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From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Date: Wed, 27 Mar 2024 08:19:52 -0700
Message-ID: <CAADnVQLpJwEfLoF9ORc7bSsDPG7Y05mWUpWWyfi7qjY+2LhC+Q@mail.gmail.com>
Subject: Re: [syzbot] [bpf?] [net?] general protection fault in dev_map_enqueue
To: syzbot <syzbot+af9492708df9797198d6@syzkaller.appspotmail.com>, 
	=?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= <toke@kernel.org>, 
	Jesper Dangaard Brouer <hawk@kernel.org>
Cc: andrii@kernel.org, ast@kernel.org, bpf@vger.kernel.org, 
	daniel@iogearbox.net, davem@davemloft.net, eddyz87@gmail.com, 
	haoluo@google.com, john.fastabend@gmail.com, jolsa@kernel.org, 
	kpsingh@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, 
	martin.lau@linux.dev, netdev@vger.kernel.org, sdf@google.com, song@kernel.org, 
	syzkaller-bugs@googlegroups.com, yonghong.song@linux.dev
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Toke, Jesper,

please take a look.
It's reproducible 100% of the time.
dst is NULL in dev_map_enqueue().

Thanks

On Wed, Mar 27, 2024 at 1:10=E2=80=AFAM syzbot
<syzbot+af9492708df9797198d6@syzkaller.appspotmail.com> wrote:
>
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit:    443574b03387 riscv, bpf: Fix kfunc parameters incompatibi=
l..
> git tree:       bpf
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=3D17d370b118000=
0
> kernel config:  https://syzkaller.appspot.com/x/.config?x=3D6fb1be60a193d=
440
> dashboard link: https://syzkaller.appspot.com/bug?extid=3Daf9492708df9797=
198d6
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Deb=
ian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=3D13d6b041180=
000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=3D1060cc8118000=
0
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/3f355021a085/dis=
k-443574b0.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/44cf4de7472a/vmlinu=
x-443574b0.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/a99a36c7ad65/b=
zImage-443574b0.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the comm=
it:
> Reported-by: syzbot+af9492708df9797198d6@syzkaller.appspotmail.com
>
> general protection fault, probably for non-canonical address 0xdffffc0000=
000000: 0000 [#1] PREEMPT SMP KASAN PTI
> KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> CPU: 1 PID: 5078 Comm: syz-executor295 Not tainted 6.8.0-syzkaller-05236-=
g443574b03387 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS G=
oogle 02/29/2024
> RIP: 0010:dev_map_enqueue+0x31/0x3e0 kernel/bpf/devmap.c:539
> Code: 41 56 41 55 41 54 53 48 83 ec 18 49 89 d4 49 89 f5 48 89 fd 49 be 0=
0 00 00 00 00 fc ff df e8 a6 42 d8 ff 48 89 e8 48 c1 e8 03 <42> 80 3c 30 00=
 74 08 48 89 ef e8 10 8a 3b 00 4c 8b 7d 00 48 83 c5
> RSP: 0018:ffffc90003bef688 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888022169e00
> RDX: 0000000000000000 RSI: ffff88802ef65070 RDI: 0000000000000000
> RBP: 0000000000000000 R08: 0000000000000005 R09: ffffffff894ff90e
> R10: 0000000000000004 R11: ffff888022169e00 R12: ffff888015bd0000
> R13: ffff88802ef65070 R14: dffffc0000000000 R15: ffff8880b953c088
> FS:  000055558e3b9380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000=
000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f1141b380d0 CR3: 0000000021838000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>  <TASK>
>  __xdp_do_redirect_frame net/core/filter.c:4384 [inline]
>  xdp_do_redirect_frame+0x20d/0x4d0 net/core/filter.c:4438
>  xdp_test_run_batch net/bpf/test_run.c:336 [inline]
>  bpf_test_run_xdp_live+0xe8a/0x1e90 net/bpf/test_run.c:384
>  bpf_prog_test_run_xdp+0x813/0x11b0 net/bpf/test_run.c:1267
>  bpf_prog_test_run+0x33a/0x3b0 kernel/bpf/syscall.c:4240
>  __sys_bpf+0x48d/0x810 kernel/bpf/syscall.c:5649
>  __do_sys_bpf kernel/bpf/syscall.c:5738 [inline]
>  __se_sys_bpf kernel/bpf/syscall.c:5736 [inline]
>  __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5736
>  do_syscall_64+0xfb/0x240
>  entry_SYSCALL_64_after_hwframe+0x6d/0x75
> RIP: 0033:0x7f1141ac0fb9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 17 00 00 90 48 89 f8 48 89 f=
7 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 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffe180a1958 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
> RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f1141ac0fb9
> RDX: 0000000000000048 RSI: 0000000020000340 RDI: 000000000000000a
> RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000006
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001
>  </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:dev_map_enqueue+0x31/0x3e0 kernel/bpf/devmap.c:539
> Code: 41 56 41 55 41 54 53 48 83 ec 18 49 89 d4 49 89 f5 48 89 fd 49 be 0=
0 00 00 00 00 fc ff df e8 a6 42 d8 ff 48 89 e8 48 c1 e8 03 <42> 80 3c 30 00=
 74 08 48 89 ef e8 10 8a 3b 00 4c 8b 7d 00 48 83 c5
> RSP: 0018:ffffc90003bef688 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888022169e00
> RDX: 0000000000000000 RSI: ffff88802ef65070 RDI: 0000000000000000
> RBP: 0000000000000000 R08: 0000000000000005 R09: ffffffff894ff90e
> R10: 0000000000000004 R11: ffff888022169e00 R12: ffff888015bd0000
> R13: ffff88802ef65070 R14: dffffc0000000000 R15: ffff8880b953c088
> FS:  000055558e3b9380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000=
000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007f1141b380d0 CR3: 0000000021838000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> ----------------
> Code disassembly (best guess):
>    0:   41 56                   push   %r14
>    2:   41 55                   push   %r13
>    4:   41 54                   push   %r12
>    6:   53                      push   %rbx
>    7:   48 83 ec 18             sub    $0x18,%rsp
>    b:   49 89 d4                mov    %rdx,%r12
>    e:   49 89 f5                mov    %rsi,%r13
>   11:   48 89 fd                mov    %rdi,%rbp
>   14:   49 be 00 00 00 00 00    movabs $0xdffffc0000000000,%r14
>   1b:   fc ff df
>   1e:   e8 a6 42 d8 ff          call   0xffd842c9
>   23:   48 89 e8                mov    %rbp,%rax
>   26:   48 c1 e8 03             shr    $0x3,%rax
> * 2a:   42 80 3c 30 00          cmpb   $0x0,(%rax,%r14,1) <-- trapping in=
struction
>   2f:   74 08                   je     0x39
>   31:   48 89 ef                mov    %rbp,%rdi
>   34:   e8 10 8a 3b 00          call   0x3b8a49
>   39:   4c 8b 7d 00             mov    0x0(%rbp),%r15
>   3d:   48                      rex.W
>   3e:   83                      .byte 0x83
>   3f:   c5                      .byte 0xc5
>
>
> ---
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.