From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id BAFF2C4452F for ; Tue, 21 Jul 2026 13:08:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TYa/G9Ikx6NJ1Cb3jjSRc0JJzXsBaNhe6e1UGVGm/9A=; b=Mnvq0gGjKIePw8mykkgAJJz0bM fyJ4113UcEJ142TCZv0iXdF0MTFijYjXUsQDhLulWw1T1jmLmAOLLq/0hJl7z84p7m0XieqAn5iuJ cJK3ToMXRbGAg1AY9TWla+5s3Y+amx+eNB8CkkUwis1PgFLZfp6ryMZQMFfCm8yMoFSr62vhDgFat lbfQPLQLDVJ67LwMBEAMkGBm4OXz+/utlOQwvEh0vDwvewa3obr2cyluZHmc1KnN0YSP1lAB66+xa 3UfP5la64Lijb0pCnLvAlWmvsTAVDAHXOR8ycMbh9eGhp6CGpvxnxGK4tioRbvr3ILojpIK+/vb1D j2xJcFfA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wmACt-00000009UFl-1C5T; Tue, 21 Jul 2026 13:08:23 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wmACr-00000009UFa-2PPR; Tue, 21 Jul 2026 13:08:21 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 4BA4841AC7; Tue, 21 Jul 2026 13:08:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2A081F00A3A; Tue, 21 Jul 2026 13:08:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784639301; bh=TYa/G9Ikx6NJ1Cb3jjSRc0JJzXsBaNhe6e1UGVGm/9A=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=d6/V2aPEpPAB2I6Ua7LPwlcHwngi1zJi/XHIgdgpWsC+OpJGb8lJA2aRw5XgvUCSk 5IZrdAIm+bmynNmQblXUQu5K3mThBRK4gT3ERximvLzMKDANxWBbmBkq/iBUG9clUc 4TcfxO32nUe0BTZC9S93Hw6aq20MtO0npuydVBV4= Date: Tue, 21 Jul 2026 15:08:11 +0200 From: Greg Kroah-Hartman To: Pawan Gupta Cc: stable@vger.kernel.org, Sasha Levin , bpf@vger.kernel.org, linux-arm-kernel@lists.infradead.org, loongarch@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, x86@kernel.org, Alexei Starovoitov , Daniel Borkmann , Dave Hansen Subject: Re: [PATCH 6.16.y 0/6] cBPF JIT spray hardening Message-ID: <2026072151-outsell-suburb-64ea@gregkh> References: <20260714-cbpf-jit-spray-hardening-6-16-y-v1-0-2fc3e16263ac@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260714-cbpf-jit-spray-hardening-6-16-y-v1-0-2fc3e16263ac@linux.intel.com> X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, Jul 14, 2026 at 11:58:24AM -0700, Pawan Gupta wrote: > Hi, > > These backports harden BPF JIT against spectre-v2 class of attacks. Without > a predictor flush, execution of new BPF program may use stale prediction > left behind by the freed one. > > To avoid this, issue an IBPB flush on all CPUs on JIT program allocation. > The flush is conditional to spectre-v2 mitigation applied. > > Patch 1-2: Adds the predictor flush hook and enables it on x86 via IBPB. > > bpf: Support for hardening against JIT spraying > x86/bugs: Enable IBPB flush on BPF JIT allocation > > Patch 3-6: Narrow the flush to only unprivileged JIT allocations > to avoid redundant flushes. Also adds pack-selection changes > that minimizes flushes. > > bpf: Restrict JIT predictor flush to cBPF > bpf: Skip redundant IBPB in pack allocator > bpf: Prefer packs that won't trigger an IBPB flush on allocation > bpf: Prefer dirty packs for eBPF allocations > > This one is mostly similar to 6.18: > > https://lore.kernel.org/all/20260713-cbpf-jit-spray-hardening-6-18-y-v1-0-755f60c55705@linux.intel.com/ There is no active 6.16.y kernel branch, so why is this being sent to us? confused, greg k-h