Re: [syzbot] [bpf?] [net?] KASAN: slab-use-after-free Read in bq_xmit_all

[Jesper Dangaard Brouer <hawk@kernel.org>]

On 19/07/2024 07.12, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    73399b58e5e5 Add linux-next specific files for 20240718
> git tree:       linux-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=111f2195980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=54e443ddc2b981c8
> dashboard link: https://syzkaller.appspot.com/bug?extid=707d98c8649695eaf329
> 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=1602cf31980000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=106fde5e980000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/fbab059c854f/disk-73399b58.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/874a209f4c3f/vmlinux-73399b58.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/f34e5c7be278/bzImage-73399b58.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+707d98c8649695eaf329@syzkaller.appspotmail.com
> 
> ------------[ cut here ]------------
> UBSAN: array-index-out-of-bounds in ./kernel/bpf/devmap.c:385:28
> index 16 is out of range for type 'struct xdp_frame *[16]'
> CPU: 1 UID: 0 PID: 5101 Comm: syz-executor232 Not tainted 6.10.0-next-20240718-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
> Call Trace:
>   <IRQ>
>   __dump_stack lib/dump_stack.c:94 [inline]
>   dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
>   ubsan_epilogue lib/ubsan.c:231 [inline]
>   __ubsan_handle_out_of_bounds+0x121/0x150 lib/ubsan.c:429
>   bq_xmit_all+0x157/0x11d0 kernel/bpf/devmap.c:385
>   __dev_flush+0x81/0x160 kernel/bpf/devmap.c:425
>   xdp_do_check_flushed+0x129/0x240 net/core/filter.c:4300

When xdp_do_check_flushed() calls __dev_flush(), this indicate that some 
driver didn't call xdp_do_flush() after NAPI finished.

What NIC device driver is this tested on?

--Jesper

>   __napi_poll+0xe4/0x490 net/core/dev.c:6774
>   napi_poll net/core/dev.c:6840 [inline]
>   net_rx_action+0x89b/0x1240 net/core/dev.c:6962
>   handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
>   __do_softirq kernel/softirq.c:588 [inline]
>   invoke_softirq kernel/softirq.c:428 [inline]
>   __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
>   irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
>   common_interrupt+0xaa/0xd0 arch/x86/kernel/irq.c:278
>   </IRQ>
>   <TASK>
>   asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
> RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
> RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194
> Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 ce cf 5c f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> c3 69 c4 f5 65 8b 05 04 5f 65 74 85 c0 74 43 48 c7 04 24 0e 36
> RSP: 0018:ffffc9000369fb60 EFLAGS: 00000206
> RAX: 3e45100d05912800 RBX: 1ffff920006d3f70 RCX: ffffffff817023ea
> RDX: dffffc0000000000 RSI: ffffffff8bcad5c0 RDI: 0000000000000001
> RBP: ffffc9000369fbf0 R08: ffffffff9300f817 R09: 1ffffffff2601f02
> R10: dffffc0000000000 R11: fffffbfff2601f03 R12: dffffc0000000000
> R13: 1ffff920006d3f6c R14: ffffc9000369fb80 R15: 0000000000000246
>   spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
>   do_notify_parent_cldstop+0x9ab/0xb50 kernel/signal.c:2216
>   ptrace_stop+0x465/0x940 kernel/signal.c:2319
>   ptrace_do_notify kernel/signal.c:2393 [inline]
>   ptrace_notify+0x255/0x380 kernel/signal.c:2405
>   ptrace_report_syscall include/linux/ptrace.h:415 [inline]
>   ptrace_report_syscall_entry include/linux/ptrace.h:452 [inline]
>   syscall_trace_enter+0x5d/0x150 kernel/entry/common.c:45
>   syscall_enter_from_user_mode_work include/linux/entry-common.h:168 [inline]
>   syscall_enter_from_user_mode include/linux/entry-common.h:198 [inline]
>   do_syscall_64+0xcc/0x230 arch/x86/entry/common.c:79
>   entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f708ebe0e20
> Code: ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 80 3d 81 e2 07 00 00 74 17 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c
> RSP: 002b:00007ffd97b2a878 EFLAGS: 00000202 ORIG_RAX: 0000000000000003
> RAX: ffffffffffffffda RBX: 0000000000000015 RCX: 00007f708ebe0e20
> RDX: ffffffffffffffb8 RSI: 0000000020000240 RDI: 0000000000000014
> RBP: 0000000000000000 R08: 00007ffd97b2a9a8 R09: 00007ffd97b2a9a8
> R10: 00007ffd97b2a9a8 R11: 0000000000000202 R12: 0000000000000000
> R13: 0000000000000000 R14: 00007ffd97b2a8b0 R15: 00007ffd97b2a8a0
>   </TASK>
> ---[ end trace ]---
> ----------------
> Code disassembly (best guess):
>     0:	9c                   	pushf
>     1:	8f 44 24 20          	pop    0x20(%rsp)
>     5:	42 80 3c 23 00       	cmpb   $0x0,(%rbx,%r12,1)
>     a:	74 08                	je     0x14
>     c:	4c 89 f7             	mov    %r14,%rdi
>     f:	e8 ce cf 5c f6       	call   0xf65ccfe2
>    14:	f6 44 24 21 02       	testb  $0x2,0x21(%rsp)
>    19:	75 52                	jne    0x6d
>    1b:	41 f7 c7 00 02 00 00 	test   $0x200,%r15d
>    22:	74 01                	je     0x25
>    24:	fb                   	sti
>    25:	bf 01 00 00 00       	mov    $0x1,%edi
> * 2a:	e8 c3 69 c4 f5       	call   0xf5c469f2 <-- trapping instruction
>    2f:	65 8b 05 04 5f 65 74 	mov    %gs:0x74655f04(%rip),%eax        # 0x74655f3a
>    36:	85 c0                	test   %eax,%eax
>    38:	74 43                	je     0x7d
>    3a:	48                   	rex.W
>    3b:	c7                   	.byte 0xc7
>    3c:	04 24                	add    $0x24,%al
>    3e:	0e                   	(bad)
>    3f:	36                   	ss
> 
> 
> ---
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