linux-kernel - Re: [PATCH 2/5] uprobes: introduce uprobe_switch

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: <1322510018.2921.161.camel@twins>
Date:	Mon, 28 Nov 2011 20:53:38 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Oleg Nesterov <oleg@...hat.com>
Cc:	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux-mm <linux-mm@...ck.org>, Ingo Molnar <mingo@...e.hu>,
	Andi Kleen <andi@...stfloor.org>,
	Christoph Hellwig <hch@...radead.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Roland McGrath <roland@...k.frob.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Arnaldo Carvalho de Melo <acme@...radead.org>,
	Anton Arapov <anton@...hat.com>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Jim Keniston <jkenisto@...ux.vnet.ibm.com>,
	Stephen Wilson <wilsons@...rt.ca>
Subject: Re: [PATCH 2/5] uprobes: introduce uprobe_switch_to()

On Mon, 2011-11-28 at 20:06 +0100, Oleg Nesterov wrote:
> +void uprobe_switch_to(struct task_struct *curr)
> +{
> +       struct uprobe_task *utask = curr->utask;
> +       struct pt_regs *regs = task_pt_regs(curr);
> +
> +       if (!utask || utask->state != UTASK_SSTEP)
> +               return;
> +
> +       if (!(regs->flags & X86_EFLAGS_TF))
> +               return;
> +
> +       set_xol_ip(regs);
> +} 

> void __weak set_xol_ip(struct pt_regs *regs)
>  {
> +       int cpu = smp_processor_id();
> +       struct uprobe_task *utask = current->utask;
> +       struct uprobe *uprobe = utask->active_uprobe;
> +
> +       memcpy(uprobe_xol_slots[cpu], uprobe->insn, MAX_UINSN_BYTES);
> +
> +       utask->xol_vaddr = fix_to_virt(UPROBE_XOL_FIRST_PAGE)
> +                               + UPROBES_XOL_SLOT_BYTES * cpu;
> +       set_instruction_pointer(regs, utask->xol_vaddr);
>  }

So uprobe_switch_to() will always reset the IP to the start of the slot?
That sounds wrong, things like the RIP relative stuff needs multiple
instructions.


--
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/