overlayfs: cannot append lower layer Oops: general protection fault, probably for non-canonical address 0xdffffc000000000e: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000070-0x0000000000000077] CPU: 3 UID: 0 PID: 13663 Comm: syz.5.2467 Not tainted 6.14.0-rc6-syzkaller-00003-g4d872d51bc9d #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:skb_segment+0x193b/0x40b0 net/core/skbuff.c:4712 Code: 00 00 fe e9 54 eb ff ff e8 b2 37 8b f8 48 8b 84 24 d0 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 09 3c 03 7f 05 e8 a4 55 ee f8 48 8b 84 24 d0 RSP: 0018:ffffc90003c2e7f8 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000020048 RCX: ffffffff892ea8db RDX: 000000000000000e RSI: ffffffff892eb92e RDI: 0000000000000070 RBP: ffffc90003c2e9a0 R08: 0000000000000005 R09: 000000000000ffff R10: 000000000000ffff R11: aaaa0aaaaaaaaaaa R12: ffff88805ba31840 R13: 000000000001fffe R14: 000000000001fffe R15: 000000000000ffff FS: 00007f08e6f4d6c0(0000) GS:ffff88806a900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000400000200000 CR3: 00000000508ba000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tcp_gso_segment+0x3ca/0x1940 net/ipv4/tcp_offload.c:179 tcp6_gso_segment net/ipv6/tcpv6_offload.c:184 [inline] tcp6_gso_segment+0x207/0x1570 net/ipv6/tcpv6_offload.c:151 ipv6_gso_segment+0x80b/0x1d90 net/ipv6/ip6_offload.c:152 skb_mac_gso_segment+0x2a6/0x650 net/core/gso.c:53 __skb_gso_segment+0x36e/0x700 net/core/gso.c:124 skb_gso_segment include/net/gso.h:83 [inline] validate_xmit_skb+0x669/0xf90 net/core/dev.c:3887 validate_xmit_skb_list+0xc1/0x130 net/core/dev.c:3937 sch_direct_xmit+0x398/0xc30 net/sched/sch_generic.c:328 qdisc_restart net/sched/sch_generic.c:408 [inline] __qdisc_run+0x53f/0x1a10 net/sched/sch_generic.c:416 __dev_xmit_skb net/core/dev.c:4108 [inline] __dev_queue_xmit+0x2aa4/0x43e0 net/core/dev.c:4615 dev_queue_xmit include/linux/netdevice.h:3313 [inline] neigh_hh_output include/net/neighbour.h:523 [inline] neigh_output include/net/neighbour.h:537 [inline] ip6_finish_output2+0xed9/0x20a0 net/ipv6/ip6_output.c:141 __ip6_finish_output net/ipv6/ip6_output.c:215 [inline] ip6_finish_output+0x3f9/0x1360 net/ipv6/ip6_output.c:226 NF_HOOK_COND include/linux/netfilter.h:303 [inline] ip6_output+0x1f8/0x540 net/ipv6/ip6_output.c:247 dst_output include/net/dst.h:459 [inline] NF_HOOK include/linux/netfilter.h:314 [inline] NF_HOOK include/linux/netfilter.h:308 [inline] ip6_xmit+0x12d2/0x2300 net/ipv6/ip6_output.c:366 inet6_csk_xmit+0x3ce/0x740 net/ipv6/inet6_connection_sock.c:135 __tcp_transmit_skb+0x1b02/0x3ec0 net/ipv4/tcp_output.c:1471 tcp_transmit_skb net/ipv4/tcp_output.c:1489 [inline] tcp_write_xmit+0x12b1/0x8560 net/ipv4/tcp_output.c:2832 __tcp_push_pending_frames+0xaf/0x390 net/ipv4/tcp_output.c:3015 tcp_push_pending_frames include/net/tcp.h:2124 [inline] tcp_data_snd_check net/ipv4/tcp_input.c:5753 [inline] tcp_rcv_established+0x868/0x2140 net/ipv4/tcp_input.c:6290 tcp_v6_do_rcv+0x897/0x1740 net/ipv6/tcp_ipv6.c:1644 sk_backlog_rcv include/net/sock.h:1122 [inline] __release_sock+0x14c/0x400 net/core/sock.c:3123 __sk_flush_backlog+0x27/0xc0 net/core/sock.c:3143 sk_flush_backlog include/net/sock.h:1185 [inline] tcp_sendmsg_locked+0x2f6e/0x37c0 net/ipv4/tcp.c:1164 tcp_sendmsg+0x2e/0x50 net/ipv4/tcp.c:1358 inet6_sendmsg+0xb9/0x140 net/ipv6/af_inet6.c:659 sock_sendmsg_nosec net/socket.c:718 [inline] __sock_sendmsg net/socket.c:733 [inline] __sys_sendto+0x374/0x4f0 net/socket.c:2187 __do_sys_sendto net/socket.c:2194 [inline] __se_sys_sendto net/socket.c:2190 [inline] __x64_sys_sendto+0xe0/0x1c0 net/socket.c:2190 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f08e618d169 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:00007f08e6f4d038 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f08e63a5fa0 RCX: 00007f08e618d169 RDX: ffffffffffffff1d RSI: 00004000000000c0 RDI: 0000000000000006 RBP: 00007f08e620e2a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000850 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f08e63a5fa0 R15: 00007fff7dbcb888 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:skb_segment+0x193b/0x40b0 net/core/skbuff.c:4712 Code: 00 00 fe e9 54 eb ff ff e8 b2 37 8b f8 48 8b 84 24 d0 00 00 00 48 8d 78 70 48 b8 00 00 00 00 00 fc ff df 48 89 fa 48 c1 ea 03 <0f> b6 04 02 84 c0 74 09 3c 03 7f 05 e8 a4 55 ee f8 48 8b 84 24 d0 RSP: 0018:ffffc90003c2e7f8 EFLAGS: 00010202 RAX: dffffc0000000000 RBX: 0000000000020048 RCX: ffffffff892ea8db RDX: 000000000000000e RSI: ffffffff892eb92e RDI: 0000000000000070 RBP: ffffc90003c2e9a0 R08: 0000000000000005 R09: 000000000000ffff R10: 000000000000ffff R11: aaaa0aaaaaaaaaaa R12: ffff88805ba31840 R13: 000000000001fffe R14: 000000000001fffe R15: 000000000000ffff FS: 00007f08e6f4d6c0(0000) GS:ffff88806a900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000400000200000 CR3: 00000000508ba000 CR4: 0000000000352ef0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: 00 fe add %bh,%dh 2: e9 54 eb ff ff jmp 0xffffeb5b 7: e8 b2 37 8b f8 call 0xf88b37be c: 48 8b 84 24 d0 00 00 mov 0xd0(%rsp),%rax 13: 00 14: 48 8d 78 70 lea 0x70(%rax),%rdi 18: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax 1f: fc ff df 22: 48 89 fa mov %rdi,%rdx 25: 48 c1 ea 03 shr $0x3,%rdx * 29: 0f b6 04 02 movzbl (%rdx,%rax,1),%eax <-- trapping instruction 2d: 84 c0 test %al,%al 2f: 74 09 je 0x3a 31: 3c 03 cmp $0x3,%al 33: 7f 05 jg 0x3a 35: e8 a4 55 ee f8 call 0xf8ee55de 3a: 48 rex.W 3b: 8b .byte 0x8b 3c: 84 24 d0 test %ah,(%rax,%rdx,8)