From: Al Viro <viro@ZenIV.linux.org.uk>
To: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
x86@kernel.org, linux-arch@vger.kernel.org,
David Miller <davem@davemloft.net>,
linux-s390@vger.kernel.org
Subject: Re: [PATCH] Rename is_compat_task to in_compat_syscall
Date: Tue, 19 Jan 2016 21:55:36 +0000 [thread overview]
Message-ID: <20160119215535.GU17997@ZenIV.linux.org.uk> (raw)
In-Reply-To: <79347eb4ec12be34098b36693bcf613eb597cbe9.1453239942.git.luto@kernel.org>
On Tue, Jan 19, 2016 at 01:47:24PM -0800, Andy Lutomirski wrote:
> Essentially all users of is_compat_task in the kernel are trying to
> determine whether they are executing in the context of a compat
> syscall. On at least x86_64 and sparc, these are not at all the
> same question.
>
> On x86_64 and sparc, therefore, is_compat_task doesn't return the
> overall compat state of the task; it returns true if the task is
> currently in a compat syscall.
The hell it does. Andy, TIF_32BIT is *NOT* set on syscall entry; it is
set by execve(). And 64bit task (with that bit clear) can bloody well
issue 32bit syscalls. Really.
next prev parent reply other threads:[~2016-01-19 21:55 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-19 21:47 [PATCH] Rename is_compat_task to in_compat_syscall Andy Lutomirski
2016-01-19 21:55 ` Al Viro [this message]
2016-01-19 22:16 ` David Miller
2016-01-19 23:15 ` Andy Lutomirski
2016-01-20 8:58 ` Heiko Carstens
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