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[34.150.239.118]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6bb9c839ee1sm59976976d6.89.2024.08.07.14.19.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 07 Aug 2024 14:19:33 -0700 (PDT) From: Pasha Tatashin To: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, cerasuolodomenico@gmail.com, hannes@cmpxchg.org, j.granados@samsung.com, lizhijian@fujitsu.com, muchun.song@linux.dev, nphamcs@gmail.com, pasha.tatashin@soleen.com, rientjes@google.com, rppt@kernel.org, souravpanda@google.com, vbabka@suse.cz, willy@infradead.org Subject: [PATCH v2 1/3] mm: update the memmap stat before page is freed Date: Wed, 7 Aug 2024 21:19:27 +0000 Message-ID: <20240807211929.3433304-2-pasha.tatashin@soleen.com> X-Mailer: git-send-email 2.46.0.76.ge559c4bf1a-goog In-Reply-To: <20240807211929.3433304-1-pasha.tatashin@soleen.com> References: <20240807211929.3433304-1-pasha.tatashin@soleen.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" It is more logical to update the stat before the page is freed, to avoid use after free scenarios. Fixes: 15995a352474 ("mm: report per-page metadata information") Signed-off-by: Pasha Tatashin Reviewed-by: David Hildenbrand --- mm/hugetlb_vmemmap.c | 4 ++-- mm/page_ext.c | 8 ++++---- 2 files changed, 6 insertions(+), 6 deletions(-) diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index 829112b0a914..fa83a7b38199 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -185,11 +185,11 @@ static int vmemmap_remap_range(unsigned long start, u= nsigned long end, static inline void free_vmemmap_page(struct page *page) { if (PageReserved(page)) { - free_bootmem_page(page); mod_node_page_state(page_pgdat(page), NR_MEMMAP_BOOT, -1); + free_bootmem_page(page); } else { - __free_page(page); mod_node_page_state(page_pgdat(page), NR_MEMMAP, -1); + __free_page(page); } } =20 diff --git a/mm/page_ext.c b/mm/page_ext.c index c191e490c401..962d45eee1f8 100644 --- a/mm/page_ext.c +++ b/mm/page_ext.c @@ -330,18 +330,18 @@ static void free_page_ext(void *addr) if (is_vmalloc_addr(addr)) { page =3D vmalloc_to_page(addr); pgdat =3D page_pgdat(page); + mod_node_page_state(pgdat, NR_MEMMAP, + -1L * (DIV_ROUND_UP(table_size, PAGE_SIZE))); vfree(addr); } else { page =3D virt_to_page(addr); pgdat =3D page_pgdat(page); + mod_node_page_state(pgdat, NR_MEMMAP, + -1L * (DIV_ROUND_UP(table_size, PAGE_SIZE))); BUG_ON(PageReserved(page)); kmemleak_free(addr); free_pages_exact(addr, table_size); } - - mod_node_page_state(pgdat, NR_MEMMAP, - -1L * (DIV_ROUND_UP(table_size, PAGE_SIZE))); - } =20 static void __free_page_ext(unsigned long pfn) --=20 2.46.0.76.ge559c4bf1a-goog