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[221.241.217.81]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-394f818030asm1031982a91.3.2026.08.14.15.29.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 14 Aug 2026 15:29:06 -0700 (PDT) Date: Sat, 15 Aug 2026 07:29:04 +0900 Message-ID: From: Hajime Tazaki To: ljs@kernel.org Cc: linux-mm@kvack.org, geert@linux-m68k.org, daniel@thingy.jp, akpm@linux-foundation.org, liam@infradead.org, vbabka@kernel.org, jannh@google.com, pfalcato@suse.de Subject: Re: [RFC PATCH 2/6] mm: nommu: use vma_is_anonymous() to check if vmas are anonymous In-Reply-To: References: <20260813063401.1786548-1-thehajime@gmail.com> <20260813063401.1786548-3-thehajime@gmail.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/27.2 Mule/6.0 MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-Stat-Signature: jaxnpqetpkgfpusztb3su9yyuzfqoust X-Rspamd-Queue-Id: 5B01C4000C X-Rspamd-Server: rspam03 X-Rspam-User: X-HE-Tag: 1786746550-891200 X-HE-Meta: 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 qoLlzcGa xtMRD578CwuGdA6lFtyQGkPYOUQZK5RM/QcyrKFEuzkmw63pZMemC9y+Fc1cggspUkRhVSFbwfP5Gjrkkbe6W6UXhzDvutmWkgk/Ej8MF3oeT7Sz8j5c3Txhr2v8TdPGQPhD7FbcIH1dtJhM5aW0IagMX2EdLB3x1wTfMVk+GchJb3RYFVERBgSd0f7ZXkt75KcZ9YXcYHDOL7rdGFor2cHvPfo22Yy3+Or51r2aimoQ5R4EzUuDMWwcUd+XlUl8iBoMuyqpJ+LETkSWIRNOROXbNgxQ1JOSQkGcLvFTlbJpcGRWnVZX44OCTCPwV1ZQXRRolafc1LOa56P60/33x/CDhwZxeoavrXjKlA0eh+UD3pKw0YxMG/Ujeb5G8ojv0kfKa1c2HcjtoHECoKpBzjTaufw== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Fri, 14 Aug 2026 20:52:42 +0900, Lorenzo Stoakes (ARM) wrote: > > On Thu, Aug 13, 2026 at 03:33:57PM +0900, Hajime Tazaki wrote: > > Private file mappings (like those from /dev/zero) can have vma->vm_file > > set but remain structurally anonymous since they lack vm_ops. Testing > > vma->vm_file instead of vma_is_anonymous(vma) might cause mremap to > > return a spurious -EINVAL when userspace attempts to shrink these > > mappings. > > > > This commit fixes this issue by using vma_is_anonymous() instead of > > testing vma->vm_file to address the case of /dev/zero. (snip) > > As staged in review on 1/6 you need to squash this somehow. I see, thanks for point this out. -- Hajime