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From: Greg KH <greg@kroah.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	mingo@kernel.org, mgorman@suse.de, juri.lelli@redhat.com,
	vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com,
	joshdon@google.com, valentin.schneider@arm.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 6/9] debugfs: Implement debugfs_create_str()
Date: Sat, 27 Mar 2021 11:41:36 +0100	[thread overview]
Message-ID: <YF8L4BMSMeuIq2JS@kroah.com> (raw)
In-Reply-To: <20210326151912.GL4746@worktop.programming.kicks-ass.net>

On Fri, Mar 26, 2021 at 04:19:12PM +0100, Peter Zijlstra wrote:
> On Fri, Mar 26, 2021 at 03:58:37PM +0100, Rasmus Villemoes wrote:
> > >   kmalloc(len + 2, ...);
> > 
> > No, because nul-terminating the stuff you pass to
> > simple_read_from_buffer is pointless cargo-culting. Yeah, read_file_bool
> > does it, but that's just bogus.
> 
> Urgh, feel yuck to not have it zero terminated, but if you feel strongly
> about it I suppose I can make it go away.
> 
> > > 	len = strscpy(copy, str, len);
> > > 	if (len < 0)
> > > 		return len;
> > 
> > To what end? The only way that could possibly return -EFOO is if the
> > nul-terminator in str vanished between the strlen() and here, and in
> > that case you have bigger problems.
> 
> There are strings in the kernel which we rewrite in most ugly ways,
> task_struct::comm comes to mind. Best be paranoid.
> 
> > > Copy-pasta from debugfs_*_bool(). This thing seems to export everything
> > > and I figured I'd go along with that.
> > 
> > I thought the convention was not to export anything until the kernel
> > itself had a (modular) user.
> 
> That's generally how I feel too. But this really isn't my subsystem so I
> more or less try to mimmick what I see done there.

I'll take some time next week and go through and remove any exports in
debugfs that are not actually needed for exports as it's been a while
since I last looked...

But that should not affect this change, it's fine to me as-is.

thanks,

greg k-h

  reply	other threads:[~2021-03-27 10:41 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26 10:33 [PATCH 0/9] sched: Clean up SCHED_DEBUG Peter Zijlstra
2021-03-26 10:33 ` [PATCH 1/9] sched/numa: Allow runtime enabling/disabling of NUMA balance without SCHED_DEBUG Peter Zijlstra
2021-03-26 10:33 ` [PATCH 2/9] sched: Remove sched_schedstats sysctl out from under SCHED_DEBUG Peter Zijlstra
2021-03-26 10:33 ` [PATCH 3/9] sched: Dont make LATENCYTOP select SCHED_DEBUG Peter Zijlstra
2021-03-26 10:33 ` [PATCH 4/9] sched: Move SCHED_DEBUG to debugfs Peter Zijlstra
2021-03-26 11:06   ` Greg KH
2021-04-07 10:46   ` Valentin Schneider
2021-04-07 12:26     ` Peter Zijlstra
2021-04-07 12:57       ` Valentin Schneider
2021-03-26 10:33 ` [PATCH 5/9] sched,preempt: Move preempt_dynamic to debug.c Peter Zijlstra
2021-03-26 10:33 ` [PATCH 6/9] debugfs: Implement debugfs_create_str() Peter Zijlstra
2021-03-26 11:05   ` Greg KH
2021-03-26 11:18     ` Peter Zijlstra
2021-03-26 11:30       ` Greg KH
2021-03-26 11:38         ` [PATCH v2 " Peter Zijlstra
2021-03-26 12:18           ` Greg KH
2021-03-26 12:53           ` Rasmus Villemoes
2021-03-26 12:57             ` Greg KH
2021-03-26 13:10               ` Rasmus Villemoes
2021-03-26 14:12                 ` Peter Zijlstra
2021-03-26 14:19                   ` Greg KH
2021-03-26 14:22             ` Peter Zijlstra
2021-03-26 14:58               ` Rasmus Villemoes
2021-03-26 15:19                 ` Peter Zijlstra
2021-03-27 10:41                   ` Greg KH [this message]
2021-03-26 14:50   ` [PATCH v3 " Peter Zijlstra
2021-03-27 10:42     ` Greg KH
2021-03-27 22:24   ` [PATCH " Al Viro
2021-03-28  0:33     ` Steven Rostedt
2021-03-26 10:33 ` [PATCH 7/9] sched,debug: Convert sysctl sched_domains to debugfs Peter Zijlstra
2021-03-26 13:11   ` Dietmar Eggemann
2021-04-07 10:46   ` Valentin Schneider
2021-04-07 12:18     ` Peter Zijlstra
2021-03-26 10:34 ` [PATCH 8/9] sched: Move /proc/sched_debug " Peter Zijlstra
2021-03-26 11:05   ` Greg KH
2021-03-26 10:34 ` [PATCH 9/9] sched,fair: Alternative sched_slice() Peter Zijlstra
2021-03-26 12:08   ` Dietmar Eggemann
2021-03-26 14:07     ` Peter Zijlstra
2021-03-26 15:37   ` Vincent Guittot
2021-03-26 18:30     ` Peter Zijlstra
2021-04-12 10:14 [PATCH v2 0/9] sched: Clean up SCHED_DEBUG Peter Zijlstra
2021-04-12 10:14 ` [PATCH v2 6/9] debugfs: Implement debugfs_create_str() Peter Zijlstra

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