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Subject: Re: [PATCH] usbip: fix warning in vhci_hcd_probe/lockdep_init_map
To: Andrey Konovalov <andreyknvl@google.com>
References: <20161205195638.7005-1-shuahkh@osg.samsung.com>
Cc: gregkh@linuxfoundation.org, valentina.manea.m@gmail.com,
        shuah@kernel.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org, Shuah Khan <shuahkh@osg.samsung.com>
From: Shuah Khan <shuahkh@osg.samsung.com>
Message-ID: <4a3b7e4f-6b5c-d9e8-f26c-1286d4e1f630@osg.samsung.com>
Date: Mon, 5 Dec 2016 13:00:31 -0700
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Hi Andrey,

On 12/05/2016 12:56 PM, Shuah Khan wrote:
> vhci_hcd calls sysfs_create_group() with dynamically allocated sysfs
> attributes triggering the lock-class key not persistent warning. Call
> sysfs_attr_init() for dynamically allocated sysfs attributes to fix it.
> 
> vhci_hcd vhci_hcd: USB/IP Virtual Host Controller
> vhci_hcd vhci_hcd: new USB bus registered, assigned bus number 2
> BUG: key ffff88006a7e8d18 not in .data!
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 1 at kernel/locking/lockdep.c:3131
> lockdep_init_map+0x60c/0x770
> DEBUG_LOCKS_WARN_ON(1)[    1.567044] Modules linked in:
> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.9.0-rc7+ #58
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
>  ffff88006bce6eb8 ffffffff81f96c8a ffffffff00000a02 1ffff1000d79cd6a
>  ffffed000d79cd62 000000046bce6ed8 0000000041b58ab3 ffffffff8598af40
>  ffffffff81f969f8 0000000000000000 0000000041b58ab3 0000000000000200
> Call Trace:
>  [<     inline     >] __dump_stack lib/dump_stack.c:15
>  [<ffffffff81f96c8a>] dump_stack+0x292/0x398 lib/dump_stack.c:51
>  [<ffffffff812b808f>] __warn+0x19f/0x1e0 kernel/panic.c:550
>  [<ffffffff812b8195>] warn_slowpath_fmt+0xc5/0x110 kernel/panic.c:565
>  [<ffffffff813f3efc>] lockdep_init_map+0x60c/0x770 kernel/locking/lockdep.c:3131
>  [<ffffffff819e43d4>] __kernfs_create_file+0x114/0x2a0 fs/kernfs/file.c:954
>  [<ffffffff819e68f5>] sysfs_add_file_mode_ns+0x225/0x520 fs/sysfs/file.c:305
>  [<     inline     >] create_files fs/sysfs/group.c:64
>  [<ffffffff819e8a89>] internal_create_group+0x239/0x8f0 fs/sysfs/group.c:134
>  [<ffffffff819e915f>] sysfs_create_group+0x1f/0x30 fs/sysfs/group.c:156
>  [<ffffffff8323de24>] vhci_start+0x5b4/0x7a0 drivers/usb/usbip/vhci_hcd.c:978
>  [<ffffffff82c907ca>] usb_add_hcd+0x8da/0x1c60 drivers/usb/core/hcd.c:2867
>  [<ffffffff8323bc57>] vhci_hcd_probe+0x97/0x130
> drivers/usb/usbip/vhci_hcd.c:1103
>  ---
>  ---
> ---[ end trace c33c7b202cf3aac8 ]---
> 
> Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
> Reported-by: Andrey Konovalov <andreyknvl@google.com>

Here is the fix. Fixed the warning I reproduced on my system.
Let me know if it works for you.

thanks,
-- Shuah

> ---
>  drivers/usb/usbip/vhci_sysfs.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/usb/usbip/vhci_sysfs.c b/drivers/usb/usbip/vhci_sysfs.c
> index c404017..b96e5b1 100644
> --- a/drivers/usb/usbip/vhci_sysfs.c
> +++ b/drivers/usb/usbip/vhci_sysfs.c
> @@ -361,6 +361,7 @@ static void set_status_attr(int id)
>  	status->attr.attr.name = status->name;
>  	status->attr.attr.mode = S_IRUGO;
>  	status->attr.show = status_show;
> +	sysfs_attr_init(&status->attr.attr);
>  }
>  
>  static int init_status_attrs(void)
>