From: David Miller <davem@davemloft.net>
To: viro@ZenIV.linux.org.uk
Cc: luto@kernel.org, torvalds@linux-foundation.org, mingo@kernel.org,
x86@kernel.org, linux-arch@vger.kernel.org,
linux-s390@vger.kernel.org
Subject: Re: [PATCH] Rename is_compat_task to in_compat_syscall
Date: Tue, 19 Jan 2016 17:16:43 -0500 (EST) [thread overview]
Message-ID: <20160119.171643.1125867148856105860.davem@davemloft.net> (raw)
In-Reply-To: <20160119215535.GU17997@ZenIV.linux.org.uk>
From: Al Viro <viro@ZenIV.linux.org.uk>
Date: Tue, 19 Jan 2016 21:55:36 +0000
> 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.
Correct.
next prev parent reply other threads:[~2016-01-19 22:16 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
2016-01-19 22:16 ` David Miller [this message]
2016-01-19 23:15 ` Andy Lutomirski
2016-01-20 8:58 ` Heiko Carstens
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