[syzbot] WARNING in remove_proc_entry (5)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 80bd9028feca Add linux-next specific files for 20230131
git tree: linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=10a0f7ae480000
kernel config: https://syzkaller.appspot.com/x/.config?x=904dc2f450eaad4a
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

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/924618188238/disk-80bd9028.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/7a03cf86e545/vmlinux-80bd9028.xz
kernel image: https://storage.googleapis.com/syzbot-assets/568e80043a41/bzImage-80bd9028.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+04a843...@syzkaller.appspotmail.com

------------[ cut here ]------------
name 'gss_krb5_enctypes'
WARNING: CPU: 0 PID: 6187 at fs/proc/generic.c:712 remove_proc_entry+0x38d/0x460 fs/proc/generic.c:712
Modules linked in:
CPU: 0 PID: 6187 Comm: syz-executor.4 Not tainted 6.2.0-rc6-next-20230131-syzkaller-09515-g80bd9028feca #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023
RIP: 0010:remove_proc_entry+0x38d/0x460 fs/proc/generic.c:712
Code: e9 6d fe ff ff e8 63 f1 7c ff 48 c7 c7 e0 6d 98 8c e8 47 ba 0b 08 e8 52 f1 7c ff 4c 89 e6 48 c7 c7 c0 85 5e 8a e8 53 8c 44 ff <0f> 0b e9 a4 fe ff ff e8 37 f1 7c ff 48 8d bd d8 00 00 00 48 b8 00
RSP: 0018:ffffc90015dcf8c8 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 1ffff92002bb9f1b RCX: ffffc9000c579000
RDX: 0000000000040000 RSI: ffffffff81692aec RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000000 R12: ffffffff8b75c440
R13: dffffc0000000000 R14: dffffc0000000000 R15: fffffbfff1c6d918
FS: 00007fe943910700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2d14a16984 CR3: 0000000029c4e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
destroy_krb5_enctypes_proc_entry net/sunrpc/auth_gss/svcauth_gss.c:1543 [inline]
gss_svc_shutdown_net+0x7d/0x2b0 net/sunrpc/auth_gss/svcauth_gss.c:2120
ops_exit_list+0xb0/0x170 net/core/net_namespace.c:169
setup_net+0x9bd/0xe60 net/core/net_namespace.c:356
copy_net_ns+0x320/0x6b0 net/core/net_namespace.c:483
create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
copy_namespaces+0x410/0x500 kernel/nsproxy.c:179
copy_process+0x311d/0x76b0 kernel/fork.c:2272
kernel_clone+0xeb/0x9a0 kernel/fork.c:2684
__do_sys_clone+0xba/0x100 kernel/fork.c:2825
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fe942c8c0c9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe943910118 EFLAGS: 00000206 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fe942dabf80 RCX: 00007fe942c8c0c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000071801000
RBP: 00007fe942ce7ae9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 00007ffe8ccafb1f R14: 00007fe943910300 R15: 0000000000022000
</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 syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

[syzbot]

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: syzbot+04a843...@syzkaller.appspotmail.com

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>

[Hillf Danton]

On 12 Mar 2023 21:07:47 -0700

> HEAD commit: 134231664868 Merge tag 'staging-6.3-rc2' of git://git.kern..
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17ecb766c80000

Make scsi_proc_host_add() return error.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 134231664868

diff -pur e/drivers/scsi/hosts.c f/drivers/scsi/hosts.c
--- e/drivers/scsi/hosts.c 2023-03-13 16:36:31.771360300 +0800
+++ f/drivers/scsi/hosts.c 2023-03-13 16:55:43.487554000 +0800
@@ -180,7 +180,8 @@ void scsi_remove_host(struct Scsi_Host *
flush_workqueue(shost->tmf_work_q);
scsi_forget_host(shost);
mutex_unlock(&shost->scan_mutex);
- scsi_proc_host_rm(shost);
+ if (shost->has_proc_entry)
+ scsi_proc_host_rm(shost);
scsi_proc_hostdir_rm(shost->hostt);

/*
@@ -308,7 +309,7 @@ int scsi_add_host_with_dma(struct Scsi_H
if (error)
goto out_del_dev;

- scsi_proc_host_add(shost);
+ shost->has_proc_entry = scsi_proc_host_add(shost) ? 0 : 1;
scsi_autopm_put_host(shost);
return error;

diff -pur e/drivers/scsi/scsi_priv.h f/drivers/scsi/scsi_priv.h
--- e/drivers/scsi/scsi_priv.h 2023-03-13 16:35:13.115863300 +0800
+++ f/drivers/scsi/scsi_priv.h 2023-03-13 16:42:38.599849800 +0800
@@ -113,14 +113,14 @@ extern void scsi_evt_thread(struct work_
#ifdef CONFIG_SCSI_PROC_FS
extern int scsi_proc_hostdir_add(const struct scsi_host_template *);
extern void scsi_proc_hostdir_rm(const struct scsi_host_template *);
-extern void scsi_proc_host_add(struct Scsi_Host *);
+extern int scsi_proc_host_add(struct Scsi_Host *);
extern void scsi_proc_host_rm(struct Scsi_Host *);
extern int scsi_init_procfs(void);
extern void scsi_exit_procfs(void);
#else
# define scsi_proc_hostdir_add(sht) 0
# define scsi_proc_hostdir_rm(sht) do { } while (0)
-# define scsi_proc_host_add(shost) do { } while (0)
+# define scsi_proc_host_add(shost) (0)
# define scsi_proc_host_rm(shost) do { } while (0)
# define scsi_init_procfs() (0)
# define scsi_exit_procfs() do { } while (0)
diff -pur e/drivers/scsi/scsi_proc.c f/drivers/scsi/scsi_proc.c
--- e/drivers/scsi/scsi_proc.c 2023-03-13 16:44:34.303439700 +0800
+++ f/drivers/scsi/scsi_proc.c 2023-03-13 16:50:16.629024700 +0800
@@ -215,7 +215,7 @@ void scsi_proc_hostdir_rm(const struct s
* scsi_proc_host_add - Add entry for this host to appropriate /proc dir
* @shost: host to add
*/
-void scsi_proc_host_add(struct Scsi_Host *shost)
+int scsi_proc_host_add(struct Scsi_Host *shost)
{
const struct scsi_host_template *sht = shost->hostt;
struct scsi_proc_entry *e;
@@ -223,7 +223,7 @@ void scsi_proc_host_add(struct Scsi_Host
char name[10];

if (!sht->show_info)
- return;
+ return -ENXIO;

e = scsi_lookup_proc_entry(sht);
if (!e)
@@ -234,12 +234,13 @@ void scsi_proc_host_add(struct Scsi_Host
&proc_scsi_ops, shost);
if (!p)
goto err;
- return;

+ return 0;
err:
shost_printk(KERN_ERR, shost,
"%s: Failed to register host (%s failed)\n", __func__,
e ? "proc_create_data()" : "scsi_proc_hostdir_add()");
+ return -ENXIO;
}

/**
diff -pur e/include/scsi/scsi_host.h f/include/scsi/scsi_host.h
--- e/include/scsi/scsi_host.h 2023-03-13 16:33:13.890534300 +0800
+++ f/include/scsi/scsi_host.h 2023-03-13 16:38:22.230851100 +0800
@@ -659,6 +659,8 @@ struct Scsi_Host {
/* The transport requires the LUN bits NOT to be stored in CDB[1] */
unsigned no_scsi2_lun_in_cdb:1;

+ unsigned has_proc_entry:1;
+
/*
* Optional work queue to be utilized by the transport
*/
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in remove_proc_entry

------------[ cut here ]------------
remove_proc_entry: removing non-empty directory 'scsi/ums-sddr09', leaking at least '3'
WARNING: CPU: 1 PID: 5626 at fs/proc/generic.c:718 remove_proc_entry+0x361/0x460 fs/proc/generic.c:718
Modules linked in:
CPU: 1 PID: 5626 Comm: kworker/1:7 Not tainted 6.3.0-rc1-syzkaller-00274-g134231664868-dirty #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+0x361/0x460 fs/proc/generic.c:718
Code: fa 48 c1 ea 03 80 3c 02 00 0f 85 be 00 00 00 49 8b 94 24 d8 00 00 00 48 c7 c6 40 ac 5e 8a 48 c7 c7 60 ab 5e 8a e8 5f df 42 ff <0f> 0b e9 6d fe ff ff e8 c3 c2 7a ff 48 c7 c7 c0 68 99 8c e8 f7 e9
RSP: 0018:ffffc90005ec7650 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 1ffff92000bd8ecc RCX: 0000000000000000
RDX: ffff888020808000 RSI: ffffffff814bf3a7 RDI: 0000000000000001
RBP: ffff88807c1e4c80 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff8880177e9b40
R13: ffff88807c1e4d38 R14: ffff88823bd68ff8 R15: 0000000000000000

FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033

CR2: 00007f209e780ff8 CR3: 0000000029ee1000 CR4: 00000000003506e0

DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>

scsi_proc_hostdir_rm+0x107/0x280 drivers/scsi/scsi_proc.c:206
scsi_host_dev_release+0xc9/0x3b0 drivers/scsi/hosts.c:346
device_release+0xa3/0x240 drivers/base/core.c:2436
kobject_cleanup lib/kobject.c:681 [inline]
kobject_release lib/kobject.c:712 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x1c2/0x4d0 lib/kobject.c:729
put_device+0x1f/0x30 drivers/base/core.c:3697

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>

Tested on:

commit: 13423166 Merge tag 'staging-6.3-rc2' of git://git.kern..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=13eabf24c80000

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

patch: https://syzkaller.appspot.com/x/patch.diff?x=13a7ceecc80000

[Hillf Danton]

On 12 Mar 2023 21:07:47 -0700

> HEAD commit: 134231664868 Merge tag 'staging-6.3-rc2' of git://git.kern..
> git tree: upstream

> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17ecb766c80000

Make scsi_proc_host_add() return error.

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 134231664868

diff -pur e/drivers/scsi/hosts.c f/drivers/scsi/hosts.c
--- e/drivers/scsi/hosts.c 2023-03-13 16:36:31.771360300 +0800

+++ f/drivers/scsi/hosts.c 2023-03-13 19:55:41.210607500 +0800
@@ -180,8 +180,14 @@ void scsi_remove_host(struct Scsi_Host *

flush_workqueue(shost->tmf_work_q);
scsi_forget_host(shost);
mutex_unlock(&shost->scan_mutex);
- scsi_proc_host_rm(shost);

- scsi_proc_hostdir_rm(shost->hostt);
+ if (shost->has_proc_entry) {
+ shost->has_proc_entry = 0;
+ scsi_proc_host_rm(shost);
+ }
+ if (shost->has_proc_dir) {
+ shost->has_proc_dir = 0;
+ scsi_proc_hostdir_rm(shost->hostt);
+ }

/*
* New SCSI devices cannot be attached anymore because of the SCSI host
@@ -308,7 +314,7 @@ int scsi_add_host_with_dma(struct Scsi_H

if (error)
goto out_del_dev;

- scsi_proc_host_add(shost);
+ shost->has_proc_entry = scsi_proc_host_add(shost) ? 0 : 1;
scsi_autopm_put_host(shost);
return error;

@@ -342,7 +348,8 @@ static void scsi_host_dev_release(struct
struct device *parent = dev->parent;

/* In case scsi_remove_host() has not been called. */
- scsi_proc_hostdir_rm(shost->hostt);
+ if (shost->has_proc_dir)
+ scsi_proc_hostdir_rm(shost->hostt);

/* Wait for functions invoked through call_rcu(&scmd->rcu, ...) */
rcu_barrier();
@@ -521,8 +528,10 @@ struct Scsi_Host *scsi_host_alloc(struct
"failed to create tmf workq\n");
goto fail;
}
+ shost->has_proc_dir = 0;
if (scsi_proc_hostdir_add(shost->hostt) < 0)
goto fail;
+ shost->has_proc_dir = 1;
return shost;
fail:
/*

+++ f/include/scsi/scsi_host.h 2023-03-13 19:52:24.441709800 +0800

@@ -659,6 +659,8 @@ struct Scsi_Host {
/* The transport requires the LUN bits NOT to be stored in CDB[1] */
unsigned no_scsi2_lun_in_cdb:1;

+ unsigned has_proc_entry:1;

+ unsigned has_proc_dir:1;

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-and-tested-by: syzbot+04a843...@syzkaller.appspotmail.com

Tested on:

commit: 13423166 Merge tag 'staging-6.3-rc2' of git://git.kern..
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git

console output: https://syzkaller.appspot.com/x/log.txt?x=159f590cc80000

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

patch: https://syzkaller.appspot.com/x/patch.diff?x=12fe5fdac80000

Note: testing is done by a robot and is best-effort only.