From: Oleg Nesterov <oleg@redhat.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Kees Cook <keescook@chromium.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@alien8.de>,
Ingo Molnar <mingo@kernel.org>,
Jan Kratochvil <jan.kratochvil@redhat.com>,
Pedro Alves <palves@redhat.com>, Peter Anvin <hpa@zytor.com>,
Thomas Gleixner <tglx@linutronix.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
the arch/x86 maintainers <x86@kernel.org>
Subject: Re: [PATCH] ptrace/x86: introduce TS_COMPAT_RESTART to fix get_nr_restart_syscall()
Date: Fri, 29 Nov 2019 18:32:13 +0100 [thread overview]
Message-ID: <20191129173213.GB3992@redhat.com> (raw)
In-Reply-To: <EB7AF2AE-6CA3-4395-AA37-BF92EE308A42@amacapital.net>
On 11/28, Andy Lutomirski wrote:
>
> I think this doesn’t work for x32.
Why? get_nr_restart_syscall() can still rely on the "orig_ax & __X32_SYSCALL_BIT"
check, debugger should restore regs->orig_ax correctly.
> Let’s either save the result of syscall_get_arch()
We can save the result of syscall_get_arch(), but it doesn't distinguish
x32/x86_64 tasks, so it doesn't really differ from TS_COMPAT.
> or just actually calculate and save the restart_syscall nr here.
sure, we we can do this.
> Before we commit to this, Kees, do you think we can manage to just renumber
> restart_syscall()? That’s a much better solution if we can pull it off.
Agreed.
Oleg.
next prev parent reply other threads:[~2019-11-29 17:32 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-26 11:06 [PATCH] ptrace/x86: introduce TS_COMPAT_RESTART to fix get_nr_restart_syscall() Oleg Nesterov
2019-11-26 11:07 ` Oleg Nesterov
2019-11-27 4:04 ` Linus Torvalds
2019-11-27 5:46 ` Andy Lutomirski
2019-11-27 17:06 ` Oleg Nesterov
2019-11-27 17:02 ` Oleg Nesterov
2019-11-27 17:21 ` Linus Torvalds
2019-11-28 15:36 ` Oleg Nesterov
2019-11-28 19:24 ` Linus Torvalds
2019-11-28 21:13 ` Andy Lutomirski
2019-11-29 17:32 ` Oleg Nesterov [this message]
2019-11-29 18:19 ` Andy Lutomirski
2019-11-29 17:21 ` Oleg Nesterov
2019-12-03 14:12 ` [PATCH v2 0/4] x86: " Oleg Nesterov
2019-12-03 14:13 ` [PATCH v2 1/4] introduce set_restart_fn() and arch_set_restart_data() Oleg Nesterov
2019-12-04 15:09 ` Oleg Nesterov
2019-12-04 15:09 ` [PATCH v3 " Oleg Nesterov
2019-12-03 14:13 ` [PATCH v2 2/4] x86: mv TS_COMPAT from asm/processor.h to asm/thread_info.h Oleg Nesterov
2019-12-03 14:13 ` [PATCH v2 3/4] x86: introduce TS_COMPAT_RESTART to fix get_nr_restart_syscall() Oleg Nesterov
2019-12-03 14:14 ` [PATCH v2 4/4] x86: introduce restart_block->arch_data to kill TS_COMPAT_RESTART Oleg Nesterov
2019-12-18 15:19 ` [PATCH v2 0/4] x86: fix get_nr_restart_syscall() Oleg Nesterov
2019-12-18 20:02 ` Linus Torvalds
2019-12-19 2:48 ` Andy Lutomirski
2020-02-17 15:54 ` Thomas Gleixner
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