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Mon, 24 Feb 2025 21:59:25 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.22.65.50]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 7E206180035F; Mon, 24 Feb 2025 21:59:23 +0000 (UTC) From: Luiz Capitulino To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, david@redhat.com, yuzhao@google.com, pasha.tatashin@soleen.com Cc: akpm@linux-foundation.org, hannes@cmpxchg.org, muchun.song@linux.dev, luizcap@redhat.com Subject: [PATCH v2 3/4] mm: page_table_check: use new iteration API Date: Mon, 24 Feb 2025 16:59:07 -0500 Message-ID: <30d246e83e73073451dc3d5fe189b733afbefd07.1740434344.git.luizcap@redhat.com> In-Reply-To: References: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 X-Rspam-User: X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 2CA6B4000C X-Stat-Signature: 5zjkpc6b5txuyeoq83fennb9qkr3u5j3 X-HE-Tag: 1740434371-649694 X-HE-Meta: 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 pKl/EFMP ALhlqqq9AyKnciklvqGiv4JQ3XS2HM8Sa7xEyWMZnDc3lIbkEZC1SUexKhTDhe5eYbSpG7wFhyElgmhquKC7+GtWFS6HqbEZIXws0ofRnl+VL+Pws0/reikBOKqSKwn2jZpdYu5FBA9C86Kpv39M92wSv7XsIBKNiUGQ6TuJJzOMlE5FhiHJc786kx/0jn20Pkc28VJ6c2thkeqhyVeSoptagUQHworcy25Z/jKaoXhOCVVQP3wRodRXB9AeMOJTuuP61kdnu2oC/5mDjynoCc+RjRWr3d7u738JzIQsv57bC0yMokmeOcItowEVSGUTTCjUww8hg927Bb1fZuNYLq6Z7iloA5Ko3YZDVb3KFMjZIxGGITA2V04gBxg== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The page_ext_next() function assumes that page extension objects for a page order allocation always reside in the same memory section, which may not be true and could lead to crashes. Use the new page_ext iteration API instead. Fixes: cf54f310d0d3 ("mm/hugetlb: use __GFP_COMP for gigantic folios") Signed-off-by: Luiz Capitulino --- mm/page_table_check.c | 39 ++++++++++++--------------------------- 1 file changed, 12 insertions(+), 27 deletions(-) diff --git a/mm/page_table_check.c b/mm/page_table_check.c index 509c6ef8de400..e11bebf23e36f 100644 --- a/mm/page_table_check.c +++ b/mm/page_table_check.c @@ -62,24 +62,20 @@ static struct page_table_check *get_page_table_check(struct page_ext *page_ext) */ static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt) { + struct page_ext_iter iter; struct page_ext *page_ext; struct page *page; - unsigned long i; bool anon; if (!pfn_valid(pfn)) return; page = pfn_to_page(pfn); - page_ext = page_ext_get(page); - - if (!page_ext) - return; - BUG_ON(PageSlab(page)); anon = PageAnon(page); - for (i = 0; i < pgcnt; i++) { + rcu_read_lock(); + for_each_page_ext(page, pgcnt, page_ext, iter) { struct page_table_check *ptc = get_page_table_check(page_ext); if (anon) { @@ -89,9 +85,8 @@ static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt) BUG_ON(atomic_read(&ptc->anon_map_count)); BUG_ON(atomic_dec_return(&ptc->file_map_count) < 0); } - page_ext = page_ext_next(page_ext); } - page_ext_put(page_ext); + rcu_read_unlock(); } /* @@ -102,24 +97,20 @@ static void page_table_check_clear(unsigned long pfn, unsigned long pgcnt) static void page_table_check_set(unsigned long pfn, unsigned long pgcnt, bool rw) { + struct page_ext_iter iter; struct page_ext *page_ext; struct page *page; - unsigned long i; bool anon; if (!pfn_valid(pfn)) return; page = pfn_to_page(pfn); - page_ext = page_ext_get(page); - - if (!page_ext) - return; - BUG_ON(PageSlab(page)); anon = PageAnon(page); - for (i = 0; i < pgcnt; i++) { + rcu_read_lock(); + for_each_page_ext(page, pgcnt, page_ext, iter) { struct page_table_check *ptc = get_page_table_check(page_ext); if (anon) { @@ -129,9 +120,8 @@ static void page_table_check_set(unsigned long pfn, unsigned long pgcnt, BUG_ON(atomic_read(&ptc->anon_map_count)); BUG_ON(atomic_inc_return(&ptc->file_map_count) < 0); } - page_ext = page_ext_next(page_ext); } - page_ext_put(page_ext); + rcu_read_unlock(); } /* @@ -140,24 +130,19 @@ static void page_table_check_set(unsigned long pfn, unsigned long pgcnt, */ void __page_table_check_zero(struct page *page, unsigned int order) { + struct page_ext_iter iter; struct page_ext *page_ext; - unsigned long i; BUG_ON(PageSlab(page)); - page_ext = page_ext_get(page); - - if (!page_ext) - return; - - for (i = 0; i < (1ul << order); i++) { + rcu_read_lock(); + for_each_page_ext(page, 1 << order, page_ext, iter) { struct page_table_check *ptc = get_page_table_check(page_ext); BUG_ON(atomic_read(&ptc->anon_map_count)); BUG_ON(atomic_read(&ptc->file_map_count)); - page_ext = page_ext_next(page_ext); } - page_ext_put(page_ext); + rcu_read_unlock(); } void __page_table_check_pte_clear(struct mm_struct *mm, pte_t pte)