From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752461AbdJCPYp (ORCPT ); Tue, 3 Oct 2017 11:24:45 -0400 Received: from mail.kernel.org ([198.145.29.99]:41226 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752357AbdJCPYm (ORCPT ); Tue, 3 Oct 2017 11:24:42 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7A21B21869 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=mhiramat@kernel.org Date: Wed, 4 Oct 2017 00:24:37 +0900 From: Masami Hiramatsu To: Ingo Molnar Cc: mingo@redhat.com, x86@kernel.org, Steven Rostedt , linux-kernel@vger.kernel.org, Peter Zijlstra , Ananth N Mavinakayanahalli , Thomas Gleixner , "H . Peter Anvin" , "Paul E . McKenney" , Alexei Starovoitov , Alexei Starovoitov Subject: Re: [BUGFIX PATCH] kprobes/x86: Remove IRQ disabling from jprobe handlers Message-Id: <20171004002437.66c15c68ef662c0d9a458bef@kernel.org> In-Reply-To: <20171003093344.feh7gqa4aimsjwqv@gmail.com> References: <20170930231251.emiuyrapdgzpcylp@inn> <150701508194.32266.14458959863314097305.stgit@devbox> <20171003093344.feh7gqa4aimsjwqv@gmail.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 3 Oct 2017 11:33:44 +0200 Ingo Molnar wrote: > > * Masami Hiramatsu wrote: > > > Jprobe actually doesn't need to disable IRQs while calling > > handlers, because Documentation/kprobes.txt says: > > > > ----- > > Probe handlers are run with preemption disabled. Depending on the > > architecture and optimization state, handlers may also run with > > interrupts disabled (e.g., kretprobe handlers and optimized kprobe > > handlers run without interrupt disabled on x86/x86-64). > > ----- > > > > So let's remove IRQ disabling from jprobes too. > > > > Signed-off-by: Masami Hiramatsu > > --- > > arch/x86/kernel/kprobes/core.c | 2 -- > > 1 file changed, 2 deletions(-) > > > > diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c > > index b48e0efd668e..bd36f3c33cd0 100644 > > --- a/arch/x86/kernel/kprobes/core.c > > +++ b/arch/x86/kernel/kprobes/core.c > > @@ -1099,8 +1099,6 @@ int setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs) > > * raw stack chunk with redzones: > > */ > > __memcpy(kcb->jprobes_stack, (kprobe_opcode_t *)addr, MIN_STACK_SIZE(addr)); > > - regs->flags &= ~X86_EFLAGS_IF; > > - trace_hardirqs_off(); > > regs->ip = (unsigned long)(jp->entry); > > > > /* > > Could you please also do a patch that disables jprobes permanently, in preparation > of eventually removing them later? Would you mean introducing CONFIG_JPROBE_API and cut APIs out, or just adding "__deprecated" for each API? Thank you, > > Thanks, > > Ingo -- Masami Hiramatsu