linux-kernel - Re: [tip:x86/asm] x86/entry, locking/lockdep: Move lockdep_sys_exit() to prepare_exit_to

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Message-ID: <20151008085916.GG3604@twins.programming.kicks-ass.net>
Date:	Thu, 8 Oct 2015 10:59:16 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	luto@...nel.org, hpa@...or.com, bp@...en8.de, mingo@...nel.org,
	brgerst@...il.com, luto@...capital.net,
	torvalds@...ux-foundation.org, dvlasenk@...hat.com,
	linux-kernel@...r.kernel.org, tglx@...utronix.de
Cc:	linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/asm] x86/entry, locking/lockdep: Move
 lockdep_sys_exit() to prepare_exit_to_usermode()

On Wed, Oct 07, 2015 at 09:17:44AM -0700, tip-bot for Andy Lutomirski wrote:
> Commit-ID:  72f924783b8a87e4454516520ffb5f35e4930371
> Gitweb:     http://git.kernel.org/tip/72f924783b8a87e4454516520ffb5f35e4930371
> Author:     Andy Lutomirski <luto@...nel.org>
> AuthorDate: Mon, 5 Oct 2015 17:47:54 -0700
> Committer:  Ingo Molnar <mingo@...nel.org>
> CommitDate: Wed, 7 Oct 2015 11:34:07 +0200
> 
> x86/entry, locking/lockdep: Move lockdep_sys_exit() to prepare_exit_to_usermode()
> 
> Rather than worrying about exactly where LOCKDEP_SYS_EXIT should
> go in the asm code, add it to prepare_exit_from_usermode() and
> remove all of the asm calls that are followed by
> prepare_exit_to_usermode().
> 
> LOCKDEP_SYS_EXIT now appears only in the syscall fast paths.

Does that not pose a risk that something that always takes the slow path
(signals? tracing?) will leak a lock to userspace?
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