Re: [syzbot] [mm?] WARNING in raw_ioctl

[Gopi Krishna Menon <krishnagopi487@gmail.com>]

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On Fri, Oct 24, 2025 at 04:11:28PM -0700, syzbot wrote:

> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    72fb0170ef1f Add linux-next specific files for 20251024
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=10fd0be2580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=e812d103f45aa955
> dashboard link: https://syzkaller.appspot.com/bug?extid=d8fd35fa6177afa8c92b
> compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=119eae7c580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=140693e2580000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/be1fa3d1f761/disk-72fb0170.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/57302bf7af40/vmlinux-72fb0170.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/91c806bb2a2b/bzImage-72fb0170.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+d8fd35fa6177afa8c92b@syzkaller.appspotmail.com
> 
> ------------[ cut here ]------------
> WARNING: mm/page_alloc.c:5190 at __alloc_frozen_pages_noprof+0x2c8/0x370 mm/page_alloc.c:5190, CPU#1: syz.0.17/6001
> Modules linked in:
> CPU: 1 UID: 0 PID: 6001 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) 
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
> RIP: 0010:__alloc_frozen_pages_noprof+0x2c8/0x370 mm/page_alloc.c:5190
> Code: 74 10 4c 89 e7 89 54 24 0c e8 64 b9 0d 00 8b 54 24 0c 49 83 3c 24 00 0f 85 a5 fe ff ff e9 a6 fe ff ff c6 05 b1 7d 70 0d 01 90 <0f> 0b 90 e9 18 ff ff ff a9 00 00 08 00 48 8b 4c 24 10 4c 8d 44 24
> RSP: 0018:ffffc90003017920 EFLAGS: 00010246
> RAX: ffffc90003017900 RBX: 0000000000000013 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc90003017988
> RBP: ffffc90003017a18 R08: ffffc90003017987 R09: 0000000000000000
> R10: ffffc90003017960 R11: fffff52000602f31 R12: 0000000000000000
> R13: 1ffff92000602f28 R14: 0000000000040cc0 R15: dffffc0000000000
> FS:  000055558dedb500(0000) GS:ffff888125ddc000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007ffef4504a80 CR3: 0000000072ffa000 CR4: 00000000003526f0
> Call Trace:
>  <TASK>
>  alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2418
>  ___kmalloc_large_node+0x5f/0x1b0 mm/slub.c:5583
>  __kmalloc_large_node_noprof+0x18/0x90 mm/slub.c:5614
>  __do_kmalloc_node mm/slub.c:5630 [inline]
>  __kmalloc_noprof+0x4c9/0x800 mm/slub.c:5654
>  kmalloc_noprof include/linux/slab.h:961 [inline]
>  raw_alloc_io_data drivers/usb/gadget/legacy/raw_gadget.c:673 [inline]
>  raw_ioctl_ep_read drivers/usb/gadget/legacy/raw_gadget.c:1162 [inline]
>  raw_ioctl+0x18fb/0x3be0 drivers/usb/gadget/legacy/raw_gadget.c:1325
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:597 [inline]
>  __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7fccefd8efc9
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffef4505ad8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007fcceffe5fa0 RCX: 00007fccefd8efc9
> RDX: 00002000000000c0 RSI: 00000000c0085508 RDI: 0000000000000004
> RBP: 00007fccefe11f91 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007fcceffe5fa0 R14: 00007fcceffe5fa0 R15: 0000000000000003
>  </TASK>
> 
> 
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@googlegroups.com.
> 
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> 
> If the report is already addressed, let syzbot know by replying with:
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> 
> If you want syzbot to run the reproducer, reply with:
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> If you attach or paste a git patch, syzbot will apply it before testing.
> 
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Since the maximum packet size of the endpoint descriptor is a 16 bit
field, we can make sure that the io->length is never greater than 65535
bytes.

Resend the patch as attachement as earlier one got cut off by syzbot.

#syz test


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From 06149314c2d71c1a6481db9a0fba98d4509cde6a Mon Sep 17 00:00:00 2001
From: Gopi Krishna Menon <krishnagopi487@gmail.com>
Date: Sat, 25 Oct 2025 18:55:45 +0530
Subject: [PATCH] usb: raw_gadget: validate io length in raw_alloc_io_data()

Since the maximum packet size of the endpoint descriptor is a 16 bit
field, we can make sure that the io->length is never greater than 65535
bytes.

For testing in syzbot

Signed-off-by: Gopi Krishna Menon <krishnagopi487@gmail.com>
---
 drivers/usb/gadget/legacy/raw_gadget.c | 2 ++
 include/uapi/linux/usb/raw_gadget.h    | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/drivers/usb/gadget/legacy/raw_gadget.c b/drivers/usb/gadget/legacy/raw_gadget.c
index b71680c58de6..00f5e697d321 100644
--- a/drivers/usb/gadget/legacy/raw_gadget.c
+++ b/drivers/usb/gadget/legacy/raw_gadget.c
@@ -667,6 +667,8 @@ static void *raw_alloc_io_data(struct usb_raw_ep_io *io, void __user *ptr,
 		return ERR_PTR(-EINVAL);
 	if (!usb_raw_io_flags_valid(io->flags))
 		return ERR_PTR(-EINVAL);
+	if (io->length > USB_RAW_IO_MAX_LENGTH)
+		return ERR_PTR(-EINVAL);
 	if (get_from_user)
 		data = memdup_user(ptr + sizeof(*io), io->length);
 	else {
diff --git a/include/uapi/linux/usb/raw_gadget.h b/include/uapi/linux/usb/raw_gadget.h
index f0224a8dc858..effe8a543c75 100644
--- a/include/uapi/linux/usb/raw_gadget.h
+++ b/include/uapi/linux/usb/raw_gadget.h
@@ -106,6 +106,9 @@ struct usb_raw_ep_io {
 /* Maximum number of non-control endpoints in struct usb_raw_eps_info. */
 #define USB_RAW_EPS_NUM_MAX	30
 
+/* Maximum length for raw endpoint IO */
+#define USB_RAW_IO_MAX_LENGTH 65535
+
 /* Maximum length of UDC endpoint name in struct usb_raw_ep_info. */
 #define USB_RAW_EP_NAME_MAX	16
 
-- 
2.43.0