Re: [syzbot] general protection fault in hwsim_new_edge_nl

[Dongliang Mu]

On Mon, Aug 9, 2021 at 3:54 PM syzbot
<syzbot+fafb46da3f65fdbacd16@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    c2eecaa193ff pktgen: Remove redundant clone_skb override
> git tree:       net-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1226099a300000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=aba0c23f8230e048
> dashboard link: https://syzkaller.appspot.com/bug?extid=fafb46da3f65fdbacd16
> compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+fafb46da3f65fdbacd16@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]

Hi all,

I think the crash can be fixed by [PATCH] ieee802154: hwsim: fix GPF
in hwsim_new_edge_nl [1]. For now, it is in the wpan tree.

[1] https://lkml.org/lkml/2021/7/8/66

> CPU: 1 PID: 1403 Comm: syz-executor.2 Not tainted 5.14.0-rc3-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> RIP: 0010:nla_len include/net/netlink.h:1148 [inline]
> RIP: 0010:nla_parse_nested_deprecated include/net/netlink.h:1231 [inline]
> RIP: 0010:hwsim_new_edge_nl+0xf4/0x8c0 drivers/net/ieee802154/mac802154_hwsim.c:425
> Code: 00 0f 85 76 07 00 00 4d 85 ed 48 8b 5b 10 0f 84 5e 05 00 00 e8 0d f2 40 fc 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 14 02 48 89 d8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 87
> RSP: 0018:ffffc90009a47568 EFLAGS: 00010246
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000dd59000
> RDX: 0000000000000000 RSI: ffffffff8534ab43 RDI: ffff88801c2b44d0
> RBP: ffffc90009a47678 R08: 0000000000000001 R09: ffffc90009a476a8
> R10: fffff52001348ed6 R11: 0000000000000000 R12: ffffc90009a47698
> R13: ffff888025945c14 R14: ffff888071f0cdc0 R15: 0000000000000000
> FS:  00007f8448923700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00000000032f4708 CR3: 0000000033eed000 CR4: 00000000001506e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:731
>  genl_family_rcv_msg net/netlink/genetlink.c:775 [inline]
>  genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:792
>  netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2504
>  genl_rcv+0x24/0x40 net/netlink/genetlink.c:803
>  netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline]
>  netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1340
>  netlink_sendmsg+0x86d/0xdb0 net/netlink/af_netlink.c:1929
>  sock_sendmsg_nosec net/socket.c:704 [inline]
>  sock_sendmsg+0xcf/0x120 net/socket.c:724
>  ____sys_sendmsg+0x6e8/0x810 net/socket.c:2403
>  ___sys_sendmsg+0xf3/0x170 net/socket.c:2457
>  __sys_sendmsg+0xe5/0x1b0 net/socket.c:2486
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x44/0xae
> RIP: 0033:0x4665e9
> 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 bc ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f8448923188 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
> RDX: 0000000000000000 RSI: 0000000020001ac0 RDI: 0000000000000004
> RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
> R13: 00007ffd8ac8e60f R14: 00007f8448923300 R15: 0000000000022000
> Modules linked in:
> ---[ end trace d1679fe789931133 ]---
> RIP: 0010:nla_len include/net/netlink.h:1148 [inline]
> RIP: 0010:nla_parse_nested_deprecated include/net/netlink.h:1231 [inline]
> RIP: 0010:hwsim_new_edge_nl+0xf4/0x8c0 drivers/net/ieee802154/mac802154_hwsim.c:425
> Code: 00 0f 85 76 07 00 00 4d 85 ed 48 8b 5b 10 0f 84 5e 05 00 00 e8 0d f2 40 fc 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 <0f> b6 14 02 48 89 d8 83 e0 07 83 c0 01 38 d0 7c 08 84 d2 0f 85 87
> RSP: 0018:ffffc90009a47568 EFLAGS: 00010246
> RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffc9000dd59000
> RDX: 0000000000000000 RSI: ffffffff8534ab43 RDI: ffff88801c2b44d0
> RBP: ffffc90009a47678 R08: 0000000000000001 R09: ffffc90009a476a8
> R10: fffff52001348ed6 R11: 0000000000000000 R12: ffffc90009a47698
> R13: ffff888025945c14 R14: ffff888071f0cdc0 R15: 0000000000000000
> FS:  00007f8448923700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000055bb2ea2f160 CR3: 0000000033eed000 CR4: 00000000001506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
> ---
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