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

[Andy Lutomirski]

On Thu, Oct 8, 2015 at 1:59 AM, Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> 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?

No, because while LOCKDEP_SYS_EXIT only happens in the fast path,
lockdep_sys_exit (lowercase) will get called in the other cases.

--Andy
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