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a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=1bhyBo7al6IFmy67jCXlva3rHybPAJSM2yEaUOJQ4lY=; b=pU4iWaqtWjr3wOqliHaLoZFvPqkPHy/iypQrc6IQ8UhnhNTTCkioN3Zw/fFvOk2YS6 fj5ct+edWvTw1Qt1xKXiD6IcruwcZJ7WdMHkHaZsL6/OnqKt5gRurW7/yCkTqZdnZGlO OGsp9DNoAVVyhP5loUGtof2VpMh55GzyF2+vv/oZACkL4Y8yorbVGRf32DccE+HAHwVO AEOdIfIeHaYQcLnpQApZgb3NJj/TCK65JowiwLyuu4pZQwyt4KJK8WObcbzdpzs/8FNQ olSbN9w+ehgfSh8E6qUsEBHfQqj3J4qnXg6/NrkjtrjeVmEuCenv9GAHlvR83/U8bxMT lAZg== X-Gm-Message-State: AFqh2ko5iGrqV6ZkUVBaY7RT4W+1EclgjXch2ZGTO6wUgmrYEO5lVxS/ eqWt7Zp+U4hb5ViQ4EpJ6LBHP4Uc89TYY0XRy4LEHA== X-Google-Smtp-Source: AMrXdXvTA5PhW5zsIFLrGos4xAsLGsOemtNo62tdUEyPmQhzs2vfsnov8+FaF7brmdc4+MYKWjG1pVrfUgIsQlq4xVw= X-Received: by 2002:a25:9801:0:b0:7d5:b884:3617 with SMTP id a1-20020a259801000000b007d5b8843617mr3047541ybo.380.1674694213026; Wed, 25 Jan 2023 16:50:13 -0800 (PST) MIME-Version: 1.0 References: <20230125233554.153109-1-surenb@google.com> <20230125233554.153109-2-surenb@google.com> <20230125162159.a66e5ef05fecb405e85ffec9@linux-foundation.org> In-Reply-To: <20230125162159.a66e5ef05fecb405e85ffec9@linux-foundation.org> From: Suren Baghdasaryan Date: Wed, 25 Jan 2023 16:50:01 -0800 Message-ID: Subject: Re: [PATCH v3 1/7] kernel/fork: convert vma assignment to a memcpy To: Andrew Morton Cc: michel@lespinasse.org, jglisse@google.com, mhocko@suse.com, vbabka@suse.cz, hannes@cmpxchg.org, mgorman@techsingularity.net, dave@stgolabs.net, willy@infradead.org, liam.howlett@oracle.com, peterz@infradead.org, ldufour@linux.ibm.com, paulmck@kernel.org, mingo@redhat.com, will@kernel.org, luto@kernel.org, songliubraving@fb.com, peterx@redhat.com, david@redhat.com, dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de, kent.overstreet@linux.dev, punit.agrawal@bytedance.com, lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com, axelrasmussen@google.com, joelaf@google.com, minchan@google.com, jannh@google.com, shakeelb@google.com, tatashin@google.com, edumazet@google.com, gthelen@google.com, gurua@google.com, arjunroy@google.com, soheil@google.com, hughlynch@google.com, leewalsh@google.com, posk@google.com, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, x86@kernel.org, linux-kernel@vger.kernel.org, kernel-team@android.com Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 2D76414000A X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: ncesww9791jaanji75oreout67gkrwsd X-HE-Tag: 1674694213-780820 X-HE-Meta: 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 A6apAMHt GlHFqTrVAvAfCp+5eWZ3vZhIzVEpk0bzEBAkLxl1JVRZF28MXhVb0ufQipk5Lfp12cUMBf1tfeWYG66YPTGXeWKCmlCGvEtGBpxRnff0R5ywGLe1xvZjahal7WwzudQ9a7x4+h7RJxyzYy19TnGbNyqcHCvzfkZ8BaW/bbMR3JpRdWRpqAgy1mqkS5NFFX6Jyph0APmTmK58l3O3wMIeJ5r4WSuR/+DPWVO8lytkMgwN6ySDC02Iz9R0EqmI0HBUiaFGjIO6PNDOkEmc0RAerFH8M2GJBt4YmvJOUmueMKrGp1Xvhkp4iVcnC4nFWQfYK68M0Oaa0YHkYxwI= 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: On Wed, Jan 25, 2023 at 4:22 PM Andrew Morton wrote: > > On Wed, 25 Jan 2023 15:35:48 -0800 Suren Baghdasaryan wrote: > > > Convert vma assignment in vm_area_dup() to a memcpy() to prevent compiler > > errors when we add a const modifier to vma->vm_flags. > > > > ... > > > > --- a/kernel/fork.c > > +++ b/kernel/fork.c > > @@ -482,7 +482,7 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) > > * orig->shared.rb may be modified concurrently, but the clone > > * will be reinitialized. > > */ > > - *new = data_race(*orig); > > + memcpy(new, orig, sizeof(*new)); > > The data_race() removal is unchangelogged? True. I'll add a note in the changelog about that. Ideally I would like to preserve it but I could not find a way to do that. > > > INIT_LIST_HEAD(&new->anon_vma_chain); > > dup_anon_vma_name(orig, new); > > } >