linux-kernel - Re: v4.2-rc dcache regression, probably 75a6f82a0d10

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: <alpine.LSU.2.11.1507312101380.13738@eggly.anvils>
Date:	Fri, 31 Jul 2015 21:20:26 -0700 (PDT)
From:	Hugh Dickins <hughd@...gle.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
cc:	Hugh Dickins <hughd@...gle.com>,
	"J. Bruce Fields" <bfields@...ldses.org>,
	Dominique Martinet <dominique.martinet@....fr>,
	Dominique Martinet <asmadeus@...ewreck.org>,
	David Howells <dhowells@...hat.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	linux-fsdevel <linux-fsdevel@...r.kernel.org>
Subject: Re: v4.2-rc dcache regression, probably 75a6f82a0d10

On Fri, 31 Jul 2015, Hugh Dickins wrote:
> On Fri, 31 Jul 2015, Linus Torvalds wrote:
> > 
> > So leave it running a while longer, but maybe it's 4bf46a272647 like
> > Dominique suspects. Although I don't see how that could trigger
> > anything either..
> 
> I restarted with a slightly different version of the load this
> morning, which has sometimes shown the issue more easily - I thought
> it better to restart with a variant than persist with a run that
> might have settled into a protected pattern.  We'll see what that
> shows later on.

It showed nothing useful to this discussion: after an hour and a half
it had hung on some almost-certainly-unrelated issue that I've never
seen before - looked as if a jbd2 transaction never completed, some
tasks waiting for that, some waiting for f_pos_lock held by those
(which I hit when I tried to tail the output log).  Worry about
that another time, if it ever shows up again.

I think I'll try reinstating Al's commit, and hacking out that change
of David's in dentry_iput() that worried me (though the "especially
problematic" remark in his change description suggests that it is
an intentional and necessary change to suit unionmount).  See how
that goes.

Hugh
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/