From: Bastien Philbert <bastienphilbert@gmail.com>
To: Julian Calaby <julian.calaby@gmail.com>
Cc: jejb@linux.vnet.ibm.com,
"Martin K. Petersen" <martin.petersen@oracle.com>,
linux-scsi <linux-scsi@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] csiostor: Fix backwards locking in the function __csio_unreg_rnode
Date: Wed, 6 Apr 2016 09:21:38 -0400 [thread overview]
Message-ID: <57050D62.3090802@gmail.com> (raw)
In-Reply-To: <CAGRGNgXXBZb91xgRfkU_xtAF4rmCFbDFuxq8jRmQzJXU2wHb7Q@mail.gmail.com>
On 2016-04-06 03:48 AM, Julian Calaby wrote:
> Hi Bastien,
>
> On Wed, Apr 6, 2016 at 7:19 AM, Bastien Philbert
> <bastienphilbert@gmail.com> wrote:
>> This fixes backwards locking in the function __csio_unreg_rnode to
>> properly lock before the call to the function csio_unreg_rnode and
>> not unlock with spin_unlock_irq as this would not allow the proper
>> protection for concurrent access on the shared csio_hw structure
>> pointer hw. In addition switch the locking after the critical region
>> function call to properly unlock instead with spin_unlock_irq on
>>
>> Signed-off-by: Bastien Philbert <bastienphilbert@gmail.com>
>> ---
>> drivers/scsi/csiostor/csio_rnode.c | 4 ++--
>> 1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/scsi/csiostor/csio_rnode.c b/drivers/scsi/csiostor/csio_rnode.c
>> index e9c3b04..029a09e 100644
>> --- a/drivers/scsi/csiostor/csio_rnode.c
>> +++ b/drivers/scsi/csiostor/csio_rnode.c
>> @@ -580,9 +580,9 @@ __csio_unreg_rnode(struct csio_rnode *rn)
>> ln->last_scan_ntgts--;
>> }
>>
>> - spin_unlock_irq(&hw->lock);
>> - csio_unreg_rnode(rn);
>> spin_lock_irq(&hw->lock);
>> + csio_unreg_rnode(rn);
>> + spin_unlock_irq(&hw->lock);
>
> Are you _certain_ this is correct? This construct usually appears when
> a function has a particular lock held, then needs to unlock it to call
> some other function. Are you _certain_ that this isn't the case?
>
> Thanks,
>
Yes I am pretty certain this is correct. I checked the paths that called this function
and it was weired that none of them gradded the spinlock before hand.
Cheers,
Bastien
next prev parent reply other threads:[~2016-04-06 13:21 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-05 21:19 [PATCH] csiostor: Fix backwards locking in the function __csio_unreg_rnode Bastien Philbert
2016-04-06 7:48 ` Julian Calaby
2016-04-06 13:21 ` Bastien Philbert [this message]
2016-04-06 13:38 ` James Bottomley
2016-04-06 14:11 ` Bastien Philbert
2016-04-06 14:24 ` James Bottomley
2016-04-06 14:36 ` Bastien Philbert
2016-04-06 17:14 ` James Bottomley
2016-04-06 17:23 ` Bastien Philbert
2016-04-06 17:28 ` James Bottomley
2016-04-06 17:35 ` Bastien Philbert
2016-04-06 18:41 ` Greg KH
2016-04-06 19:34 ` Theodore Ts'o
[not found] <1441300143-1143-1-git-send-email-xerofoify@gmail.com>
2015-09-04 22:44 ` [PATCH] csiostor:Fix " Anish Bhatt
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=57050D62.3090802@gmail.com \
--to=bastienphilbert@gmail.com \
--cc=jejb@linux.vnet.ibm.com \
--cc=julian.calaby@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=martin.petersen@oracle.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).