linux-kernel - [syzbot] [net?] [bpf?] general protection fault in xdp_do_generic

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Message-ID: <000000000000fd3017061c7a405c@google.com>
Date: Thu, 04 Jul 2024 23:34:22 -0700
From: syzbot <syzbot+380f7022f450dd776e64@...kaller.appspotmail.com>
To: andrii@...nel.org, ast@...nel.org, bpf@...r.kernel.org, 
	daniel@...earbox.net, davem@...emloft.net, eddyz87@...il.com, 
	edumazet@...gle.com, haoluo@...gle.com, john.fastabend@...il.com, 
	jolsa@...nel.org, kpsingh@...nel.org, kuba@...nel.org, 
	linux-kernel@...r.kernel.org, martin.lau@...ux.dev, netdev@...r.kernel.org, 
	pabeni@...hat.com, sdf@...ichev.me, song@...nel.org, 
	syzkaller-bugs@...glegroups.com, yonghong.song@...ux.dev
Subject: [syzbot] [net?] [bpf?] general protection fault in xdp_do_generic_redirect

Hello,

syzbot found the following issue on:

HEAD commit:    0b58e108042b Add linux-next specific files for 20240703
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15de4eb9980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ed034204f2e40e53
dashboard link: https://syzkaller.appspot.com/bug?extid=380f7022f450dd776e64
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/1d079762feae/disk-0b58e108.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/e53996c8d8c2/vmlinux-0b58e108.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a0bf21cdd844/bzImage-0b58e108.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+380f7022f450dd776e64@...kaller.appspotmail.com

Oops: general protection fault, probably for non-canonical address 0xdffffc0000000007: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000038-0x000000000000003f]
CPU: 0 UID: 0 PID: 8647 Comm: syz.3.1455 Not tainted 6.10.0-rc6-next-20240703-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
RIP: 0010:bpf_net_ctx_get_ri include/linux/filter.h:788 [inline]
RIP: 0010:xdp_do_generic_redirect+0x7e/0x8f0 net/core/filter.c:4525
Code: 3c 01 00 74 12 48 89 df e8 9f 26 90 f8 48 b8 00 00 00 00 00 fc ff df 48 89 5c 24 48 48 8b 1b 4c 8d 73 38 4d 89 f7 49 c1 ef 03 <41> 0f b6 04 07 84 c0 0f 85 37 06 00 00 41 8b 2e 89 ee 83 e6 02 31
RSP: 0018:ffffc900094777f8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1100fd9f6c0
RDX: ffffc900042a9000 RSI: 0000000000001ab7 RDI: 0000000000001ab8
RBP: ffffc900094779b0 R08: 0000000000000005 R09: ffffffff89601c5e
R10: 0000000000000003 R11: ffff88807ecf9e00 R12: ffffc90009477b60
R13: 1ffff9200128ef1c R14: 0000000000000038 R15: 0000000000000007
FS:  00007fa9faca56c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020011000 CR3: 000000002c750000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 do_xdp_generic+0x884/0xb90 net/core/dev.c:5138
 tun_get_user+0x2805/0x4560 drivers/net/tun.c:1924
 tun_chr_write_iter+0x113/0x1f0 drivers/net/tun.c:2048
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa72/0xc90 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa9f9f7475f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 29 8c 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 7c 8c 02 00 48
RSP: 002b:00007fa9faca5010 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa9fa103f60 RCX: 00007fa9f9f7475f
RDX: 000000000000fdef RSI: 0000000020001540 RDI: 00000000000000c8
RBP: 00007fa9f9fe4aa1 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000fdef R11: 0000000000000293 R12: 0000000000000000
R13: 000000000000000b R14: 00007fa9fa103f60 R15: 00007fff952046f8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:bpf_net_ctx_get_ri include/linux/filter.h:788 [inline]
RIP: 0010:xdp_do_generic_redirect+0x7e/0x8f0 net/core/filter.c:4525
Code: 3c 01 00 74 12 48 89 df e8 9f 26 90 f8 48 b8 00 00 00 00 00 fc ff df 48 89 5c 24 48 48 8b 1b 4c 8d 73 38 4d 89 f7 49 c1 ef 03 <41> 0f b6 04 07 84 c0 0f 85 37 06 00 00 41 8b 2e 89 ee 83 e6 02 31
RSP: 0018:ffffc900094777f8 EFLAGS: 00010202
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 1ffff1100fd9f6c0
RDX: ffffc900042a9000 RSI: 0000000000001ab7 RDI: 0000000000001ab8
RBP: ffffc900094779b0 R08: 0000000000000005 R09: ffffffff89601c5e
R10: 0000000000000003 R11: ffff88807ecf9e00 R12: ffffc90009477b60
R13: 1ffff9200128ef1c R14: 0000000000000038 R15: 0000000000000007
FS:  00007fa9faca56c0(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020011000 CR3: 000000002c750000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	3c 01                	cmp    $0x1,%al
   2:	00 74 12 48          	add    %dh,0x48(%rdx,%rdx,1)
   6:	89 df                	mov    %ebx,%edi
   8:	e8 9f 26 90 f8       	call   0xf89026ac
   d:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  14:	fc ff df
  17:	48 89 5c 24 48       	mov    %rbx,0x48(%rsp)
  1c:	48 8b 1b             	mov    (%rbx),%rbx
  1f:	4c 8d 73 38          	lea    0x38(%rbx),%r14
  23:	4d 89 f7             	mov    %r14,%r15
  26:	49 c1 ef 03          	shr    $0x3,%r15
* 2a:	41 0f b6 04 07       	movzbl (%r15,%rax,1),%eax <-- trapping instruction
  2f:	84 c0                	test   %al,%al
  31:	0f 85 37 06 00 00    	jne    0x66e
  37:	41 8b 2e             	mov    (%r14),%ebp
  3a:	89 ee                	mov    %ebp,%esi
  3c:	83 e6 02             	and    $0x2,%esi
  3f:	31                   	.byte 0x31


---
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