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 F253B446052 for ; Wed, 23 Sep 2026 07:20:03 +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=1790148007; cv=none; b=CnU2DE4LjAjwU4g4zEXOhoMFhGKFXyNJT5AHRxXpoVdw11Pqm/UnYQW0SAa8b9ZY5Dkl8uPbP/HUlEiiCyXburXS8RD5V6i3kDs/RHsvzCx2rF9rZ53VyfpeauVaDrqcmfJWsTQmfU7HoZ1N7GjXIHgHt9AJ1tl+MLhF574W03s= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790148007; c=relaxed/simple; bh=Z5HXik1TEpwNXoISK6jKd9g0KtaddSbZS8dem+QPyBA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=BPmM5v5d9GNv6LmzVBPeDUWXba3W0MZxIpIzVtHpDVh00baXWlYNagWXQ9IDb1iIWkw1jsLSsPBYQ2ETXx9pZGA9bnpeVMJgQDGiufOsw+Xhfio1nQKoEn0366nsIIiCB/tXf72dK6SFSM4MU4uu3YMsVzlsYIYHzp/tETNMNlg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=jhvQCiG6; 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="jhvQCiG6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CF0F71F0089C; Wed, 23 Sep 2026 07:20:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790148001; bh=iV6tsPP7FMUE2ViOpQrvTbhHAu4oOtyI3MUTKdllcOA=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=jhvQCiG6/YGN8Pxn++L5bTH238GbAIufSXR1wQdDnw4WCL5jU8ekiza+bTatAwGaD 4HFlhWZrhAy/kSBS8On3MqeaMk62iqd+u2+/ViQPmd/PzYBJnrF7/KTjtOQBuDpdy8 aUKoT71f7B25a+xfXfaNQhJCVB8ewTMS4rRXNjYOMHDr0fzUT+jJxelbxX8viRX2T/ joMGcTMZywAhL2obJ8w5cAFOzlIECDsLC5hYOt6etyCTPoEnW9eROjZlH4bUsRZpq1 EhxSPfzR9ZiI3lSx3zh0GRoCFZVKtXFw2hSDVqMsvwPoAh++0thI61AYPDlcaApa8S hxcoENcM9x3PA== Date: Wed, 23 Sep 2026 00:20:01 -0700 From: Kees Cook To: "Guilherme G. Piccoli" Cc: tony.luck@intel.com, linux-hardening@vger.kernel.org, kernel-dev@igalia.com, kernel@gpiccoli.net Subject: Re: [PATCH 0/2] Small improvements on pstore user experience Message-ID: <202609230016.101B0479BF@keescook> References: <20260922212532.98571-1-gpiccoli@igalia.com> Precedence: bulk X-Mailing-List: linux-hardening@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: <20260922212532.98571-1-gpiccoli@igalia.com> On Tue, Sep 22, 2026 at 06:19:00PM -0300, Guilherme G. Piccoli wrote: > Hi Kees, Tony, > > Here are some small things I've noticed in pstore usage that annoyed > me a bit, so it's not they must be fixed - no bugs here that I can't see. > > But the fact kmsg_bytes can be changed via mount option but I can't > write on its sysfs parameter, or that I can set compression to like > "zstd" even when PSTORE_COMPRESS is unset, is a bit confusing to the > point I tried to improve them with these patches heh Thanks for poking at it! Yeah, that PSTORE_COMPRESS=n seems like it needs to get fixed. :P > Thanks for reviews and comments, and feel free to reject them if in > your opinion, they make things worse. Sashiko has some notes: https://sashiko.dev/#/patchset/20260922212532.98571-1-gpiccoli%40igalia.com I fear it is uncovered some other (small) preexisting issues, but I do agree the kmsg_bytes concurrency race is troublesome. -Kees -- Kees Cook