linux-kernel - Re: [PATCH] f2fs: fix ref of discard command

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20170614142648.GA74571@jaegeuk-macbookpro.roam.corp.google.com>
Date:   Wed, 14 Jun 2017 07:26:48 -0700
From:   Jaegeuk Kim <jaegeuk@...nel.org>
To:     Chao Yu <yuchao0@...wei.com>
Cc:     linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-f2fs-devel@...ts.sourceforge.net
Subject: Re: [PATCH] f2fs: fix ref of discard command

On 06/12, Chao Yu wrote:
> Hi Jaegeuk,
> 
> On 2017/6/12 11:04, Jaegeuk Kim wrote:
> > This patch resolves kernel panic for xfstests/081, caused by recent f2fs_bug_on
> > 
> >   f2fs: add f2fs_bug_on in __remove_discard_cmd
> > 
> > Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
> > ---
> >  fs/f2fs/segment.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
> > index 86a0c1095939..a6d77388a806 100644
> > --- a/fs/f2fs/segment.c
> > +++ b/fs/f2fs/segment.c
> > @@ -1025,6 +1025,8 @@ static void __wait_discard_cmd(struct f2fs_sb_info *sbi, bool wait_cond)
> >  	list_for_each_entry_safe(dc, tmp, wait_list, list) {
> >  		if (!wait_cond || (dc->state == D_DONE && !dc->ref)) {
> >  			wait_for_completion_io(&dc->wait);
> > +			if (dc->state == D_DONE && dc->ref)
> > +				dc->ref--;
> 
> Should set dc->ref to 0 to avoid panic once we add other referrers?

Sorry, could you please explain this in more detail?

Thanks,

> 
> Thanks,
> 
> >  			__remove_discard_cmd(sbi, dc);
> >  		} else {
> >  			dc->ref++;
> >