From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 97B4530BF6D; Tue, 21 Jul 2026 13:08:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784639302; cv=none; b=aM+9BtO+R53L455qQoC355Grk+FigR5tOU7bxe6+CKSfOr/KykYTKn4sEunbp03CCZuhjSTgyisBbYFEs7dpKzrCtpyfEeuwPrfMJXMUNNMsyKAyvO8RCBcMDMkS8wdvR/ki5w61b1SmMs3QIznzGniJuZTFjFfqFH8ehr8ljH8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784639302; c=relaxed/simple; bh=rcAygpI/OJg3FVWLYpuLgsXPmMSPCIccC5rzw7T21IE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VWvEzj16Oc8o2ZTmL2aK3RifEK1FCkoQFwhlDg1Y98JbLDR5wKlr2C09IJM2WL7N63BCO6184Hq8COP0lJDvuTwv5GcRScO+zvMgJbwJxizIYa8jT7oDy3tep6Z0T39GdQoG84iyRWCvI9WxhgfWqIGz+ns5wPCgt1NExZjxWhg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=d6/V2aPE; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="d6/V2aPE" 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> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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> 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