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[198.145.29.99]) by mx.google.com with ESMTPS id n3si18267438pgk.405.2019.01.28.08.10.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 28 Jan 2019 08:10:44 -0800 (PST) Received-SPF: pass (google.com: domain of sashal@kernel.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=FC+tjslz; spf=pass (google.com: domain of sashal@kernel.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=sashal@kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 8DF8A2084A; Mon, 28 Jan 2019 16:10:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1548691843; bh=iMPET4x1Ri3FMmeFZ87YAw+rJQU9OwKtkcfiyE1nWo8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FC+tjslzyI5EGb9RLk2BMcsJ16icWWiZPVjxrPaypOhQUTQEQD8FCx7QeLTnqmhi4 T4RD5T+kKtrclpPuoFGhSOmlRYGHh90nG1A+dQVvknFB4RO7Uyi2G1nTdhQnuu/lS4 nKHAcgeU4lMQH1K0WqMqpWDiWI1FIh/BYXKUD80Y= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Miles Chen , Joe Perches , Matthew Wilcox , Andrew Morton , Linus Torvalds , Sasha Levin , linux-mm@kvack.org Subject: [PATCH AUTOSEL 4.19 235/258] mm/page_owner: clamp read count to PAGE_SIZE Date: Mon, 28 Jan 2019 10:59:01 -0500 Message-Id: <20190128155924.51521-235-sashal@kernel.org> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190128155924.51521-1-sashal@kernel.org> References: <20190128155924.51521-1-sashal@kernel.org> MIME-Version: 1.0 X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit 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: Content-Type: text/plain; charset="UTF-8" Message-ID: <20190128155901.ldFAbGdyX-I2-oraKjLUmkDMgIARvpwUkUrmPgSsTSA@z> From: Miles Chen [ Upstream commit c8f61cfc871fadfb73ad3eacd64fda457279e911 ] The (root-only) page owner read might allocate a large size of memory with a large read count. Allocation fails can easily occur when doing high order allocations. Clamp buffer size to PAGE_SIZE to avoid arbitrary size allocation and avoid allocation fails due to high order allocation. [akpm@linux-foundation.org: use min_t()] Link: http://lkml.kernel.org/r/1541091607-27402-1-git-send-email-miles.chen@mediatek.com Signed-off-by: Miles Chen Acked-by: Michal Hocko Cc: Joe Perches Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin --- mm/page_owner.c | 1 + 1 file changed, 1 insertion(+) diff --git a/mm/page_owner.c b/mm/page_owner.c index d80adfe702d3..9ad588444671 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -351,6 +351,7 @@ print_page_owner(char __user *buf, size_t count, unsigned long pfn, .skip = 0 }; + count = min_t(size_t, count, PAGE_SIZE); kbuf = kmalloc(count, GFP_KERNEL); if (!kbuf) return -ENOMEM; -- 2.19.1