On 27/03/2024 16.19, Alexei Starovoitov wrote:
Toke, Jesper,
please take a look.
It's reproducible 100% of the time.
dst is NULL in dev_map_enqueue().
The `dst` (NULL) is basically `ri->tgt_value` being passed through
(unmodified) via xdp_do_redirect_frame() and __xdp_do_redirect_frame()
into dev_map_enqueue().
I think something is wrong in xdp_test_run_batch().
The `ri->tgt_value` is being set in __bpf_xdp_redirect_map(), but I
cannot see __bpf_xdp_redirect_map() being used in xdp_test_run_batch().
Toke, can you take a look at xdp_test_run_batch() and where
`ri->tgt_value` is getting set?
On Wed, Mar 27, 2024 at 1:10 AM syzbot
<syzbot+af9492708df9797198d6@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
syzbot has found a reproducer for the following issue on:
HEAD commit: 443574b03387 riscv, bpf: Fix kfunc parameters incompatibil..
git tree: bpf
console+strace: https://syzkaller.appspot.com/x/log.txt?x=17d370b1180000
kernel config: https://syzkaller.appspot.com/x/.config?x=6fb1be60a193d440
dashboard link: https://syzkaller.appspot.com/bug?extid=af9492708df9797198d6
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=13d6b041180000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1060cc81180000
Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/3f355021a085/disk-443574b0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/44cf4de7472a/vmlinux-443574b0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a99a36c7ad65/bzImage-443574b0.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+af9492708df9797198d6@xxxxxxxxxxxxxxxxxxxxxxxxx
general protection fault, probably for non-canonical address 0xdffffc0000000000: 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 Google 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 00 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:0000000000000000
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 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 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 00 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:0000000000000000
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 instruction
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
---
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