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 7BA723624A5; Sat, 3 Oct 2026 14:30:12 +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=1791037814; cv=none; b=TRoGuWOMvN38GLqR4y+OOG5HbgNrf2i2pDldQkWimOneJ7px+do1H/9UvbGYHxBJ9XzJ3ai/EKkD4LNVZsNFXV7+V/Re2LIVugnW0wTyLqpCT9dShmRKHXgB+KfG7lmaw6RevmfKsdhn7YFGSnUb3l7t6OFRMyX82yFyuJVyUMw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791037814; c=relaxed/simple; bh=t0UDno8TrYYCKqsnhBUcmiISR33g6wQpfmrIYgzFs6I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=oXrAGPhR6L/K2W2iNAIAZ5csq9G0uZ3ouitK6gGjYjPeMQ8PtzZat9O8tiE+5wnN/c7Aq+Lcly7Sb0dw3Jy1JqsfKONNzPKFx7y0ivKe8LNGQ0Y2Rsi+Czs3g2oM7kad4Pyl+l4KERrxF8PKvU+/q1NYl7BV8PLI968ajpreIpM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=G5nou7g3; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="G5nou7g3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BA99C1F0089D; Sat, 3 Oct 2026 14:30:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791037812; bh=0VOKNZsXt8POVkaKJcBsptOeZCCqTjnL2Hl8Rsw8LdQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=G5nou7g3BqkL8GO0V7LH3FWiz4Xoa6UoLxbdYyBRNRvGCkLhqMbp6+wA6pS2p/wVK sidohVIkYNtujZDVfUM350+FJ1wgxX60ajONcjnohTOYKxjQMkWAyWELf0CnGvr02Q gjohG0PwgaN8nLfzWqbu/L7Nia0F7RUnlNp248cYN3q92WlLgwaMyITpAQqEehfXjP sea+oh86kMUv9RdeT7EsCS9ncjSttPEBd3y2ixsVo0icKtKNxWC3oeZh/c3Q5WQ0Sk EhQsd9nLHWTRG2SBKA3cDpqFKNSGHPTNptvc7RmnmGg5bTdKrg/s5hmD3gnBUMZB7v QtpTiEniK6sSg== Date: Sat, 3 Oct 2026 10:30:10 -0400 From: Sasha Levin To: "Lorenzo Stoakes (ARM)" Cc: rppt@kernel.org, peterz@infradead.org, akpm@linux-foundation.org, david@kernel.org, mingo@redhat.com, acme@kernel.org, namhyung@kernel.org, linux-mm@kvack.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, regressions@lists.linux.dev, stable@vger.kernel.org, 4ncienth@gmail.com, alexander.motin@truenas.com, caleb.stjohn@truenas.com, ameer.hamza@truenas.com Subject: Re: [REGRESSION] secretmem: SIGBUS on memfd_secret() pages while perf record runs Message-ID: References: <20261002175651.811343-1-ameer.hamza@truenas.com> <2026-10-02-rc-reply-0003-re-secretmem-sigbus-perf@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: On Sat, Oct 03, 2026 at 10:18:34AM +0100, Lorenzo Stoakes (ARM) wrote: >On Fri, Oct 02, 2026 at 09:30:23PM -0400, Sasha Levin wrote: >> > Since commit 97d34aa65c29 ("mm/secretmem: properly account locked >> > pages"), in v7.3-rc2 and the 6.18.52 and 7.2.5 backports, touching a >> > memfd_secret() page for the first time fails with SIGBUS while the >> > same user is running perf record, and read() into such a page fails >> >> Thanks for the report. I've dropped 97d34aa65c29 from the 6.12 queue, >> and also removed the copies that were staged for 6.6 and 6.1. >> >> 7.2.y and 6.18.y already shipped it, so those need an upstream fix, >> which stable will pick up once it lands. > >Sasha, > >Could we perhaps take a breath and pause? I pulled this out quickly because I didn't want this issue to go into the kernels that were released this morning. In general, our policy around this type of reports is that if the issue is in a released LTS kernel, we will wait for a fix upstream, and if the issue is still in our queues, we will simply drop the patch from the queue. >This patch fixes a really quite serious vulnerability that allows an >unprivileged process to allocate arbitrary, unreclaimable (i.e. OOMK cannot >save you) memory. > >Allow me to assess the validity of this report _before_ dropping things >from queues perhaps? :) No disagreement that this would have been better - in this case it was timing as the releases were about to happen the following day, so the safest choice was to drop it while we figure it out. >It was sent late on Friday in a week that I was ill and it's Saturday >pre-LPC, so that's hardly a timeframe that I could reasonably have replied. Keep in mind that our release cycles are fairly short, so this shouldn't be too big of a deal? We will generally go for the safe option of dropping a commit that introduces a regression as it's fairly easy to queue it back up very soon after a diagnosis/fix shows up. -- Thanks, Sasha