[v6.6] general protection fault in rebind_store

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: c5596480c50e Linux 6.6.145
git tree: linux-6.6.y
console output: https://syzkaller.appspot.com/x/log.txt?x=108331b9580000
kernel config: https://syzkaller.appspot.com/x/.config?x=f0bc3d90c30838b5
dashboard link: https://syzkaller.appspot.com/bug?extid=8b7b221b303bc78f159c
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/eb5cda0a8020/disk-c5596480.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ca05ff2fc502/vmlinux-c5596480.xz
kernel image: https://storage.googleapis.com/syzbot-assets/6daf3255b985/bzImage-c5596480.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8b7b22...@syzkaller.appspotmail.com

general protection fault, probably for non-canonical address 0xdffffc000000001d: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef]
CPU: 0 PID: 13625 Comm: syz.5.2641 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026
RIP: 0010:do_rebind drivers/usb/usbip/stub_main.c:204 [inline]
RIP: 0010:rebind_store+0xc7/0x240 drivers/usb/usbip/stub_main.c:264
Code: 83 c7 30 4d 89 fd 49 c1 ed 03 41 80 7c 2d 00 00 74 08 4c 89 ff e8 e9 e0 06 fb 41 bc e8 00 00 00 4d 03 27 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 cb e0 06 fb 4d 8b 24 24 4d 85 e4 0f
RSP: 0018:ffffc9000501fc78 EFLAGS: 00010206
RAX: 000000000000001d RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000000ffffffff
RBP: dffffc0000000000 R08: ffffffff9765f503 R09: 1ffffffff2ecbea0
R10: dffffc0000000000 R11: fffffbfff2ecbea1 R12: 00000000000000e8
R13: 1ffffffff2ecbe9e R14: ffff888141e4a000 R15: ffffffff9765f4f0
FS: 00007fc4b02636c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fe4fa800000 CR3: 000000004826c000 CR4: 00000000003506f0
Call Trace:
<TASK>
kernfs_fop_write_iter+0x3a4/0x520 fs/kernfs/file.c:352
call_write_iter include/linux/fs.h:2018 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x474/0x9a0 fs/read_write.c:584
ksys_write+0x151/0x260 fs/read_write.c:637
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc4af39de99
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:00007fc4b0263028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fc4af625fa0 RCX: 00007fc4af39de99
RDX: 0000000000000001 RSI: 0000200000000200 RDI: 0000000000000003
RBP: 00007fc4af433eaf R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fc4af626038 R14: 00007fc4af625fa0 R15: 00007ffde3ba1c78
</TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:do_rebind drivers/usb/usbip/stub_main.c:204 [inline]
RIP: 0010:rebind_store+0xc7/0x240 drivers/usb/usbip/stub_main.c:264
Code: 83 c7 30 4d 89 fd 49 c1 ed 03 41 80 7c 2d 00 00 74 08 4c 89 ff e8 e9 e0 06 fb 41 bc e8 00 00 00 4d 03 27 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 cb e0 06 fb 4d 8b 24 24 4d 85 e4 0f
RSP: 0018:ffffc9000501fc78 EFLAGS: 00010206
RAX: 000000000000001d RBX: 0000000000000001 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 00000000ffffffff
RBP: dffffc0000000000 R08: ffffffff9765f503 R09: 1ffffffff2ecbea0
R10: dffffc0000000000 R11: fffffbfff2ecbea1 R12: 00000000000000e8
R13: 1ffffffff2ecbe9e R14: ffff888141e4a000 R15: ffffffff9765f4f0
FS: 00007fc4b02636c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3ec7eb CR3: 000000004826c000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
0: 83 c7 30 add $0x30,%edi
3: 4d 89 fd mov %r15,%r13
6: 49 c1 ed 03 shr $0x3,%r13
a: 41 80 7c 2d 00 00 cmpb $0x0,0x0(%r13,%rbp,1)
10: 74 08 je 0x1a
12: 4c 89 ff mov %r15,%rdi
15: e8 e9 e0 06 fb call 0xfb06e103
1a: 41 bc e8 00 00 00 mov $0xe8,%r12d
20: 4d 03 27 add (%r15),%r12
23: 4c 89 e0 mov %r12,%rax
26: 48 c1 e8 03 shr $0x3,%rax
* 2a: 80 3c 28 00 cmpb $0x0,(%rax,%rbp,1) <-- trapping instruction
2e: 74 08 je 0x38
30: 4c 89 e7 mov %r12,%rdi
33: e8 cb e0 06 fb call 0xfb06e103
38: 4d 8b 24 24 mov (%r12),%r12
3c: 4d 85 e4 test %r12,%r12
3f: 0f .byte 0xf


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