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 DE6CB50B8DC; Fri, 18 Sep 2026 15:54:13 +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=1789746855; cv=none; b=gdJJZXn6mVN1J1JOtDNbJVmwJE0jxcguEgKOmMhgsSGV6NSiHAMISyKLmf3mU4ESMyy3RsPW7ODEqhELVJSamQbL5S/1an9b28WekscTm80h8jjSGNJ/fTx8Dnkv/u+AqRzeGXEHdS9lqUqB/faEWdVPHXnTBchh8ktTtV20kWA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789746855; c=relaxed/simple; bh=gizjOLNO7p3fkn5KhEpxbFmH7YV/glWqfh5W5hVhTuc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ebJaw4YAFpJnGIVPrI0A1EyqFizVrkm6yCEDOvehJtdq7HrOyiCCBSgfio607bUOj2CmgbiIALR1wVzaZ4pbPy5UzV1l8FmypiIzdMawkALMdxVxCRjOz6VR0eENVdDpCeUM82JA0DEo/cfODQIQn1OrsJ9nyK535UhotlvM3Hc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dvJ05ect; 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="dvJ05ect" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B924C1F00899; Fri, 18 Sep 2026 15:54:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789746853; bh=jzZyR2opvhg/Uisj+jtHQQdTUCKbVRbCE+wjZ5A5TP0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=dvJ05ecto1t06MSKZtLbey4Kpyu5wczps7vqBRXBnli9r2Sdqck6iVRHbFwyQUlR4 851973NA0P37rU38lWaGF7r5vKSi1JDDeC2lUL4JNOF5o/RzLhwxXHfBTXAh1Fy0AC jYyrTxuddUB7c+P9BjFtTGC/YPQDuMbO8jvZgTNXzMPhU94bYX5Ojw77RAC3eKdx1L H4Y/zv4tldllfT7zh2mc24bEG9c/u55QdmXtkwOf0+swLXWW+hoRntW4P5mxy9GsLW Eg6oC7N43vM4hJEG2fKphrLUX6oCgQG5WFFMug4UunJfsUa7wukQDcEEze7wEZmNb5 xjb7SUVoqbmmA== From: Sasha Levin To: Greg Kroah-Hartman Cc: Sasha Levin , stable@vger.kernel.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, linux@roeck-us.net, shuah@kernel.org, patches@kernelci.org, lkft-triage@lists.linaro.org, pavel@nabladev.com, jonathanh@nvidia.com, f.fainelli@gmail.com, sudipm.mukherjee@gmail.com, rwarsow@gmx.de, conor@kernel.org, hargar@microsoft.com, broonie@kernel.org, achill@achill.org, sr@sladewatkins.com, Brett A C Sheffield Subject: Re: [PATCH 6.12 0000/1102] 6.12.111-rc1 review Date: Fri, 18 Sep 2026 11:54:03 -0400 Message-ID: <20260918151136.2101477301-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: References: <20260917151539.408551884@linuxfoundation.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Thu, Sep 17, 2026 at 07:35:34PM +0000, Brett A C Sheffield wrote: > 6.12.111-rc1 hangs on boot on this machine (AMD Ryzen 9 9950X). [...] > # first 'bad' commit: [22ae428b0045981bd19f8c75f700a67198062f32] > mm/hugetlb: initialize gigantic bootmem hugepage struct pages earlier Thanks for the bisect, it lands exactly on the problem. Dropped from the 6.12 queue: b1b7c045e808 ("mm/hugetlb: initialize gigantic bootmem hugepage struct pages earlier") For the record, why it breaks only on 6.12: the backport moves gather_bootmem_prealloc() out of hugetlb_init() (a subsys_initcall) into page_alloc_init_late(), which runs well before do_basic_setup(). Upstream that reordering is safe because since v6.15 the per-node huge_boot_pages[] list heads are initialized unconditionally and very early in hugetlb_bootmem_alloc(). 6.12 has neither that function nor the commits that added it, so the only INIT_LIST_HEAD() of those lists is the lazy loop in hugetlb_hstate_alloc_pages(), reached early only when a gigantic hugepage is requested on the command line. Boot a CONFIG_HUGETLB_PAGE=y kernel without hugepagesz=/hugepages= and the relocated code walks an all-zero list head, so the first iteration dereferences NULL. Nothing else in the queue depended on it, so it comes out on its own. -- Thanks, Sasha