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 351323002DD for ; Wed, 20 May 2026 10:38:39 +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=1779273523; cv=none; b=qJhUjDA0ooEV12oF8IgGZF/0CpenRUVM9N44vyrHc8wP8gAlheyTR49+8Ar2Mlxg5JSInvdJ8J01lkfq1fUi5VRaUXGTZGWdZAvgtJVIJ+yLBY/aRGTyezxMx0bDIqP0CrSv5oVzMHoNv/uWAHxgknSfFPEkT56QBUtL1AXm020= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779273523; c=relaxed/simple; bh=eDZp6cAC4Uiuns2k9OL8DbNAMY6B8eoNLJKar+wtNtk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Itl7B9Nn3Di4WIAEH2YxxXYxt9Z6pLILDUQqJqBdcptQSfAT4GR3h/V2FwnXre+lZCCzaBxn+vU1ZWzB7EOQGustMONipKIn/KmFMuy+JA5c8RAWv2Kn9QfHCx236x10qH0fFEmbycR/WR/FGvfzRyD9SyogkkcQwrfKzCI4zIQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gqaA4sPm; 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="gqaA4sPm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C78E81F000E9; Wed, 20 May 2026 10:38:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779273516; bh=zKHYUkO/I/cBGRIah7HMHfF9u0P/yu4dIBcDhYec6so=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=gqaA4sPm9GiPL95zqAzf4DlwDvm3yps/PysG5LJEvND2TMcMw+YmLTpkKj5M5ppdv JiH7OG3keLXsczoVtlV5VN24CgsHcN9rg0qBeyEj6uB6USshElukhvhlzCoNU63MxH 8KAoeawePHuRQibM7kVg911h+NBl3OSQtTPNgnYsenfF+2/N2VOC4gCU51OH3w9hLP T3SIDnCIut8oCzAkqu8FI7MWYd3fqbi1FePFd4FfRyXi1tM5KXVzWoLifEFc0oV/4q RczviGsy0711qdZ6s8Qs1ojsvrLHRL6rCacmAM9ZPE6KUm6mvyofbAJKFWpEXlJcce Wn0HEdDOIAYVg== Message-ID: <093c0351-9417-4567-b4fb-62691118271a@kernel.org> Date: Wed, 20 May 2026 12:38:30 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3] mm/memory-failure: fix hugetlb_lock AA deadlock in get_huge_page_for_hwpoison To: "Oscar Salvador (SUSE)" , Wupeng Ma Cc: muchun.song@linux.dev, osalvador@suse.de, akpm@linux-foundation.org, ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, linmiaohe@huawei.com, nao.horiguchi@gmail.com, mike.kravetz@oracle.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260520020128.3506168-1-mawupeng1@huawei.com> 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 5/20/26 10:13, Oscar Salvador (SUSE) wrote: > On Wed, May 20, 2026 at 10:01:28AM +0800, Wupeng Ma wrote: >> madvise(MADV_HWPOISON) can trigger a recursive spinlock self-deadlock >> (AA deadlock) on hugetlb_lock due to a race with concurrent folio >> unmapping. The race scenario: >> >> Thread 1 (madvise MADV_HWPOISON) Thread 2 (unmap) >> ------------------------------- ----------------- >> madvise_inject_error() >> get_user_pages_fast() <- refcount++ >> memory_failure(MF_COUNT_INCREASED) >> get_huge_page_for_hwpoison() >> spin_lock_irq(&hugetlb_lock) >> // refcount == 2 (gup + map) >> // MF_COUNT_INCREASED path: >> count_increased = true >> zap_pte_range() >> page_remove_rmap() >> put_page() <- drops map ref >> // refcount: 2 -> 1 > > Ok, bear with me. > I am not saying the change itself is wrong (maybe it is not), but how we ended > up in zap_pte_range() for a hugetlb folio? > The stacktrace does not seem to have much sense? Right, that does not make sense. Not even page_remove_rmap() makes sense, because that function is long gone. Undisclosed usage of shitty AI? -- Cheers, David