From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 93480CD5BC8 for ; Tue, 26 May 2026 13:11:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D203E6B00E0; Tue, 26 May 2026 09:11:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CF7F66B00E1; Tue, 26 May 2026 09:11:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C34A26B00E2; Tue, 26 May 2026 09:11:16 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id B2E8F6B00E0 for ; Tue, 26 May 2026 09:11:16 -0400 (EDT) Received: from smtpin03.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 54AE1161664 for ; Tue, 26 May 2026 13:11:16 +0000 (UTC) X-FDA: 84809606952.03.F8D7F6E Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf26.hostedemail.com (Postfix) with ESMTP id BD4AD140011 for ; Tue, 26 May 2026 13:11:14 +0000 (UTC) Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=f11GtvcZ; spf=pass (imf26.hostedemail.com: domain of osalvador@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=osalvador@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1779801074; a=rsa-sha256; cv=none; b=dS233l/ze8/1+h74FPSjNct0/qdRj0Hno5dDAiAvtp2ly9gkXq0JvjnW3f7q7pGPLtnC7z 9sph33UYZBaYSXcE+VkFHwH4b5Ird0mD74rvtxxPOEydssFnE3DhpE1H1BonlA0r5Hdrch MLchv+DXLVIS70EZo3ZTOxyvu5hKIs0= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=f11GtvcZ; spf=pass (imf26.hostedemail.com: domain of osalvador@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=osalvador@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1779801074; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=NLRxZs5V+Xs9xqYGiEg8hW6pN2SYk32SRlLoQ0q4z48=; b=QJ7gHuqiuqAIAFXjdhLi6ahwwTaVt1TD743oIZOOcB/8sAWeRV6UsNgNIj+Dlnmjnm4E3u cG2sk0nOcTf7Htni5jTMWjHn/hygdvcx48vGT1liHADZj5kO9HOsOQQRLV1IF47/NPM4o5 nYzKj9rSwW3hqo2pw1kzkpharOTNBwY= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 4D6D260236; Tue, 26 May 2026 13:11:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id ACB1B1F000E9; Tue, 26 May 2026 13:11:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1779801074; bh=NLRxZs5V+Xs9xqYGiEg8hW6pN2SYk32SRlLoQ0q4z48=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=f11GtvcZxkf03mTF0kMhig0MOy+SLr4+uLQnFm3aMunR1kizOq/vSLNl0quYjWDYP jneHF/5xyTIH+DCM8AqXkxvlnYdixmvb9DIXneSc53uw+3UoTQnaVrJmOyA5Y1PVey G8yGtmd2UeTthx19hW8bkKGOWtuvnrE9tJ2jvFGtSqzuwugZVc+SCkfpPnscLpJ6V6 GPDyGyhvYBPyAaU/kv+VePggfepTr9Xkc3JJ4f5Nskg8xy171w3psMX73pvWa01fJQ DwvilQDlg64atNguzsAV8G++XdKGr/LPObLmau77BGZdbhX1hH5R9Viz6rh9QrZWq3 xwPkXKCXNG2yA== Date: Tue, 26 May 2026 15:11:07 +0200 From: "Oscar Salvador (SUSE)" To: Muchun Song Cc: Andrew Morton , David Hildenbrand , linux-mm@kvack.org, Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Frank van der Linden , linux-kernel@vger.kernel.org, stable@vger.kernel.org, muchun.song@linux.dev Subject: Re: [PATCH v2] mm/cma: fix reserved page leak on activation failure Message-ID: References: <20260523060123.2207992-1-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260523060123.2207992-1-songmuchun@bytedance.com> X-Rspam-User: X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: BD4AD140011 X-Stat-Signature: nu91jr6p4bce1po7m18ektjwnn3n7aok X-HE-Tag: 1779801074-534361 X-HE-Meta: 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 tIH41+Q+ Kbw8VmqIK3myTWmzBHNMvqe4UGFhKn4LQGXhXCblHnuR3a/aIOqs7D5dpqb6YIFSpBxkpYEAAqX2UI4hsLwiff5cnTFagrrV7zl0rDHk7mVhhD7BwYuni5IuqoyCkZshemQQ8qmmJea8iWxn0sn4ub3hZR4Db7ULAsc4vjr05PURXg/Fo9uyLzBQDyMOWSUnRD5h4kYen6wtmU7qwZcVyp9OGOK828naTd8j3+Zpqh3pAagCTa0gh09cs0Cf+AxxKqAGg Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Sat, May 23, 2026 at 02:01:23PM +0800, Muchun Song wrote: > If cma_activate_area() fails after allocating only part of the range > bitmaps, the cleanup path still has to release the reserved pages when > CMA_RESERVE_PAGES_ON_ERROR is clear. > > That is still worth doing even in this __init path. A bitmap_zalloc() > failure does not necessarily mean the system cannot make further progress: > freeing the reserved CMA pages can return a substantial amount of memory > to the buddy allocator and may relieve the temporary memory shortage that > caused the allocation failure in the first place. > > However, the cleanup path currently uses the bitmap-freeing bound for page > release as well. That is only correct for ranges whose bitmap allocation > already succeeded. The failed range and all later ranges still keep their > reserved pages, so a partial bitmap allocation failure can permanently > leak them. > > Fix this by releasing reserved pages for all ranges. Use the saved > early_pfn[] value for ranges whose bitmap allocation already succeeded and > for the failed range, and use cmr->early_pfn for later ranges whose bitmap > allocation was never attempted. > > Fixes: c009da4258f9 ("mm, cma: support multiple contiguous ranges, if requested") > Cc: stable@vger.kernel.org > Signed-off-by: Muchun Song Reviewed-by: Oscar Salvador (SUSE) -- Oscar Salvador SUSE Labs