Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933826AbcLHCvR (ORCPT ); Wed, 7 Dec 2016 21:51:17 -0500 Received: from ec2-52-27-115-49.us-west-2.compute.amazonaws.com ([52.27.115.49]:60461 "EHLO osg.samsung.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932532AbcLHCvP (ORCPT ); Wed, 7 Dec 2016 21:51:15 -0500 Subject: Re: [PATCH] usbip: fix warning in vhci_hcd_probe/lockdep_init_map To: fx IWATA NOBUO , Andrey Konovalov References: <20161205195638.7005-1-shuahkh@osg.samsung.com> <4a3b7e4f-6b5c-d9e8-f26c-1286d4e1f630@osg.samsung.com> Cc: Greg Kroah-Hartman , Valentina Manea , Shuah Khan , "linux-usb@vger.kernel.org" , LKML , Shuah Khan , Shuah Khan From: Shuah Khan Message-ID: <8167945c-36b5-1797-b220-54428d4c7869@osg.samsung.com> Date: Wed, 7 Dec 2016 19:51:11 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4574 Lines: 124 Hi Nobuo.iwata, I noticed that in many places sysfs_attr_init() is called before populating the fields such as name etc. However, I don't think the order matters. sysfs_attr_init() doesn't depend on name or any other fields being set: #define sysfs_attr_init(attr) \ do { \ static struct lock_class_key __key; \ \ (attr)->key = &__key; \ } while (0) Are you concerned about something else? thanks, -- Shuah On 12/07/2016 07:15 PM, fx IWATA NOBUO wrote: > Dear Shuah, > > I'm afraid there's one thing I have concerned. > > I think it's better to move sysfs_attr_init() before > status->attr.attr.name = status->name; > > Best Regards, > > nobuo.iwata > // >> -----Original Message----- >> From: linux-usb-owner@vger.kernel.org >> [mailto:linux-usb-owner@vger.kernel.org] On Behalf Of Andrey Konovalov >> Sent: Tuesday, December 06, 2016 9:07 PM >> To: Shuah Khan >> Cc: Greg Kroah-Hartman; Valentina Manea; Shuah Khan; >> linux-usb@vger.kernel.org; LKML >> Subject: Re: [PATCH] usbip: fix warning in vhci_hcd_probe/lockdep_init_map >> >> On Mon, Dec 5, 2016 at 9:00 PM, Shuah Khan wrote: >>> 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 >>>> [] dump_stack+0x292/0x398 lib/dump_stack.c:51 >>>> [] __warn+0x19f/0x1e0 kernel/panic.c:550 >>>> [] warn_slowpath_fmt+0xc5/0x110 kernel/panic.c:565 >>>> [] lockdep_init_map+0x60c/0x770 >>>> kernel/locking/lockdep.c:3131 [] >>>> __kernfs_create_file+0x114/0x2a0 fs/kernfs/file.c:954 >> [] sysfs_add_file_mode_ns+0x225/0x520 >> fs/sysfs/file.c:305 >>>> [< inline >] create_files fs/sysfs/group.c:64 >>>> [] internal_create_group+0x239/0x8f0 >>>> fs/sysfs/group.c:134 [] >>>> sysfs_create_group+0x1f/0x30 fs/sysfs/group.c:156 >>>> [] vhci_start+0x5b4/0x7a0 >>>> drivers/usb/usbip/vhci_hcd.c:978 [] >>>> usb_add_hcd+0x8da/0x1c60 drivers/usb/core/hcd.c:2867 >>>> [] vhci_hcd_probe+0x97/0x130 >>>> drivers/usb/usbip/vhci_hcd.c:1103 >>>> --- >>>> --- >>>> ---[ end trace c33c7b202cf3aac8 ]--- >>>> >>>> Signed-off-by: Shuah Khan >>>> Reported-by: Andrey Konovalov >>> >>> Here is the fix. Fixed the warning I reproduced on my system. >>> Let me know if it works for you. >> >> Hi Shuah, >> >> This fixes the warning I've been seeing. >> >> Thanks! >> >>> >>> 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) >>>> >>> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-usb" in >> the body of a message to majordomo@vger.kernel.org More majordomo info at >> http://vger.kernel.org/majordomo-info.html