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From: Thomas Gleixner <tglx@linutronix.de>
To: Joshua Hudson <joshudson@gmail.com>,
	Ammar Faizi <ammarfaizi2@gnuweeb.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	x86-ml <x86@kernel.org>
Subject: Re: System Call trashing registers
Date: Fri, 01 Sep 2023 20:49:09 +0200	[thread overview]
Message-ID: <87a5u54tlm.ffs@tglx> (raw)
In-Reply-To: <CA+jjjYSMq-hKx5XsMDf=+n4wfAr6Btt7x8gpG5kdRRrzr6YK2Q@mail.gmail.com>

On Fri, Sep 01 2023 at 10:38, Joshua Hudson wrote:
> On Fri, Sep 1, 2023 at 9:24 AM Ammar Faizi <ammarfaizi2@gnuweeb.org> wrote:
>
> Correction: it's been fixed again. Sorry about that.

When exactly was it broken? Which kernel version?

The save/restore mechanism is not changing every other day.

> I know the asmutils tools have been broken for a decade, but they're
> working now.
>
> What would happen is system calls that take arguments in ecx and edx would find
> ecx and edx trashed, but only a few calls actually did this, the
> primary offender
> being open(). The best regression test seems to be hexdump from
> asmutils because the
> corruption would reliably crash the binary. sched_yeild was never an
> affected syscall.

It does absolutely not matter which syscall is used. The save/restore
mechanism is identical for all syscalls.

Thanks,

        tglx



      reply	other threads:[~2023-09-01 18:49 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-08-24 16:15 System Call trashing registers Joshua Hudson
2023-08-28 15:06 ` Pavel Machek
2023-08-28 16:41   ` Joshua Hudson
2023-08-28 17:06 ` David Laight
2023-08-28 17:11   ` Joshua Hudson
2023-09-01 16:24 ` Ammar Faizi
2023-09-01 17:03   ` Thomas Gleixner
2023-09-01 17:38   ` Joshua Hudson
2023-09-01 18:49     ` Thomas Gleixner [this message]

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