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 92D03FC5933 for ; Thu, 26 Feb 2026 11:34:17 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 057676B00AA; Thu, 26 Feb 2026 06:34:17 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 00AD26B00AD; Thu, 26 Feb 2026 06:34:16 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E70316B00AE; Thu, 26 Feb 2026 06:34:16 -0500 (EST) 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 D0ABD6B00AA for ; Thu, 26 Feb 2026 06:34:16 -0500 (EST) Received: from smtpin18.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 918031B7B81 for ; Thu, 26 Feb 2026 11:34:16 +0000 (UTC) X-FDA: 84486399312.18.4D6C96E Received: from out-172.mta0.migadu.com (out-172.mta0.migadu.com [91.218.175.172]) by imf24.hostedemail.com (Postfix) with ESMTP id DA39B180006 for ; Thu, 26 Feb 2026 11:34:13 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=WE+bzrYN; spf=pass (imf24.hostedemail.com: domain of usama.arif@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=usama.arif@linux.dev; dmarc=pass (policy=none) header.from=linux.dev ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1772105654; 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-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=S0H8ygH+YlO4CNCx03qcK3DVZPCm8qVQiV1k1Y2d+/k=; b=gpRn33GdVr566IykVhCSCXfM9TOmym7tY7mXgKDwajVvP41ULxD148Rt5DmE7yVGYDcmPp iWqMOD5BMUNNW1dS+/k66FAqFdZKtgPuFrNpAihDqCZ8v4bJ9Hn2v0shOGBlKX+Watm6VZ 3bYOdNH00eSpzpFHsWA/lqljaexz/ko= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1772105654; a=rsa-sha256; cv=none; b=lzXkeoCwaVIoMP+xwo7bkmHaD16dqTIMweZ3UTP8iiqDmItzdkVm3RqGyPKrAdMiGWaX5U sUxCbAtP64zyZ7gaWksogrenD0Gs7mX/7uoi7kk2SEO+pboC8MgFgaEzi9cz8xOzhDbbI3 6Ojh9MS9PO64xGbtnL2hZeCu3RCrqTQ= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=linux.dev header.s=key1 header.b=WE+bzrYN; spf=pass (imf24.hostedemail.com: domain of usama.arif@linux.dev designates 91.218.175.172 as permitted sender) smtp.mailfrom=usama.arif@linux.dev; dmarc=pass (policy=none) header.from=linux.dev X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1772105652; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=S0H8ygH+YlO4CNCx03qcK3DVZPCm8qVQiV1k1Y2d+/k=; b=WE+bzrYNxkX7rkOvVYIotj0P/HNDg7dgr5BIyKjoWK6c/gNQyNgdKm5vkjTkfoZRMJ11uG 7YnOvlg6mRw5/v+qJxjjYm2FpSYphCBWmhfAjo9Kp1SB7EoIDR3aW2hScwzOCQc+oLE42l nXUPqt58pVi3eC52uFA6Yk2oOf9BZZA= From: Usama Arif To: Andrew Morton , david@kernel.org, lorenzo.stoakes@oracle.com, willy@infradead.org, linux-mm@kvack.org Cc: fvdl@google.com, hannes@cmpxchg.org, riel@surriel.com, shakeel.butt@linux.dev, kas@kernel.org, baohua@kernel.org, dev.jain@arm.com, baolin.wang@linux.alibaba.com, npache@redhat.com, Liam.Howlett@oracle.com, ryan.roberts@arm.com, Vlastimil Babka , lance.yang@linux.dev, linux-kernel@vger.kernel.org, kernel-team@meta.com, maddy@linux.ibm.com, mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, linux-s390@vger.kernel.org, Usama Arif Subject: [RFC v2 13/21] mm: huge_mm: Make sure all split_huge_pmd calls are checked Date: Thu, 26 Feb 2026 03:23:42 -0800 Message-ID: <20260226113233.3987674-14-usama.arif@linux.dev> In-Reply-To: <20260226113233.3987674-1-usama.arif@linux.dev> References: <20260226113233.3987674-1-usama.arif@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Stat-Signature: 3sjff1gq1akwdcjwb64tm8qk8mjqqws7 X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: DA39B180006 X-HE-Tag: 1772105653-33294 X-HE-Meta: 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 nke7Wil3 f+fXY3MzcF/810o3Q/RBv0rNCkVTw3tv5/bhgxzdfmaxqddcmvU9IAi2fPT/0YKBkTwz/nQ7L+eK37oltv6Rcw1DJYOEnYMKrip+EYiu8LSTF/OcvRaGJsMa1hkbHDI05/uQcexasbGSD2QwbdczaUtGkEljI02eqOwlNY+AujadAxny4fg6lTNpCS3kKTYG9fwcgvgIqGBDqVo8Q9Dhgr4BKJekLZzm+6U4ctXN+eeIe9GDVqJPys4a+kA== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Mark __split_huge_pmd(), split_huge_pmd() and split_huge_pmd_address() with __must_check so the compiler warns if any caller ignores the return value. Not checking return value and operating on the basis that the pmd is split could result in a kernel bug. The possibility of an order-0 allocation failing for page table allocation is very low, but it should be handled correctly. Signed-off-by: Usama Arif --- include/linux/huge_mm.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 207bf7cd95c78..b4c2fd4252097 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -419,7 +419,7 @@ void deferred_split_folio(struct folio *folio, bool partially_mapped); void reparent_deferred_split_queue(struct mem_cgroup *memcg); #endif -int __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, +int __must_check __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long address, bool freeze); /** @@ -448,7 +448,7 @@ static inline bool pmd_is_huge(pmd_t pmd) return false; } -static inline int split_huge_pmd(struct vm_area_struct *vma, +static inline int __must_check split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, unsigned long address) { if (pmd_is_huge(*pmd)) @@ -456,7 +456,7 @@ static inline int split_huge_pmd(struct vm_area_struct *vma, return 0; } -int split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, +int __must_check split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address, bool freeze); void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud, -- 2.47.3