linux-kernel - Re: [PATCH] x86: make PTRACE_GETREGSET return 32-bit regs if 64-bit process entered kernel with int 80

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20130215150940.GA31861@redhat.com>
Date:	Fri, 15 Feb 2013 16:09:40 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Cyrill Gorcunov <gorcunov@...nvz.org>
Cc:	Denys Vlasenko <dvlasenk@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, linux-kernel@...r.kernel.org,
	Andi Kleen <andi@...stfloor.org>,
	Pavel Emelyanov <xemul@...allels.com>
Subject: Re: [PATCH] x86: make PTRACE_GETREGSET return 32-bit regs if
	64-bit process entered kernel with int 80

On 02/15, Cyrill Gorcunov wrote:
>
> > strace needs to get that data on every syscall entry in the traced process.
> > Doing open/read/close on every syscall entry is going to slow it down a lot.
>
> Don't you need to read it only once when strace is attached? Compat flag can't
> be arbitrary dropped when program executes, no?

TS_COMPAT is set/cleared every time a 64bit task does int80.

I guess you need TIF_IA32, not TS_COMPAT, for c/r.

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/