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[23.128.96.18]) by mx.google.com with ESMTP id n12si1151361ejz.288.2020.08.26.02.24.19; Wed, 26 Aug 2020 02:24:41 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=fail header.i=@infradead.org header.s=casper.20170209 header.b=WdKgJulh; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727994AbgHZJVT (ORCPT + 99 others); Wed, 26 Aug 2020 05:21:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38952 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727884AbgHZJVT (ORCPT ); Wed, 26 Aug 2020 05:21:19 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04C1FC061574 for ; Wed, 26 Aug 2020 02:21:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=NbwHyk1VAR3OEivAV0SZE4FfPvn97BA/drW79Zx1uN0=; b=WdKgJulhEjoC3edg6mrrdZ3bdE A/KywDLwKdzQb3RNg/XPFSaA8vL6nvFJMvnc4CtyJovROEltahA7Mq8VGUJMS4Bmm1VnCNdjwyWnz QZAG9xIt7VlZEJjF0L+HLo57X44HC/232qVUPG7sDrIYQyjsGekguqHYszAt+jETowe3ihQ38c22p l0nDByRm99ET46Mq+6niARKSQT17zR3DG/lSjaSoibLzLlbOlJTSdCVAT2L2lcyPOXpIwceE8unvn nbP4R85PZ/+tvO9P+GqEAUKS3bkNEcl3oRS5zL7CLxe7Ju8rjWAqS3cbIImF4wAM7wxGGh15Uh3Vq rUDCd+Xg==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1kArcJ-0004Og-GV; Wed, 26 Aug 2020 09:21:15 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 3364D301A66; Wed, 26 Aug 2020 11:21:13 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 199322B79CD3E; Wed, 26 Aug 2020 11:21:13 +0200 (CEST) Date: Wed, 26 Aug 2020 11:21:13 +0200 From: peterz@infradead.org To: "Eddy_Wu@trendmicro.com" Cc: Masami Hiramatsu , "linux-kernel@vger.kernel.org" , "x86@kernel.org" Subject: Re: x86/kprobes: kretprobe fails to triggered if kprobe at function entry is not optimized (trigger by int3 breakpoint) Message-ID: <20200826092113.GS35926@hirez.programming.kicks-ass.net> References: <8816bdbbc55c4d2397e0b02aad2825d3@trendmicro.com> <20200825005426.f592075d13be740cb3c9aa77@kernel.org> <7396e7b2079644a6aafd9670a111232b@trendmicro.com> <20200825151538.f856d701a34f4e0561a64932@kernel.org> <20200825120911.GX1362448@hirez.programming.kicks-ass.net> <20200826090102.GC1362448@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200826090102.GC1362448@hirez.programming.kicks-ass.net> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 26, 2020 at 11:01:02AM +0200, peterz@infradead.org wrote: > Known broken archs include: Sparc32-SMP, PARISC, ARC-v1-SMP. > There might be a few more, but I've forgotten. Note that none of those actually have NMIs and llist is mostly OK on those architectures too. The problem is when you combine cmpxchg() with regular stores and llist() doesn't do that. The only architectures that have NMIs are: ARM, ARM64, POWERPC, s390, SH, SPARC64, X86 and XTENSA and all of them have sane atomic ops. (XTENSA is tricky, because it looks like it has parts that don't have sane atomics, but I _think_ those parts also don't have NMI)