linux-kernel - Re: [REGRESSION] x86/entry: TIF_SINGLESTEP handling is still broken

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Date:   Sun, 31 Jan 2021 12:10:48 -0800
From:   Linus Torvalds <torvalds@...ux-foundation.org>
To:     Yuxuan Shui <yshuiv7@...il.com>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Andy Lutomirski <luto@...nel.org>,
        Gabriel Krisman Bertazi <krisman@...labora.com>,
        open list <linux-kernel@...r.kernel.org>,
        "Robert O'Callahan" <rocallahan@...il.com>,
        Kyle Huey <me@...ehuey.com>
Subject: Re: [REGRESSION] x86/entry: TIF_SINGLESTEP handling is still broken

On Sun, Jan 31, 2021 at 10:54 AM Yuxuan Shui <yshuiv7@...il.com> wrote:
>
> But renaming the definition in x86 is not enough, as TIF_SINGLESTEP is
> set in current_thread_info()->flags, and the same commit has removed the
> code that checks those flags. We have to also migrate TIF_SINGLESTEP from
> thread info flags to syscall work flags, to make the whole thing work again.

Ok, so I now have the first fix merged, but what's the next step here?

As you say, the x86 ARCH_SYSCALL_EXIT_WORK is now entirely unused.

It's called ARCH_SYSCALL_WORK_EXIT these days, but that's for the
SYSCALL_WORK_SYSCALL_xyz flags, not for the TIF_xyz ones.

Revert? Or does somebody have a fix patch?

            Linus