Subject: Re: [syzbot] [scsi?] WARNING in remove_proc_entry (5)

From: syzbot <[email-masked]>
Date: Sun, 12 Mar 2023 21:07:47 -0700

syzbot has found a reproducer for the following issue on:

HEAD commit:    134231664868 Merge tag 'staging-6.3-rc2' of git://git.kern..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=16ae091ac80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8aef547e348b1ab8
dashboard link: https://syzkaller.appspot.com/bug?extid=04a8437497bcfb4afa95
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=13f21b2ac80000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17ecb766c80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/810b18cfd92d/disk-13423166.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/49409dbd680c/vmlinux-13423166.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c4a589bbe527/bzImage-13423166.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

name '2'
WARNING: CPU: 1 PID: 26 at fs/proc/generic.c:712 remove_proc_entry+0x38d/0x460 fs/proc/generic.c:712
Modules linked in:
CPU: 1 PID: 26 Comm: kworker/1:1 Not tainted 6.3.0-rc1-syzkaller-00274-g134231664868 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/02/2023
Workqueue: usb_hub_wq hub_event
RIP: 0010:remove_proc_entry+0x38d/0x460 fs/proc/generic.c:712
Code: e9 6d fe ff ff e8 c3 c2 7a ff 48 c7 c7 c0 68 99 8c e8 f7 e9 08 08 e8 b2 c2 7a ff 4c 89 e6 48 c7 c7 00 a8 5e 8a e8 33 df 42 ff <0f> 0b e9 a4 fe ff ff e8 97 c2 7a ff 48 8d bd d8 00 00 00 48 b8 00
RSP: 0018:ffffc90000a1f638 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 1ffff92000143ec9 RCX: 0000000000000000
RDX: ffff8880174e1d40 RSI: ffffffff814bf3a7 RDI: 0000000000000001
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffffc90000a1f710
R13: dffffc0000000000 R14: ffff88807abf4078 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f84e0c354b8 CR3: 00000000788c7000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 scsi_proc_host_rm+0x15d/0x1d0 drivers/scsi/scsi_proc.c:263
 scsi_remove_host+0x108/0x340 drivers/scsi/hosts.c:183
 quiesce_and_remove_host drivers/usb/storage/usb.c:867 [inline]
 usb_stor_disconnect+0x119/0x270 drivers/usb/storage/usb.c:1087
 usb_unbind_interface+0x1dc/0x8e0 drivers/usb/core/driver.c:458
 device_remove drivers/base/dd.c:542 [inline]
 device_remove+0x11f/0x170 drivers/base/dd.c:534
 __device_release_driver drivers/base/dd.c:1240 [inline]
 device_release_driver_internal+0x443/0x610 drivers/base/dd.c:1263
 bus_remove_device+0x22c/0x420 drivers/base/bus.c:574
 device_del+0x48a/0xb80 drivers/base/core.c:3775
 usb_disable_device+0x35a/0x7b0 drivers/usb/core/message.c:1420
 usb_disconnect+0x2db/0x8a0 drivers/usb/core/hub.c:2238
 hub_port_connect drivers/usb/core/hub.c:5246 [inline]
 hub_port_connect_change drivers/usb/core/hub.c:5551 [inline]
 port_event drivers/usb/core/hub.c:5711 [inline]
 hub_event+0x1fbf/0x4e40 drivers/usb/core/hub.c:5793
 process_one_work+0x991/0x1710 kernel/workqueue.c:2390
 process_scheduled_works kernel/workqueue.c:2453 [inline]
 worker_thread+0x858/0x1090 kernel/workqueue.c:2539
 kthread+0x2e8/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308
 </TASK>