[syzbot] [fs?] WARNING in sysfs_emit_at

[syzbot <syzbot+b6445765657b5855e869@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    c8ed9b5c02a5 Merge tag 'drm-fixes-2025-09-05' of https://g..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=112eba42580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fecbb496f75d3d61
dashboard link: https://syzkaller.appspot.com/bug?extid=b6445765657b5855e869
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11ba0962580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=15e2a962580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4da8d56aff3a/disk-c8ed9b5c.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1366baa37dbc/vmlinux-c8ed9b5c.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0674b31d870d/bzImage-c8ed9b5c.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+b6445765657b5855e869@syzkaller.appspotmail.com

------------[ cut here ]------------
invalid sysfs_emit_at: buf:ffff88803234000a at:10
WARNING: CPU: 0 PID: 6027 at fs/sysfs/file.c:795 sysfs_emit_at+0xe6/0x1a0 fs/sysfs/file.c:795
Modules linked in:
CPU: 0 UID: 0 PID: 6027 Comm: syz.0.18 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:sysfs_emit_at+0xe6/0x1a0 fs/sysfs/file.c:795
Code: ff 0f 00 00 4c 89 fe e8 28 e3 5a ff 4d 85 ff 74 68 e8 ae e7 5a ff 90 48 c7 c7 20 66 c3 8b 44 89 e2 48 89 de e8 2b de 19 ff 90 <0f> 0b 90 90 31 db e8 8f e7 5a ff 48 b8 00 00 00 00 00 fc ff df 49
RSP: 0018:ffffc90003d6f860 EFLAGS: 00010286
RAX: 0000000000000000 RBX: ffff88803234000a RCX: ffffffff817a02f8
RDX: ffff888032578000 RSI: ffffffff817a0305 RDI: 0000000000000001
RBP: ffffc90003d6f938 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 000000000000000a
R13: 1ffff920007adf0c R14: ffffffff8c742680 R15: 000000000000000a
FS:  000055556eb34500(0000) GS:ffff8881246bd000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000040 CR3: 0000000071308000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 usb_show_dynids+0x17e/0x220 drivers/usb/core/driver.c:126
 drv_attr_show+0x6c/0xa0 drivers/base/bus.c:113
 sysfs_kf_seq_show+0x213/0x3e0 fs/sysfs/file.c:65
 traverse.part.0.constprop.0+0x107/0x640 fs/seq_file.c:111
 traverse fs/seq_file.c:98 [inline]
 seq_read_iter+0x932/0x12c0 fs/seq_file.c:195
 kernfs_fop_read_iter+0x40f/0x5a0 fs/kernfs/file.c:279
 copy_splice_read+0x618/0xc20 fs/splice.c:363
 do_splice_read fs/splice.c:982 [inline]
 do_splice_read+0x282/0x370 fs/splice.c:956
 splice_file_to_pipe+0x109/0x120 fs/splice.c:1292
 do_sendfile+0x400/0xe50 fs/read_write.c:1376
 __do_sys_sendfile64 fs/read_write.c:1431 [inline]
 __se_sys_sendfile64 fs/read_write.c:1417 [inline]
 __x64_sys_sendfile64+0x1d8/0x220 fs/read_write.c:1417
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f645838ebe9
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:00007ffedc1827c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f64585c5fa0 RCX: 00007f645838ebe9
RDX: 0000000000000000 RSI: 0000000000000003 RDI: 0000000000000001
RBP: 00007f6458411e19 R08: 0000000000000000 R09: 0000000000000000
R10: 000000007ffff000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f64585c5fa0 R14: 00007f64585c5fa0 R15: 0000000000000004
 </TASK>


---
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