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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1774577748; 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=Y5PgiQrcwbn9XAgL4cRYPHYRVIr8zaspEnc9S8fZNtw=; b=PBqsuNksqiYxLcyifzHiiquL6Zzzi+Q6QhZKvMqsl6Ywk8e+CwDNj9TY+ZBrYzU5TX4YZX tN7zZsn84kggt2lWPGZqKW8iUu8t1aNBnigvnGagmSkB+xzT/lcMTAqVdArQiFTX42gjln p/GMbq4RVKzlqVsGNHcXNmutrl2WTFQ= From: Usama Arif To: Andrew Morton , david@kernel.org, Lorenzo Stoakes , 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: [v3 16/24] mm: huge_mm: Make sure all split_huge_pmd calls are checked Date: Thu, 26 Mar 2026 19:08:58 -0700 Message-ID: <20260327021403.214713-17-usama.arif@linux.dev> In-Reply-To: <20260327021403.214713-1-usama.arif@linux.dev> References: <20260327021403.214713-1-usama.arif@linux.dev> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 47F9C20002 X-Stat-Signature: qz5z5ky4hq11hdurr5eok8xgmw6i4x33 X-HE-Tag: 1774577749-443068 X-HE-Meta: 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 ETIivA6N oZObRRRxMDRBoYOrSrbWjfH5aQV5+o5ifDpLSg/V3Ivbls0UGeVCvPMg6X5ZdFl1nl9FoQvTPb2H6DYGUGoaS0dmaftqyojE924S2PX6oxc++fGzbKgC6OY6FYT7F1ouCPbQTbLzAvL0K6LOykAcHrGr/2PLbwpOjCp3LIw20zvzA0fdfXAYB4Dye7bcfh+z6e2t9hwb9RPJo/7Pa71hXiygDtpHww9K1IqrrEx7TtYd9rIzMikyN1G5FTg== 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 224965fce4e66..c4d0badc4ce27 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -418,7 +418,7 @@ static inline int split_huge_page(struct page *page) extern struct list_lru deferred_split_lru; void deferred_split_folio(struct folio *folio, bool partially_mapped); -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); /** @@ -447,7 +447,7 @@ 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)) @@ -455,7 +455,7 @@ 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, -- 2.52.0