From: Oleg Nesterov <oleg@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Denys Vlasenko <dvlasenk@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Jan Kratochvil <jan.kratochvil@redhat.com>,
Pedro Alves <palves@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
the arch/x86 maintainers <x86@kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: syscall_get_error() && TS_ checks
Date: Wed, 29 Mar 2017 20:50:41 +0200 [thread overview]
Message-ID: <20170329185041.GA24806@redhat.com> (raw)
In-Reply-To: <CA+55aFx_K58D10-J81PgDZnNcZATMDVL2k_8WJjAfb_EFiAsKw@mail.gmail.com>
On 03/29, Linus Torvalds wrote:
>
> That said, I'm not sure why you want to change this in the first
> place? I think the current syscall_get_error() - with explicit compat
> handling and all - is fine.
To simplify this logic. To kill TS_I386_REGS_POKED (which doesn't really
work and can't) and to remove the subtle dependency on TS_COMPAT in ret-
with-signal paths.
Again, afaics we only need these compat checks because regs->ax could be
changed by 32-bit debugger without sign-extension. And TS_I386_REGS_POKED
means that if TS_COMPAT is not set, then the debugger should have also
changed regs->orig_ax. This mostly works, but imo too fragile.
Currently we have the same check in get_nr_restart_syscall() but it is
even more broken (see the patch/changelog), so it should go away and in
this case it would be nice to avoid these checks in do_signal() path too.
Oleg.
next prev parent reply other threads:[~2017-03-29 18:50 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-28 14:54 [PATCH 0/1] get_nr_restart_syscall() should return __NR_ia32_restart_syscall if __USER32_CS Oleg Nesterov
2017-03-28 14:54 ` [PATCH 1/1] " Oleg Nesterov
2017-03-28 15:03 ` Andy Lutomirski
2017-03-28 16:27 ` Oleg Nesterov
2017-03-28 17:10 ` Andy Lutomirski
2017-03-29 15:05 ` Oleg Nesterov
2017-03-29 16:59 ` Andy Lutomirski
2017-03-30 15:28 ` Oleg Nesterov
2017-03-30 18:36 ` Andy Lutomirski
2017-03-29 16:33 ` syscall_get_error() && TS_ checks Oleg Nesterov
2017-03-29 16:45 ` Linus Torvalds
2017-03-29 16:55 ` Oleg Nesterov
2017-03-29 16:59 ` Linus Torvalds
2017-03-29 17:04 ` Oleg Nesterov
2017-03-29 17:16 ` Linus Torvalds
2017-03-29 18:50 ` Oleg Nesterov [this message]
2017-03-29 18:56 ` Linus Torvalds
2017-03-30 13:51 ` Oleg Nesterov
2017-03-30 15:49 ` Oleg Nesterov
2017-03-30 17:46 ` Linus Torvalds
2017-03-30 18:23 ` Andy Lutomirski
2017-03-30 18:35 ` Linus Torvalds
2017-03-30 18:59 ` Andy Lutomirski
2017-03-30 19:11 ` Linus Torvalds
2017-03-30 19:21 ` Andy Lutomirski
2017-03-30 19:29 ` Linus Torvalds
2017-03-29 16:56 ` Andy Lutomirski
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