[syzbot] [net?] WARNING: refcount bug in new_device_store

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 2f1baf1fc892 Merge tag 'trace-v7.2-rc7' of git://git.kerne..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=170d8a25580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c44651ea7dd2f307
dashboard link: https://syzkaller.appspot.com/bug?extid=989ff6506f5c6d1ff56b
compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=148d8a25580000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+989ff6...@syzkaller.appspotmail.com

</TASK>
kobject: kobject_add_internal failed for netdevsim1 (error: -12 parent: devices)
------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: lib/refcount.c:25 at refcount_warn_saturate+0x111/0x130 lib/refcount.c:25, CPU#2: syz-executor324/6031
Modules linked in:
CPU: 2 UID: 0 PID: 6031 Comm: syz-executor324 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
RIP: 0010:refcount_warn_saturate+0x111/0x130 lib/refcount.c:25
Code: 06 e8 b3 92 ec fc 48 8d 3d bc c2 0e 0c 67 48 0f b9 3a e8 a2 92 ec fc 5b 5d c3 cc cc cc cc e8 96 92 ec fc 48 8d 3d af c2 0e 0c <67> 48 0f b9 3a e8 85 92 ec fc 5b 5d c3 cc cc cc cc 48 89 df e8 36
RSP: 0018:ffffc90003587b80 EFLAGS: 00010293
RAX: 0000000000000000 RBX: ffffffff9ba33900 RCX: ffffffff851de03b
RDX: ffff88802a11a540 RSI: ffffffff851de0ea RDI: ffffffff912ca3a0
RBP: 0000000000000002 R08: 0000000000000005 R09: 0000000000000004
R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000005
R13: 0000000000000000 R14: 0000000000000002 R15: 0000000000000001
FS: 000055558c1ff400(0000) GS:ffff8880d5fe9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000558dbbbdfda8 CR3: 000000003f842000 CR4: 0000000000352ef0
Call Trace:
<TASK>
__refcount_add include/linux/refcount.h:289 [inline]
__refcount_inc include/linux/refcount.h:366 [inline]
refcount_inc include/linux/refcount.h:383 [inline]
new_device_store+0x682/0x700 drivers/net/netdevsim/bus.c:197
bus_attr_store+0x74/0xb0 drivers/base/bus.c:172
sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x6ac/0x1050 fs/read_write.c:687
ksys_pwrite64 fs/read_write.c:794 [inline]
__do_sys_pwrite64 fs/read_write.c:802 [inline]
__se_sys_pwrite64 fs/read_write.c:799 [inline]
__x64_sys_pwrite64+0x1eb/0x250 fs/read_write.c:799
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff5691f4237
Code: 48 89 fa 4c 89 df e8 98 1d 00 00 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 1a 5b c3 0f 1f 84 00 00 00 00 00 48 8b 44 24 10 0f 05 <5b> c3 0f 1f 80 00 00 00 00 83 e2 39 83 fa 08 75 de e8 23 ff ff ff
RSP: 002b:00007fffaed29530 EFLAGS: 00000202 ORIG_RAX: 0000000000000012
RAX: ffffffffffffffda RBX: 000055558c1ff400 RCX: 00007ff5691f4237
RDX: 0000000000000005 RSI: 00007ff56922d0cd RDI: 0000000000000004
RBP: 0000000000000004 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000003
R13: 00007fffaed29580 R14: 0000000000000007 R15: 00007ff56922d4c2
</TASK>
----------------
Code disassembly (best guess), 1 bytes skipped:
0: e8 b3 92 ec fc call 0xfcec92b8
5: 48 8d 3d bc c2 0e 0c lea 0xc0ec2bc(%rip),%rdi # 0xc0ec2c8
c: 67 48 0f b9 3a ud1 (%edx),%rdi
11: e8 a2 92 ec fc call 0xfcec92b8
16: 5b pop %rbx
17: 5d pop %rbp
18: c3 ret
19: cc int3
1a: cc int3
1b: cc int3
1c: cc int3
1d: e8 96 92 ec fc call 0xfcec92b8
22: 48 8d 3d af c2 0e 0c lea 0xc0ec2af(%rip),%rdi # 0xc0ec2d8
* 29: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction
2e: e8 85 92 ec fc call 0xfcec92b8
33: 5b pop %rbx
34: 5d pop %rbp
35: c3 ret
36: cc int3
37: cc int3
38: cc int3
39: cc int3
3a: 48 89 df mov %rbx,%rdi
3d: e8 .byte 0xe8
3e: 36 ss


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