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From: syzbot ci <syzbot+ci232191c023a10d57@syzkaller.appspotmail.com>
To: aleksander.lobakin@intel.com, andrii@kernel.org, ast@kernel.org,
	 bpf@vger.kernel.org, daniel@iogearbox.net, davem@davemloft.net,
	 dddddd@hust.edu.cn, dzm91@hust.edu.cn, eddyz87@gmail.com,
	edumazet@google.com,  haoluo@google.com, hawk@kernel.org,
	horms@kernel.org,  john.fastabend@gmail.com, jolsa@kernel.org,
	kafai.wan@linux.dev,  kpsingh@kernel.org, kuba@kernel.org,
	linux-kernel@vger.kernel.org,  linux-kselftest@vger.kernel.org,
	m202472210@hust.edu.cn, martin.lau@linux.dev,
	 netdev@vger.kernel.org, pabeni@redhat.com, sdf@fomichev.me,
	shuah@kernel.org,  song@kernel.org, toke@redhat.com,
	yonghong.song@linux.dev
Cc: syzbot@lists.linux.dev, syzkaller-bugs@googlegroups.com
Subject: [syzbot ci] Re: bpf, test_run: Fix user-memory-access vulnerability for LIVE_FRAMES
Date: Mon, 05 Jan 2026 00:07:48 -0800	[thread overview]
Message-ID: <695b7154.050a0220.a1b6.039c.GAE@google.com> (raw)
In-Reply-To: <20260104162350.347403-1-kafai.wan@linux.dev>

syzbot ci has tested the following series

[v1] bpf, test_run: Fix user-memory-access vulnerability for LIVE_FRAMES
https://lore.kernel.org/all/20260104162350.347403-1-kafai.wan@linux.dev
* [PATCH bpf-next 1/2] bpf, test_run: Fix user-memory-access vulnerability for LIVE_FRAMES
* [PATCH bpf-next 2/2] selftests/bpf: Add test for xdp_md context with LIVE_FRAMES in BPF_PROG_TEST_RUN

and found the following issue:
BUG: missing reserved tailroom

Full report is available here:
https://ci.syzbot.org/series/688d9198-9fed-495e-9113-3d4187428ee3

***

BUG: missing reserved tailroom

tree:      bpf-next
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/bpf/bpf-next.git
base:      a069190b590e108223cd841a1c2d0bfb92230ecc
arch:      amd64
compiler:  Debian clang version 21.1.8 (++20251202083448+f68f64eb8130-1~exp1~20251202083504.46), Debian LLD 21.1.8
config:    https://ci.syzbot.org/builds/3375fbfc-d3f8-45a8-8db2-62ac76ebb7b4/config
C repro:   https://ci.syzbot.org/findings/37614d32-0f44-4a1c-9822-586c95cfeb11/c_repro
syz repro: https://ci.syzbot.org/findings/37614d32-0f44-4a1c-9822-586c95cfeb11/syz_repro

------------[ cut here ]------------
XDP_WARN: xdp_update_frame_from_buff(line:414): Driver BUG: missing reserved tailroom
WARNING: net/core/xdp.c:618 at xdp_warn+0x1d/0x40 net/core/xdp.c:618, CPU#1: syz.0.17/5990
Modules linked in:
CPU: 1 UID: 0 PID: 5990 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
RIP: 0010:xdp_warn+0x25/0x40 net/core/xdp.c:618
Code: 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 53 89 d3 49 89 f6 49 89 ff e8 da 83 63 f8 48 8d 3d e3 de 70 06 4c 89 f6 89 da 4c 89 f9 <67> 48 0f b9 3a 5b 41 5e 41 5f c3 cc cc cc cc cc 66 66 2e 0f 1f 84
RSP: 0018:ffffc90004427580 EFLAGS: 00010293
RAX: ffffffff895fc996 RBX: 000000000000019e RCX: ffffffff8c94c7e0
RDX: 000000000000019e RSI: ffffffff8da38c06 RDI: ffffffff8fd0a880
RBP: 0000000000000f68 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8881b4ae3ec0
R13: ffff8881b4ae3198 R14: ffffffff8da38c06 R15: ffffffff8c94c7e0
FS:  000055555699b500(0000) GS:ffff8882a9a1f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b30463fff CR3: 0000000175022000 CR4: 00000000000006f0
Call Trace:
 <TASK>
 xdp_update_frame_from_buff include/net/xdp.h:414 [inline]
 xdp_test_run_init_page+0x482/0x590 net/bpf/test_run.c:143
 page_pool_set_pp_info net/core/page_pool.c:716 [inline]
 __page_pool_alloc_netmems_slow+0x33c/0x710 net/core/page_pool.c:631
 page_pool_alloc_netmems net/core/page_pool.c:667 [inline]
 page_pool_alloc_pages+0xe6/0x1f0 net/core/page_pool.c:675
 page_pool_dev_alloc_pages include/net/page_pool/helpers.h:96 [inline]
 xdp_test_run_batch net/bpf/test_run.c:294 [inline]
 bpf_test_run_xdp_live+0x714/0x1cf0 net/bpf/test_run.c:378
 bpf_prog_test_run_xdp+0x7d2/0x1120 net/bpf/test_run.c:1387
 bpf_prog_test_run+0x2c7/0x340 kernel/bpf/syscall.c:4698
 __sys_bpf+0x643/0x950 kernel/bpf/syscall.c:6220
 __do_sys_bpf kernel/bpf/syscall.c:6315 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:6313 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:6313
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xf0/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f389319acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc43c08dd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f3893405fa0 RCX: 00007f389319acb9
RDX: 0000000000000048 RSI: 0000200000000600 RDI: 000000000000000a
RBP: 00007f3893208bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f3893405fac R14: 00007f3893405fa0 R15: 00007f3893405fa0
 </TASK>
----------------
Code disassembly (best guess):
   0:	90                   	nop
   1:	90                   	nop
   2:	90                   	nop
   3:	90                   	nop
   4:	90                   	nop
   5:	f3 0f 1e fa          	endbr64
   9:	41 57                	push   %r15
   b:	41 56                	push   %r14
   d:	53                   	push   %rbx
   e:	89 d3                	mov    %edx,%ebx
  10:	49 89 f6             	mov    %rsi,%r14
  13:	49 89 ff             	mov    %rdi,%r15
  16:	e8 da 83 63 f8       	call   0xf86383f5
  1b:	48 8d 3d e3 de 70 06 	lea    0x670dee3(%rip),%rdi        # 0x670df05
  22:	4c 89 f6             	mov    %r14,%rsi
  25:	89 da                	mov    %ebx,%edx
  27:	4c 89 f9             	mov    %r15,%rcx
* 2a:	67 48 0f b9 3a       	ud1    (%edx),%rdi <-- trapping instruction
  2f:	5b                   	pop    %rbx
  30:	41 5e                	pop    %r14
  32:	41 5f                	pop    %r15
  34:	c3                   	ret
  35:	cc                   	int3
  36:	cc                   	int3
  37:	cc                   	int3
  38:	cc                   	int3
  39:	cc                   	int3
  3a:	66                   	data16
  3b:	66                   	data16
  3c:	2e                   	cs
  3d:	0f                   	.byte 0xf
  3e:	1f                   	(bad)
  3f:	84                   	.byte 0x84


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
  Tested-by: syzbot@syzkaller.appspotmail.com

---
This report is generated by a bot. It may contain errors.
syzbot ci engineers can be reached at syzkaller@googlegroups.com.

      parent reply	other threads:[~2026-01-05  8:07 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <fa2be179-bad7-4ee3-8668-4903d1853461@hust.edu.cn>
2026-01-04 16:23 ` [PATCH bpf-next 0/2] bpf, test_run: Fix user-memory-access vulnerability for LIVE_FRAMES KaFai Wan
2026-01-04 16:23   ` [PATCH bpf-next 1/2] " KaFai Wan
2026-01-05 10:46     ` Toke Høiland-Jørgensen
2026-01-05 13:22       ` KaFai Wan
2026-01-05 16:43         ` Toke Høiland-Jørgensen
2026-01-06 13:53           ` KaFai Wan
2026-01-04 16:23   ` [PATCH bpf-next 2/2] selftests/bpf: Add test for xdp_md context with LIVE_FRAMES in BPF_PROG_TEST_RUN KaFai Wan
2026-01-05  8:07   ` syzbot ci [this message]

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