From: syzbot <syzbot+444ca0907e96f7c5e48b@xxxxxxxxxxxxxxxxxxxxxxxxx> Date: Sun, 21 May 2023 22:51:02 -0700 > Hello, > > syzbot found the following issue on: > > HEAD commit: f1fcbaa18b28 Linux 6.4-rc2 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1216efba280000 > kernel config: https://syzkaller.appspot.com/x/.config?x=ac0db1213414a978 > dashboard link: https://syzkaller.appspot.com/bug?extid=444ca0907e96f7c5e48b > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > userspace arch: i386 > > Unfortunately, I don't have any reproducer for this issue yet. > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/ea7e2a44b1f9/disk-f1fcbaa1.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/f4e3201419a9/vmlinux-f1fcbaa1.xz > kernel image: https://storage.googleapis.com/syzbot-assets/c2cd3eb9954b/bzImage-f1fcbaa1.xz > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+444ca0907e96f7c5e48b@xxxxxxxxxxxxxxxxxxxxxxxxx > > general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] > CPU: 0 PID: 6829 Comm: syz-executor.1 Not tainted 6.4.0-rc2-syzkaller #0 The last syz-executor.1 seems to create UDP_LITE (0x88) sk. https://syzkaller.appspot.com/text?tag=CrashLog&x=1216efba280000 ---8<--- 14:25:52 executing program 1: r0 = socket$inet6(0xa, 0x80002, 0x88) bind$inet6(r0, &(0x7f00000001c0)={0xa, 0x10010000004e20}, 0x1c) syz_emit_ethernet(0x83, &(0x7f0000000040)=ANY=[@ANYBLOB="aaaaaaaaaaaaaaaaaaab90aa86dd601bfc97004d8880fe800001000000000000000000000600ff02000000000000000000000000000101004e20004590"], 0x0) ppoll(&(0x7f0000000240)=[{r0}], 0x1, &(0x7f0000000140), 0x0, 0x0) ---8<--- udplitev6_rcv() calls __udp6_lib_rcv(), which expects .sysctl_rmem_offset or sysctl_rmem is configured in sk_prot, but udplitev6_prot has neither. I'll post a fix after testing. Thanks, Kuniyuki > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 > RIP: 0010:sk_get_rmem0 include/net/sock.h:2907 [inline] > RIP: 0010:__sk_mem_raise_allocated+0x806/0x17a0 net/core/sock.c:3006 > Code: c1 ea 03 80 3c 02 00 0f 85 23 0f 00 00 48 8b 44 24 08 48 8b 98 38 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <0f> b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 0f 8d 6f 0a 00 00 8b > RSP: 0018:ffffc90005d7f450 EFLAGS: 00010246 > RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90004d92000 > RDX: 0000000000000000 RSI: ffffffff88066482 RDI: ffffffff8e2ccbb8 > RBP: ffff8880173f7000 R08: 0000000000000005 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000030000 > R13: 0000000000000001 R14: 0000000000000340 R15: 0000000000000001 > FS: 0000000000000000(0000) GS:ffff8880b9800000(0063) knlGS:00000000f7f1cb40 > CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 > CR2: 000000002e82f000 CR3: 0000000034ff0000 CR4: 00000000003506f0 > Call Trace: > <TASK> > __sk_mem_schedule+0x6c/0xe0 net/core/sock.c:3077 > udp_rmem_schedule net/ipv4/udp.c:1539 [inline] > __udp_enqueue_schedule_skb+0x776/0xb30 net/ipv4/udp.c:1581 > __udpv6_queue_rcv_skb net/ipv6/udp.c:666 [inline] > udpv6_queue_rcv_one_skb+0xc39/0x16c0 net/ipv6/udp.c:775 > udpv6_queue_rcv_skb+0x194/0xa10 net/ipv6/udp.c:793 > __udp6_lib_mcast_deliver net/ipv6/udp.c:906 [inline] > __udp6_lib_rcv+0x1bda/0x2bd0 net/ipv6/udp.c:1013 > ip6_protocol_deliver_rcu+0x2e7/0x1250 net/ipv6/ip6_input.c:437 > ip6_input_finish+0x150/0x2f0 net/ipv6/ip6_input.c:482 > NF_HOOK include/linux/netfilter.h:303 [inline] > NF_HOOK include/linux/netfilter.h:297 [inline] > ip6_input+0xa0/0xd0 net/ipv6/ip6_input.c:491 > ip6_mc_input+0x40b/0xf50 net/ipv6/ip6_input.c:585 > dst_input include/net/dst.h:468 [inline] > ip6_rcv_finish net/ipv6/ip6_input.c:79 [inline] > NF_HOOK include/linux/netfilter.h:303 [inline] > NF_HOOK include/linux/netfilter.h:297 [inline] > ipv6_rcv+0x250/0x380 net/ipv6/ip6_input.c:309 > __netif_receive_skb_one_core+0x114/0x180 net/core/dev.c:5491 > __netif_receive_skb+0x1f/0x1c0 net/core/dev.c:5605 > netif_receive_skb_internal net/core/dev.c:5691 [inline] > netif_receive_skb+0x133/0x7a0 net/core/dev.c:5750 > tun_rx_batched+0x4b3/0x7a0 drivers/net/tun.c:1553 > tun_get_user+0x2452/0x39c0 drivers/net/tun.c:1989 > tun_chr_write_iter+0xdf/0x200 drivers/net/tun.c:2035 > call_write_iter include/linux/fs.h:1868 [inline] > new_sync_write fs/read_write.c:491 [inline] > vfs_write+0x945/0xd50 fs/read_write.c:584 > ksys_write+0x12b/0x250 fs/read_write.c:637 > do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] > __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 > do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 > entry_SYSENTER_compat_after_hwframe+0x70/0x82 > RIP: 0023:0xf7f21579 > Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 > RSP: 002b:00000000f7f1c590 EFLAGS: 00000282 ORIG_RAX: 0000000000000004 > RAX: ffffffffffffffda RBX: 00000000000000c8 RCX: 0000000020000040 > RDX: 0000000000000083 RSI: 00000000f734e000 RDI: 0000000000000000 > RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 > R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 > </TASK> > Modules linked in: > ---[ end trace 0000000000000000 ]--- > RIP: 0010:sk_get_rmem0 include/net/sock.h:2907 [inline] > RIP: 0010:__sk_mem_raise_allocated+0x806/0x17a0 net/core/sock.c:3006 > Code: c1 ea 03 80 3c 02 00 0f 85 23 0f 00 00 48 8b 44 24 08 48 8b 98 38 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 <0f> b6 14 02 48 89 d8 83 e0 07 83 c0 03 38 d0 0f 8d 6f 0a 00 00 8b > RSP: 0018:ffffc90005d7f450 EFLAGS: 00010246 > RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc90004d92000 > RDX: 0000000000000000 RSI: ffffffff88066482 RDI: ffffffff8e2ccbb8 > RBP: ffff8880173f7000 R08: 0000000000000005 R09: 0000000000000000 > R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000030000 > R13: 0000000000000001 R14: 0000000000000340 R15: 0000000000000001 > FS: 0000000000000000(0000) GS:ffff8880b9800000(0063) knlGS:00000000f7f1cb40 > CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033 > CR2: 000000002e82f000 CR3: 0000000034ff0000 CR4: 00000000003506f0 > ---------------- > Code disassembly (best guess): > 0: c1 ea 03 shr $0x3,%edx > 3: 80 3c 02 00 cmpb $0x0,(%rdx,%rax,1) > 7: 0f 85 23 0f 00 00 jne 0xf30 > d: 48 8b 44 24 08 mov 0x8(%rsp),%rax > 12: 48 8b 98 38 01 00 00 mov 0x138(%rax),%rbx > 19: 48 b8 00 00 00 00 00 movabs $0xdffffc0000000000,%rax > 20: fc ff df > 23: 48 89 da mov %rbx,%rdx > 26: 48 c1 ea 03 shr $0x3,%rdx > * 2a: 0f b6 14 02 movzbl (%rdx,%rax,1),%edx <-- trapping instruction > 2e: 48 89 d8 mov %rbx,%rax > 31: 83 e0 07 and $0x7,%eax > 34: 83 c0 03 add $0x3,%eax > 37: 38 d0 cmp %dl,%al > 39: 0f 8d 6f 0a 00 00 jge 0xaae > 3f: 8b .byte 0x8b > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > > If the bug is already fixed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want to change bug's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the bug is a duplicate of another bug, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup
