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 69776423EB4 for ; Thu, 24 Sep 2026 19:21:08 +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=1790277670; cv=none; b=VrdWVB68Tb0Fawbb8ZacXDbO+2awSjdSGOvhLROoOh9SmIQcXwoSS3AEZy6fY1FwNaOfCg2vHMayxNmKC0GvgWl2ncrA6OKWuVjZk1ms+jAQ5Aj/LMKoueEZbDXfzU6XpGbV2gfSI1IMVhfduHflQ4fFHJZiLVobtgEqQQv4Yz4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790277670; c=relaxed/simple; bh=qVdqf9CoS9eEGCaz5ubHg58DRGhzfwUChAJq4LgCxRI=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=VIqEsbax7BS3pETPUbG3gv9fyAIL1T8Hn5UGgiBT6N6lNkYeHUtCLLPwSJ1r+gQt6wsIwTwQpWTeYgOt54Uj3TWtjddzYqiGYngooeS6XSRIkr+g08JPP/NP/GmBe9Cm9r0hXF9h3+opGwsV6G2d7hdI1+0E5S4zNeke0VzTgEo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=f38RuqRb; 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="f38RuqRb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1759D1F000FF; Thu, 24 Sep 2026 19:21:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790277668; bh=WMAAGZRwKUNMIhAnHmdwYlinnRJBDD/spjkoWxSduck=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=f38RuqRb/jrM+Gu/zWGyEm8U1rNgYFWSu/zmUMeOkW75CjJN0V0r8lVTqRQ6O2MjE pVE4GWkkJqIxi0tRj1fuPyDFE6oauN0qrnN0tK7dvPO6UigbDVzzNDUtOiXHd6dpUQ Zynck6PTGpALVUAjh/In0G+ob1p0AjWhqt7GWgvbbIpOtSQX8gheKNvmsSNB+atxPp BlVTBYARoKk+uEsYkYWJGb6uaPmmqvUxcY5R9aJLTSiuZhebK2uQbngYX+xBgY32UH lq4GW3AxC90fT1d6vvnnf3UjFmc4eQMwH/cR0sESMpsUbIpETaK4y9H1voydMNDoKm TPmbIt/gBWkgQ== Message-ID: <7ae258ae-b694-43f5-8244-688ddd2ec666@kernel.org> Date: Thu, 24 Sep 2026 21:21:01 +0200 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v9 08/15] hugetlb: Use the has_hwpoisoned flag To: Matthew Wilcox Cc: Andrew Morton , Jane Chu , linux-mm@kvack.org, Muchun Song , Oscar Salvador , Miaohe Lin , Naoya Horiguchi , Jan Kara , linux-fsdevel@vger.kernel.org, Christian Brauner , Jiaqi Yan , "Gregory Price (Meta)" References: <20260805210557.1118966-1-willy@infradead.org> <20260805210557.1118966-9-willy@infradead.org> <7608c80e-645b-4d07-bba3-ef45ee36fba4@kernel.org> <7a23511f-365f-436f-b934-6a520510409c@kernel.org> <6121136c-de9d-4577-a30d-f00dbe244e5d@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 9/24/26 20:53, Matthew Wilcox wrote: > On Thu, Sep 24, 2026 at 12:32:13PM +0200, David Hildenbrand (Arm) wrote: >>> Oh, no, it's awful and complicated. We could strip out the two bugfixes >>> which are at the start of the series, but why would we want to do that? >> >> Andrew usually wants us to separate bugfixes (especially stable ones) from >> other work. Unless we all agree that they are not urgent and can go in in >> the next cycle. I assume that's the case here. > > I don't understand that preference, to be honest. As long as they're > first in the patch series, they're easy to pick out and don't depend > on the other patches in the series. I mean, I agree. However, Andrew tends to fault in the cover letter into the first patch and tracks them in one unit. > >> I am not convinced about the huge_poison thing though, that originally caught my >> attention. >> >> So trying to understand the race we are trying to solve (that is independent of >> the original idea of the patch set), I realize that these races are only on some >> slow paths we don't particularly care about for performance. > > They are not hot paths, I agree, but they are user-triggerable paths. You seem to assume that any of the users would be triggerable by unprivileged users? Remember: you need to operate on arbitrary PFNs without taking proper references. /proc/kcore? Certainly not. /proc/kpageflags? Certainly not. /sys/kernel/debug/hwpoison/unpoison-pfn or any other software poison injection? Certainly not. -- Cheers, David