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From: Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
To: Paul Turner <commonly-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
	Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>,
	Andrew Hunter <ahh-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
	Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>,
	Andi Kleen <andi-Vw/NltI1exuRpAAqCnN02g@public.gmane.org>,
	Mathieu Desnoyers
	<mathieu.desnoyers-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>,
	Dave Watson <davejwatson-b10kYP2dOMg@public.gmane.org>,
	"Paul E. McKenney"
	<paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
Cc: linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Josh Triplett <josh-iaAMLnmF4UmaiuxdJuQwMA@public.gmane.org>,
	Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Chris Lameter <cl-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org>,
	Linus Torvalds
	<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>
Subject: Re: [RFC PATCH v2 1/3] restartable sequences: user-space per-cpu critical sections
Date: Thu, 19 Nov 2015 17:38:10 +0100	[thread overview]
Message-ID: <1447951090.2765.9.camel@sipsolutions.net> (raw)
In-Reply-To: <20151027235653.16059.8933.stgit-G8L5E6GV2z5XSTzz+wBt03oUN1GumTyQ7j82oEJ37pA@public.gmane.org>

On Tue, 2015-10-27 at 16:56 -0700, Paul Turner wrote:
> 
> + *  flags is currently unused.
> + */
> +SYSCALL_DEFINE3(restartable_sequences,
> +> 	> 	> int, flags, long, event_and_cpu, long, post_commit_instr_addr)
	
> +{
> +	return rseq_configure_current((__user u64 *)event_and_cpu,
> +				      (__user void *)post_commit_instr_addr);

It seems that, for forward compatibility and actually usefulness of the
'flags' argument, you need to reject the syscall if it's passed non-
zero right now. Otherwise applications can (inadvertedly) pass garbage
and you'll not be able to use it in the future.

johannes

  parent reply	other threads:[~2015-11-19 16:38 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-10-27 23:56 [RFC PATCH 0/3] restartable sequences v2: fast user-space percpu critical sections Paul Turner
2015-10-27 23:56 ` [RFC PATCH v2 1/3] restartable sequences: user-space per-cpu " Paul Turner
     [not found]   ` <20151027235653.16059.8933.stgit-G8L5E6GV2z5XSTzz+wBt03oUN1GumTyQ7j82oEJ37pA@public.gmane.org>
2015-11-19 16:38     ` Johannes Berg [this message]
2015-12-11 12:56     ` Mathieu Desnoyers
2015-10-27 23:57 ` [RFC PATCH v2 2/3] restartable sequences: x86 ABI Paul Turner
     [not found]   ` <20151027235705.16059.63268.stgit-G8L5E6GV2z5XSTzz+wBt03oUN1GumTyQ7j82oEJ37pA@public.gmane.org>
2015-10-28  5:03     ` Peter Zijlstra
     [not found]       ` <20151028050314.GC11242-IIpfhp3q70xmmu7s1q4rt2t3HXsI98Cx0E9HWUfgJXw@public.gmane.org>
2015-10-28  5:19         ` Paul Turner
2015-12-11 13:30     ` Mathieu Desnoyers
2015-10-27 23:57 ` [RFC PATCH v2 3/3] restartable sequences: basic self-tests Paul Turner
     [not found]   ` <20151027235716.16059.47610.stgit-G8L5E6GV2z5XSTzz+wBt03oUN1GumTyQ7j82oEJ37pA@public.gmane.org>
2016-04-05 20:33     ` Mathieu Desnoyers
     [not found]       ` <1276514010.46061.1459888406999.JavaMail.zimbra-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>
2016-04-06  7:43         ` Peter Zijlstra
     [not found]           ` <20160406074309.GE3430-ndre7Fmf5hadTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
2016-04-06 13:39             ` Mathieu Desnoyers
     [not found]               ` <528054829.46502.1459949962537.JavaMail.zimbra-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>
2016-04-06 19:25                 ` Peter Zijlstra
     [not found] ` <20151027235635.16059.11630.stgit-G8L5E6GV2z5XSTzz+wBt03oUN1GumTyQ7j82oEJ37pA@public.gmane.org>
2015-10-28 14:44   ` [RFC PATCH 0/3] restartable sequences v2: fast user-space percpu critical sections Dave Watson
2015-12-11 12:05   ` Mathieu Desnoyers
     [not found]     ` <1070636085.232143.1449835536723.JavaMail.zimbra-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>
2015-12-11 13:39       ` Mathieu Desnoyers
2016-04-06 15:56 ` Andy Lutomirski
2016-04-07 12:02   ` Peter Zijlstra
     [not found]     ` <20160407120254.GY3448-ndre7Fmf5hadTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
2016-04-07 14:35       ` Andy Lutomirski
     [not found]         ` <CALCETrV0vcYcnBrs0axykJD=_BM28wKWVMG6bMzK8zh8R3m5fg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-04-07 15:24           ` Peter Zijlstra
     [not found]             ` <20160407152432.GZ3448-ndre7Fmf5hadTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
2016-04-07 15:39               ` Peter Zijlstra
2016-04-07 15:44               ` Andy Lutomirski
     [not found]                 ` <CALCETrU5ZL6Jajc=9up-j86vY_Xtt-gTFjdQE0sB0d=d-CJZ6A-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-04-07 15:53                   ` Peter Zijlstra
     [not found]                     ` <20160407155312.GA3448-ndre7Fmf5hadTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
2016-04-07 16:43                       ` Andy Lutomirski
     [not found]                         ` <CALCETrVGo1Di3qamxx1NAFUSN_o=-HnYRDpeVp7zrQEBwe5u-g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-04-07 20:11                           ` Peter Zijlstra
     [not found]                             ` <20160407201156.GC3448-ndre7Fmf5hadTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
2016-04-07 22:05                               ` Andy Lutomirski
     [not found]                                 ` <CALCETrXVReuuGGKW6EOV7tFFaK9RbwWxYvKdpUdvU=MpDaOtsQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-04-08  1:11                                   ` Mathieu Desnoyers
2016-04-08  1:21                                     ` Andy Lutomirski
2016-04-08  2:05                                       ` Mathieu Desnoyers
2016-04-08 17:46                                         ` Mathieu Desnoyers
     [not found]                                           ` <65466698.51122.1460137589499.JavaMail.zimbra-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>
2016-04-08 21:16                                             ` Andy Lutomirski
2016-04-08 21:25                                             ` Linus Torvalds
     [not found]                                               ` <CA+55aFwqJmTy+Nz0k9N_2zsms51meTFMdvYYW5VHdiOq8Jjr7Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2016-04-10 14:07                                                 ` Mathieu Desnoyers
2016-04-08 11:02                                   ` Peter Zijlstra
     [not found]                                     ` <20160408110232.GP3448-ndre7Fmf5hadTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
2016-04-08 15:57                                       ` Andy Lutomirski
2016-04-08  6:41                           ` Peter Zijlstra
     [not found]                             ` <20160408064136.GJ3448-ndre7Fmf5hadTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
2016-04-08 15:58                               ` Andy Lutomirski
2016-04-11 21:55                           ` Mathieu Desnoyers

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