From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 F19CF3C73D2 for ; Thu, 19 Mar 2026 11:13:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773918786; cv=none; b=RdupwN0qOC2Fozndex31ux0bjizpg/umR/jFvywdC/B1VGJxNFcX8f/4hyLk4xK/PghY/lTXG+p8YeDcPQdQ4T6vAYVPrFBqS9gwM2DcTCFcLwE1PZdBtANmQJCsBbL9hjMmELQVK7ANz8149LJ1kxpuIdsP9hju3E4Om0kleAE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773918786; c=relaxed/simple; bh=4aGhCkvep3z4IGyK/eGTBo8Z0Wlsdk46Z7iUmouA25s=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=WUzONh5Hg80LHPh9odEnr9t1XcKNq0aDawKAPLptsX9T7+QxV7OcMr5uluQilikzgajw2XergxFb4GM2sLnymB1hVn6tNhNruo3UOZCj/0yqW/e7Bs2Y/zcFKP/tO83aThFmnGHNIVXD1XfcR6S5dutp2aqrCNugo7DYpna8i9E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oGEsB6fb; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oGEsB6fb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5AEB0C2BCAF; Thu, 19 Mar 2026 11:13:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773918785; bh=4aGhCkvep3z4IGyK/eGTBo8Z0Wlsdk46Z7iUmouA25s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oGEsB6fbV/dzhN37U1+RQ28sdVXA7PV+Jhd23VCCc+m5vRC4YFVWL63sjPl5Z83UT sHcQuNkGTTugbpeJ6266kYcCVb8QGuK0LQEOzfsKwPsBtzNJWezcytbztyPa1gmuVU FnTYCjFRtbID+jp/GOdlTRMdpbmi04RQdpjF1cgvAQI/zlwGyb5E4RzCzSY9j0DDDW WbM3MsTVHumEgm9UduB1aKyeF1dvNhib7upT+Urp//4wdQ8tZC/Ycb7JeGBIi0bBGO g2W2/yJ2QSAneLThgB8/4GckV6yVcR0IKiphUzjGSnK8jsFXBv4JxKClFa3r933o+e eXabq9uB5ahtA== Date: Thu, 19 Mar 2026 11:12:59 +0000 From: "Lorenzo Stoakes (Oracle)" To: "David Hildenbrand (Arm)" Cc: Lance Yang , syzbot , willy@infradead.org, baolin.wang@linux.alibaba.com, npache@redhat.com, linux-mm@kvack.org, baohua@kernel.org, ryan.roberts@arm.com, syzkaller-bugs@googlegroups.com, dev.jain@arm.com, ziy@nvidia.com, linux-kernel@vger.kernel.org, Liam.Howlett@oracle.com, akpm@linux-foundation.org Subject: Re: [syzbot] [mm?] kernel BUG in collapse_scan_file Message-ID: <024ed30f-db2d-403d-ad3a-3e74a55c6a4a@lucifer.local> References: <69bba3c0.050a0220.227207.002b.GAE@google.com> <10e5f1d6-077d-4783-aa16-6c8b98cb9e74@lucifer.local> <8ab10631-4672-4196-b32e-7c5a01707424@kernel.org> <37b48d94-9576-4529-8576-d4ed615d4768@kernel.org> <5a4fc5ba-ab0b-4294-9577-9b5ee30b2c56@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 Content-Disposition: inline In-Reply-To: <5a4fc5ba-ab0b-4294-9577-9b5ee30b2c56@kernel.org> On Thu, Mar 19, 2026 at 12:10:36PM +0100, David Hildenbrand (Arm) wrote: > >> "This isn't the kind of thing where you can just jump in with a one line > >> patch and actually be helpful, sorry." > > > > > > Yup, so again really I don't think the kernel should take the xarray debug patch > > until it is discussed and verified as correct on-list. > > > > See the discussion with Vlastimil. > > Agreed. > > > > >> > >> So I am clueless if there is a real problem there or whether it's just a > >> false positive. And whether (if it's a real problem) the simple fix > >> would actually be a good temporary fix ("make other bugs more likely"). > >> > >> I can try finding some time to look into that, but pagecache code is not > >> particularly the code I'm familiar with ... > > > > I don't think we should waste our time on it, willy's series should be yoinked > > until it can prove itself for-sure well behaved. > > I hear you. At the same time it has the smell of "test case fails, so > let's remove the test case" vibes. > > Well, arguable, it's worse than a test case that fails :( > > I'm fine with dropping that asap. At the same time, I hope we won't lose > our reminder that something possibly bad is broken upstream. I mean hopefully once we have a _working_ version of this it will get reflagged again in any case. The uncertainty makes this worse than a bug report unfortunately because it's a maybe/maybe not and there's literally nothing we can do with that :( > > -- > Cheers, > > David Thanks, Lorenzo