linux-kernel - Re: [PATCH 1/2] Allow a kthread to declare that it calls task_work

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: <170172387681.7109.15402426750268670177@noble.neil.brown.name>
Date:   Tue, 05 Dec 2023 08:04:36 +1100
From:   "NeilBrown" <neilb@...e.de>
To:     "Matthew Wilcox" <willy@...radead.org>
Cc:     "Al Viro" <viro@...iv.linux.org.uk>,
        "Christian Brauner" <brauner@...nel.org>,
        "Jens Axboe" <axboe@...nel.dk>, "Oleg Nesterov" <oleg@...hat.com>,
        "Chuck Lever" <chuck.lever@...cle.com>,
        "Jeff Layton" <jlayton@...nel.org>,
        "Ingo Molnar" <mingo@...hat.com>,
        "Peter Zijlstra" <peterz@...radead.org>,
        "Juri Lelli" <juri.lelli@...hat.com>,
        "Vincent Guittot" <vincent.guittot@...aro.org>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-nfs@...r.kernel.org
Subject: Re: [PATCH 1/2] Allow a kthread to declare that it calls task_work_run()

On Mon, 04 Dec 2023, Matthew Wilcox wrote:
> On Mon, Dec 04, 2023 at 12:36:41PM +1100, NeilBrown wrote:
> > +++ b/fs/namespace.c
> > @@ -1328,7 +1328,7 @@ static void mntput_no_expire(struct mount *mnt)
> >  
> >  	if (likely(!(mnt->mnt.mnt_flags & MNT_INTERNAL))) {
> >  		struct task_struct *task = current;
> > -		if (likely(!(task->flags & PF_KTHREAD))) {
> > +		if (likely((task->flags & PF_RUNS_TASK_WORK))) {
> 
> You could lose one set of parens here ...
> 
> 		if (likely(task->flags & PF_RUNS_TASK_WORK)) {

Done.

> 
> >  #define PF_RANDOMIZE		0x00400000	/* Randomize virtual address space */
> > -#define PF__HOLE__00800000	0x00800000
> > +#define PF_RUNS_TASK_WORK	0x00800000	/* Will call task_work_run() periodically */
> 
> And you could lose "Will" here:
> 
> #define PF_RUNS_TASK_WORK    0x00800000      /* Calls task_work_run() periodically */

Better - thanks.


> 
> > diff --git a/kernel/task_work.c b/kernel/task_work.c
> > index 95a7e1b7f1da..aec19876e121 100644
> > --- a/kernel/task_work.c
> > +++ b/kernel/task_work.c
> > @@ -183,3 +183,4 @@ void task_work_run(void)
> >  		} while (work);
> >  	}
> >  }
> > +EXPORT_SYMBOL(task_work_run);
> 
> _GPL?

Justification?

Thanks,
NeilBrown