Re: [tip:x86/asm] x86/entry, locking/lockdep: Move lockdep_sys_exit() to prepare_exit_to_usermode()

From: Peter Zijlstra
Date: Thu Oct 08 2015 - 04:59:36 EST


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@xxxxxxxxxx>
> AuthorDate: Mon, 5 Oct 2015 17:47:54 -0700
> Committer: Ingo Molnar <mingo@xxxxxxxxxx>
> 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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