From: Jan Kara <jack@suse.cz>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: kbuild@01.org, Jan Kara <jack@suse.cz>,
Linux Memory Management List <linux-mm@kvack.org>
Subject: Re: [mmotm:master 64/350] fs/ocfs2/dlmglue.c:3184 ocfs2_mark_lockres_freeing() error: double lock 'irqsave:flags'
Date: Wed, 26 Feb 2014 12:02:09 +0100 [thread overview]
Message-ID: <20140226110209.GB6989@quack.suse.cz> (raw)
In-Reply-To: <20140226104835.GY26776@mwanda>
Hi,
On Wed 26-02-14 13:48:35, Dan Carpenter wrote:
> [ False positive, this is not a bug, it's just that the second IRQ save
> is unnecessary ].
> FYI, there are new smatch warnings show up in
>
> tree: git://git.cmpxchg.org/linux-mmotm.git master
> head: a6a1126d3535f0bd8d7c56810061541a4f5595af
> commit: c8acdd9e9cf2dd5a5f62034dfaf93c721b3f405d [64/350] ocfs2: avoid blocking in ocfs2_mark_lockres_freeing() in downconvert thread
>
> fs/ocfs2/dlmglue.c:3184 ocfs2_mark_lockres_freeing() error: double lock 'irqsave:flags'
> fs/ocfs2/dlmglue.c:3204 ocfs2_mark_lockres_freeing() error: double unlock 'irqsave:flags'
Yeah. I actually have an updated version of a patch which doesn't have
these two nested irqsafe calls. I'll send it to Andrew. Thanks for letting
me know.
Honza
> git remote add mmotm git://git.cmpxchg.org/linux-mmotm.git
> git remote update mmotm
> git checkout c8acdd9e9cf2dd5a5f62034dfaf93c721b3f405d
> vim +3184 fs/ocfs2/dlmglue.c
>
> c8acdd9e Jan Kara 2014-02-25 3178 * ocfs2_clear_inode()
> c8acdd9e Jan Kara 2014-02-25 3179 * ocfs2_mark_lockres_freeing()
> c8acdd9e Jan Kara 2014-02-25 3180 * ... blocks waiting for OCFS2_LOCK_QUEUED
> c8acdd9e Jan Kara 2014-02-25 3181 * since we are the downconvert thread which
> c8acdd9e Jan Kara 2014-02-25 3182 * should clear the flag.
> c8acdd9e Jan Kara 2014-02-25 3183 */
> c8acdd9e Jan Kara 2014-02-25 @3184 spin_lock_irqsave(&osb->dc_task_lock, flags);
> c8acdd9e Jan Kara 2014-02-25 3185 list_del_init(&lockres->l_blocked_list);
> c8acdd9e Jan Kara 2014-02-25 3186 osb->blocked_lock_count--;
> c8acdd9e Jan Kara 2014-02-25 3187 spin_unlock_irqrestore(&osb->dc_task_lock, flags);
> c8acdd9e Jan Kara 2014-02-25 3188 lockres_clear_flags(lockres, OCFS2_LOCK_QUEUED);
> c8acdd9e Jan Kara 2014-02-25 3189 goto out_unlock;
> c8acdd9e Jan Kara 2014-02-25 3190 }
> ccd979bd Mark Fasheh 2005-12-15 3191 while (lockres->l_flags & OCFS2_LOCK_QUEUED) {
> ccd979bd Mark Fasheh 2005-12-15 3192 lockres_add_mask_waiter(lockres, &mw, OCFS2_LOCK_QUEUED, 0);
> ccd979bd Mark Fasheh 2005-12-15 3193 spin_unlock_irqrestore(&lockres->l_lock, flags);
> ccd979bd Mark Fasheh 2005-12-15 3194
> ccd979bd Mark Fasheh 2005-12-15 3195 mlog(0, "Waiting on lockres %s\n", lockres->l_name);
> ccd979bd Mark Fasheh 2005-12-15 3196
> ccd979bd Mark Fasheh 2005-12-15 3197 status = ocfs2_wait_for_mask(&mw);
> ccd979bd Mark Fasheh 2005-12-15 3198 if (status)
> ccd979bd Mark Fasheh 2005-12-15 3199 mlog_errno(status);
> ccd979bd Mark Fasheh 2005-12-15 3200
> ccd979bd Mark Fasheh 2005-12-15 3201 spin_lock_irqsave(&lockres->l_lock, flags);
> ccd979bd Mark Fasheh 2005-12-15 3202 }
> c8acdd9e Jan Kara 2014-02-25 3203 out_unlock:
> ccd979bd Mark Fasheh 2005-12-15 @3204 spin_unlock_irqrestore(&lockres->l_lock, flags);
> ccd979bd Mark Fasheh 2005-12-15 3205 }
> ccd979bd Mark Fasheh 2005-12-15 3206
> d680efe9 Mark Fasheh 2006-09-08 3207 void ocfs2_simple_drop_lockres(struct ocfs2_super *osb,
>
> ---
> 0-DAY kernel build testing backend Open Source Technology Center
> http://lists.01.org/mailman/listinfo/kbuild Intel Corporation
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
prev parent reply other threads:[~2014-02-26 11:02 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-26 10:48 [mmotm:master 64/350] fs/ocfs2/dlmglue.c:3184 ocfs2_mark_lockres_freeing() error: double lock 'irqsave:flags' Dan Carpenter
2014-02-26 11:02 ` Jan Kara [this message]
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=20140226110209.GB6989@quack.suse.cz \
--to=jack@suse.cz \
--cc=dan.carpenter@oracle.com \
--cc=kbuild@01.org \
--cc=linux-mm@kvack.org \
/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).