From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from madrid.collaboradmins.com (madrid.collaboradmins.com [46.235.227.194]) (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 1048C4402; Mon, 15 Jan 2024 07:49:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="R4JcS7dy" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1705304980; bh=N3XCgFDqk2GrOitAp3uyTP3EuoDEu1xWts+NDkUZPHA=; h=Date:Cc:Subject:To:References:From:In-Reply-To:From; b=R4JcS7dyyz17O7mEwJV5qf5f1nlW0Mo+tFwR2hRBttaxbdHrHFV9bu112yi4NmNKM WePKXscCqpfwoLQdSrq8LmRyrU4+p9e8B34nesX4bKlSywDbP9KZPCa/OwAGHd/Jil 5XVZOLJ4FoAPN6lbdhWFd8ea8wJVkPuFP2rhjq2HCg2F6E+UiUQZSWvpWzUugebhuM DsE9N3xhNK/swZdhrk+IyRRLu/HkES7LqIYI9bmHueOrj+ZXApD3fQTL2BlUgcWiHY H9gUgEg9fTLL10FK0z7xgB9vjaBV5fSby/gTseJ/EHR+MGvTu3HiqaKkFMjLAK1t3r sDyeDvE6peUmg== Received: from [100.96.234.34] (cola.collaboradmins.com [195.201.22.229]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: usama.anjum) by madrid.collaboradmins.com (Postfix) with ESMTPSA id 4264D37813DD; Mon, 15 Jan 2024 07:49:37 +0000 (UTC) Message-ID: Date: Mon, 15 Jan 2024 12:49:45 +0500 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: Muhammad Usama Anjum , akpm@linux-foundation.org, muchun.song@linux.dev, jiaqiyan@google.com, willy@infradead.org, linmiaohe@huawei.com, naoya.horiguchi@nec.com, shy828301@gmail.com, jthoughton@google.com, jane.chu@oracle.com, stable@vger.kernel.org, "kernel@collabora.com" Subject: Re: [PATCH v2] fs/hugetlbfs/inode.c: mm/memory-failure.c: fix hugetlbfs hwpoison handling Content-Language: en-US To: Sidhartha Kumar , linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20240112180840.367006-1-sidhartha.kumar@oracle.com> From: Muhammad Usama Anjum In-Reply-To: <20240112180840.367006-1-sidhartha.kumar@oracle.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/12/24 11:08 PM, Sidhartha Kumar wrote: > has_extra_refcount() makes the assumption that the page cache adds a ref > count of 1 and subtracts this in the extra_pins case. Commit a08c7193e4f1 > (mm/filemap: remove hugetlb special casing in filemap.c) modifies > __filemap_add_folio() by calling folio_ref_add(folio, nr); for all cases > (including hugtetlb) where nr is the number of pages in the folio. We > should adjust the number of references coming from the page cache by > subtracing the number of pages rather than 1. > > In hugetlbfs_read_iter(), folio_test_has_hwpoisoned() is testing the wrong > flag as, in the hugetlb case, memory-failure code calls > folio_test_set_hwpoison() to indicate poison. folio_test_hwpoison() is the > correct function to test for that flag. > > After these fixes, the hugetlb hwpoison read selftest passes all cases. > > Fixes: a08c7193e4f1 ("mm/filemap: remove hugetlb special casing in filemap.c") > Closes: https://lore.kernel.org/linux-mm/20230713001833.3778937-1-jiaqiyan@google.com/T/#m8e1469119e5b831bbd05d495f96b842e4a1c5519 > Cc: # 6.7+ > Signed-off-by: Sidhartha Kumar > Reported-by: Muhammad Usama Anjum Tested-by: Muhammad Usama Anjum > --- > > v1 -> v2: > move ref_count adjustment to if(extra_pins) block as that represents > ref counts from the page cache per Miaohe Lin. > > fs/hugetlbfs/inode.c | 2 +- > mm/memory-failure.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/fs/hugetlbfs/inode.c b/fs/hugetlbfs/inode.c > index 36132c9125f9..3a248e4f7e93 100644 > --- a/fs/hugetlbfs/inode.c > +++ b/fs/hugetlbfs/inode.c > @@ -340,7 +340,7 @@ static ssize_t hugetlbfs_read_iter(struct kiocb *iocb, struct iov_iter *to) > } else { > folio_unlock(folio); > > - if (!folio_test_has_hwpoisoned(folio)) > + if (!folio_test_hwpoison(folio)) > want = nr; > else { > /* > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > index d8c853b35dbb..ef7ae73b65bd 100644 > --- a/mm/memory-failure.c > +++ b/mm/memory-failure.c > @@ -976,7 +976,7 @@ static bool has_extra_refcount(struct page_state *ps, struct page *p, > int count = page_count(p) - 1; > > if (extra_pins) > - count -= 1; > + count -= folio_nr_pages(page_folio(p)); > > if (count > 0) { > pr_err("%#lx: %s still referenced by %d users\n", -- BR, Muhammad Usama Anjum