Subject: [syzbot] linux-next test error: general protection fault in xfrm_policy_lookup_bytype

From: syzbot <[email-masked]>
Date: Mon, 21 Nov 2022 05:47:38 -0800

Hello,

syzbot found the following issue on:

HEAD commit:    e4cd8d3ff7f9 Add linux-next specific files for 20221121
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1472370d880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a0ebedc6917bacc1
dashboard link: https://syzkaller.appspot.com/bug?extid=bfb2bee01b9c01fff864
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b59eb967701d/disk-e4cd8d3f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/37a7b43e6e84/vmlinux-e4cd8d3f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/ebfb0438e6a2/bzImage-e4cd8d3f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

general protection fault, probably for non-canonical address 0xdffffc0000000019: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000c8-0x00000000000000cf]
CPU: 0 PID: 5295 Comm: kworker/0:3 Not tainted 6.1.0-rc5-next-20221121-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Workqueue: ipv6_addrconf addrconf_dad_work
RIP: 0010:xfrm_policy_lookup_bytype.cold+0x1c/0x54 net/xfrm/xfrm_policy.c:2139
Code: 80 44 28 8e e8 9a 88 37 fa e9 28 e7 7b fe e8 c0 25 7a f7 49 8d bf cc 00 00 00 b8 ff ff 37 00 48 89 fa 48 c1 e0 2a 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1c 41
RSP: 0018:ffffc90003cdf1e0 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000019 RSI: ffffffff8a068150 RDI: 00000000000000cc
RBP: 0000000000000000 R08: 0000000000000007 R09: fffffffffffff000
R10: 0000000000000000 R11: 0000000000000005 R12: 0000000000000000
R13: ffff88802ae78000 R14: ffffed10055cf2ff R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb5cb893300 CR3: 00000000714fb000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 xfrm_policy_lookup net/xfrm/xfrm_policy.c:2151 [inline]
 xfrm_bundle_lookup net/xfrm/xfrm_policy.c:2958 [inline]
 xfrm_lookup_with_ifid+0x39b/0x20f0 net/xfrm/xfrm_policy.c:3099
 xfrmi_xmit2 net/xfrm/xfrm_interface.c:404 [inline]
 xfrmi_xmit+0x3c7/0x1b90 net/xfrm/xfrm_interface.c:521
 __netdev_start_xmit include/linux/netdevice.h:4859 [inline]
 netdev_start_xmit include/linux/netdevice.h:4873 [inline]
 xmit_one net/core/dev.c:3583 [inline]
 dev_hard_start_xmit+0x1c2/0x990 net/core/dev.c:3599
 __dev_queue_xmit+0x2cdf/0x3ba0 net/core/dev.c:4249
 dev_queue_xmit include/linux/netdevice.h:3029 [inline]
 neigh_connected_output+0x3c4/0x520 net/core/neighbour.c:1600
 neigh_output include/net/neighbour.h:546 [inline]
 ip6_finish_output2+0x56c/0x1530 net/ipv6/ip6_output.c:134
 __ip6_finish_output net/ipv6/ip6_output.c:195 [inline]
 ip6_finish_output+0x694/0x1170 net/ipv6/ip6_output.c:206
 NF_HOOK_COND include/linux/netfilter.h:291 [inline]
 ip6_output+0x1f1/0x540 net/ipv6/ip6_output.c:227
 dst_output include/net/dst.h:444 [inline]
 NF_HOOK include/linux/netfilter.h:302 [inline]
 ndisc_send_skb+0xa63/0x1740 net/ipv6/ndisc.c:508
 ndisc_send_rs+0x132/0x6f0 net/ipv6/ndisc.c:718
 addrconf_dad_completed+0x37a/0xda0 net/ipv6/addrconf.c:4248
 addrconf_dad_begin net/ipv6/addrconf.c:4014 [inline]
 addrconf_dad_work+0x820/0x12d0 net/ipv6/addrconf.c:4116
 process_one_work+0x9bf/0x1710 kernel/workqueue.c:2289
 worker_thread+0x669/0x1090 kernel/workqueue.c:2436
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:xfrm_policy_lookup_bytype.cold+0x1c/0x54 net/xfrm/xfrm_policy.c:2139
Code: 80 44 28 8e e8 9a 88 37 fa e9 28 e7 7b fe e8 c0 25 7a f7 49 8d bf cc 00 00 00 b8 ff ff 37 00 48 89 fa 48 c1 e0 2a 48 c1 ea 03 <0f> b6 14 02 48 89 f8 83 e0 07 83 c0 03 38 d0 7c 04 84 d2 75 1c 41
RSP: 0018:ffffc90003cdf1e0 EFLAGS: 00010203
RAX: dffffc0000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000019 RSI: ffffffff8a068150 RDI: 00000000000000cc
RBP: 0000000000000000 R08: 0000000000000007 R09: fffffffffffff000
R10: 0000000000000000 R11: 0000000000000005 R12: 0000000000000000
R13: ffff88802ae78000 R14: ffffed10055cf2ff R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fb5cb893300 CR3: 00000000714fb000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess), 1 bytes skipped:
   0:	44 28 8e e8 9a 88 37 	sub    %r9b,0x37889ae8(%rsi)
   7:	fa                   	cli
   8:	e9 28 e7 7b fe       	jmpq   0xfe7be735
   d:	e8 c0 25 7a f7       	callq  0xf77a25d2
  12:	49 8d bf cc 00 00 00 	lea    0xcc(%r15),%rdi
  19:	b8 ff ff 37 00       	mov    $0x37ffff,%eax
  1e:	48 89 fa             	mov    %rdi,%rdx
  21:	48 c1 e0 2a          	shl    $0x2a,%rax
  25:	48 c1 ea 03          	shr    $0x3,%rdx
* 29:	0f b6 14 02          	movzbl (%rdx,%rax,1),%edx <-- trapping instruction
  2d:	48 89 f8             	mov    %rdi,%rax
  30:	83 e0 07             	and    $0x7,%eax
  33:	83 c0 03             	add    $0x3,%eax
  36:	38 d0                	cmp    %dl,%al
  38:	7c 04                	jl     0x3e
  3a:	84 d2                	test   %dl,%dl
  3c:	75 1c                	jne    0x5a
  3e:	41                   	rex.B

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