From: Matthew Wilcox <willy@infradead.org>
To: Dan Carpenter <dan.carpenter@oracle.com>
Cc: linux-fsdevel@vger.kernel.org, xiang@kernel.org,
linux-erofs@lists.ozlabs.org
Subject: Re: [bug report] staging: erofs: tidy up decompression frontend
Date: Thu, 14 Nov 2019 14:00:15 -0800 [thread overview]
Message-ID: <20191114220015.GA20752@bombadil.infradead.org> (raw)
In-Reply-To: <20191114190848.f6tlqpnybagez76g@kili.mountain>
On Thu, Nov 14, 2019 at 10:10:03PM +0300, Dan Carpenter wrote:
> fs/erofs/zdata.c:443 z_erofs_register_collection()
> error: double unlocked 'cl->lock' (orig line 439)
>
> fs/erofs/zdata.c
> 432 cl = z_erofs_primarycollection(pcl);
> 433 cl->pageofs = map->m_la & ~PAGE_MASK;
> 434
> 435 /*
> 436 * lock all primary followed works before visible to others
> 437 * and mutex_trylock *never* fails for a new pcluster.
> 438 */
> 439 mutex_trylock(&cl->lock);
> ^^^^^^^^^^^^^^^^^^^^^^^^
> 440
> 441 err = erofs_register_workgroup(inode->i_sb, &pcl->obj, 0);
> 442 if (err) {
> 443 mutex_unlock(&cl->lock);
> ^^^^^^^^^^^^^^^^^^^^^^^
> How can we unlock if we don't know that the trylock succeeded?
The comment says it'll always succeed. That said, this is an uncommon
pattern -- usually we just mutex_lock(). If there's a good reason to use
mutex_trylock() instead, then I'd prefer it to be guarded with a BUG_ON.
next prev parent reply other threads:[~2019-11-14 22:00 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-14 19:10 [bug report] staging: erofs: tidy up decompression frontend Dan Carpenter
2019-11-14 22:00 ` Matthew Wilcox [this message]
2019-11-15 0:45 ` Gao Xiang via Linux-erofs
2019-11-15 0:45 ` Gao Xiang
-- strict thread matches above, loose matches on Subject: below --
2019-08-27 9:03 Dan Carpenter
2019-08-27 9:36 ` Gao Xiang
2019-08-27 9:53 ` Dan Carpenter
2019-08-27 10:05 ` Gao Xiang
2019-08-27 10:42 ` Dan Carpenter
2019-08-27 10:46 ` Gao Xiang
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=20191114220015.GA20752@bombadil.infradead.org \
--to=willy@infradead.org \
--cc=dan.carpenter@oracle.com \
--cc=linux-erofs@lists.ozlabs.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=xiang@kernel.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).