff920006e1609
RDX: 0000000000000007 RSI: ffffffff896e7827 RDI: ffff88802a2d98d8
RBP: 00000080ffffffff R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888025f9b841 R12: ffff888025f9b7c0
R13: ffffc9000370b000 R14: 0000000000000038 R15: ffff88803634f6c0
FS: 000055557cc56500(0000) GS:ffff8880d6383000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002280 CR3: 00000000269e2000 CR4: 0000000000352ef0
Call Trace:
<TASK>
bpf_prog_6338e008a91e2d10+0x23/0x29
bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline]
__bpf_prog_run include/linux/filter.h:722 [inline]
bpf_prog_run include/linux/filter.h:729 [inline]
bpf_prog_run_data_pointers include/linux/filter.h:917 [inline]
cls_bpf_classify+0x533/0x1320 net/sched/cls_bpf.c:103
tc_classify include/net/tc_wrapper.h:198 [inline]
__tcf_classify net/sched/cls_api.c:1764 [inline]
tcf_classify+0x7ef/0x1250 net/sched/cls_api.c:1860
drr_classify net/sched/sch_drr.c:317 [inline]
drr_enqueue+0x2f4/0xaa0 net/sched/sch_drr.c:346
dev_qdisc_enqueue net/core/dev.c:4174 [inline]
__dev_xmit_skb net/core/dev.c:4289 [inline]
__dev_queue_xmit+0x2fe3/0x4950 net/core/dev.c:4831
dev_queue_xmit include/linux/netdevice.h:3418 [inline]
packet_xmit+0x243/0x310 net/packet/af_packet.c:276
packet_snd net/packet/af_packet.c:3082 [inline]
packet_sendmsg+0x319a/0x5100 net/packet/af_packet.c:3114
sock_sendmsg_nosec net/socket.c:787 [inline]
__sock_sendmsg net/socket.c:802 [inline]
____sys_sendmsg+0x9e1/0xb70 net/socket.c:2698
___sys_sendmsg+0x190/0x1e0 net/socket.c:2752
__sys_sendmsg+0x170/0x220 net/socket.c:2784
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f52a459ce59
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:00007ffdddfe5ca8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f52a4815fa0 RCX: 00007f52a459ce59
RDX: 0000000000000005 RSI: 0000200000000280 RDI: 0000000000000007
RBP: 00007f52a4632d6f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f52a4815fac R14: 00007f52a4815fa0 R15: 00007f52a4815fa0
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bpf_net_ctx_get_ri include/linux/filter.h:819 [inline]
RIP: 0010:____bpf_redirect net/core/filter.c:2555 [inline]
RIP: 0010:bpf_redirect+0x5d/0x180 net/core/filter.c:2553
Code: 48 c1 ea 03 80 3c 02 00 0f 85 1c 01 00 00 48 8b 9b d8 18 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8d 73 38 4c 89 f2 48 c1 ea 03 <0f> b6 04 02 84 c0 74 08 3c 03 0f 8e cf 00 00 00 44 8b 6b 38 31 ff
RSP: 0018:ffffc900045473a8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff920006e1609
RDX: 0000000000000007 RSI: ffffffff896e7827 RDI: ffff88802a2d98d8
RBP: 00000080ffffffff R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: ffff888025f9b841 R12: ffff888025f9b7c0
R13: ffffc9000370b000 R14: 0000000000000038 R15: ffff88803634f6c0
FS: 000055557cc56500(0000) GS:ffff8880d6383000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000002280 CR3: 00000000269e2000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess):
0: 48 c1 ea 03 shr $0x3,%rdx
4: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1)
8: 0f 85 1c 01 00 00 jne 0x12a
e: 48 8b 9b d8 18 00 00 mov 0x18d8(%rbx),%rbx
15: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax
1c: fc ff df
1f: 4c 8d 73 38 lea 0x38(%rbx),%r14
23: 4c 89 f2 mov %r14,%rdx
26: 48 c1 ea 03 shr $0x3,%rdx
* 2a: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction
2e: 84 c0 test %al,%al
30: 74 08 je 0x3a
32: 3c 03 cmp $0x3,%al
34: 0f 8e cf 00 00 00 jle 0x109
3a: 44 8b 6b 38 mov 0x38(%rbx),%r13d
3e: 31 ff xor %edi,%edi
* Struck through repros no longer work on HEAD.