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([157.82.204.253]) by smtp.gmail.com with ESMTPSA id jb22-20020a170903259600b001b89466a5f4sm7883559plb.105.2023.07.31.01.03.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 31 Jul 2023 01:03:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=daynix-com.20221208.gappssmtp.com; s=20221208; t=1690790616; x=1691395416; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=YOp4AdoD8Bkg7odyELEU2opCXFUALl4I3whyZmG1z+k=; b=dwR66dtxXEOvdgQUON0x5rThkA5uIRjdmLQuLz+5V7cu5lXxAQLc8DCYYIPoOA6sCK GVgwRbg5xQvwRi2RtbUttZJ8dDTzQkL/bcs3i3QW4l0oYr8WOR9fQKOAWe1+du28+Hat Co5W7Bco3E2Ys+ZedEPOtssEFOul5QiQ1vHd4EIBJEGmhunQYw5wWWH0RR7ZJsWpmvlp 2bw+WPuH5fD9h9huC6WgCG0FjQcTnPJGaBAD99H6Pz7H9NGk3zbfQk9KnBYssDeA0vQw 2+eSSgg6NmTkd/r6t89FvN7qi+b3VD3M+hLQ/Z1tDZGEU/Mqh1z6ybkpf+mvPrLj0200 hrIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690790616; x=1691395416; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=YOp4AdoD8Bkg7odyELEU2opCXFUALl4I3whyZmG1z+k=; b=KI5sbgUlo6hfPHz1F0MCLsQz0IpQ92hIMz7Li7poHC06zqbXzBv947cdPQk2E4tPN1 /hkkh9UtesMOpsKuO81WLu6oZI8MGHefjQKwcJzLz2PbcuTiurrMElD6xPSPtrUjsc7k 2i7UakqDMD/XQyGN+j0h+s76e6hLxbPeMCY8bc/b8P4eHFYZuD5yN4bHCoWEt6mW+X1r n37Vgwe9opBuyvHWdvHPrnyRypERg4NenzrsUPd99fhVhMT/PKZJJGS124nt8UkiXB7Q CHzan9UZo83TW2JAI++MSqMVHdMxT5M39r8t1znrCwGGQklDOTA8RtWWiFCJy5WYzi9d fw3w== X-Gm-Message-State: ABy/qLav397eD/QD0ppW9C3w/bd5T/fb6NAm/Nw3D7fJKsAxvx+j/6RJ +oUsHr0zoTj3tbVYLi8mbm1gIRbSdDhyNVbXjKI= X-Google-Smtp-Source: APBJJlHTRunyYGiU770e+tpFDx8VgoB8ZdLrtZtbWSlP7NR33vVpz8Y8vbZfjUrmMOyykwz2ZuAa7A== X-Received: by 2002:a17:902:d303:b0:1b8:3dec:48de with SMTP id b3-20020a170902d30300b001b83dec48demr8485591plc.47.1690790616157; Mon, 31 Jul 2023 01:03:36 -0700 (PDT) From: Akihiko Odaki To: Cc: qemu-devel@nongnu.org, Laurent Vivier , Akihiko Odaki Subject: [PATCH 3/5] linux-user: Use MAP_FIXED_NOREPLACE for do_brk() Date: Mon, 31 Jul 2023 17:03:12 +0900 Message-ID: <20230731080317.112658-4-akihiko.odaki@daynix.com> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230731080317.112658-1-akihiko.odaki@daynix.com> References: <20230731080317.112658-1-akihiko.odaki@daynix.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: none client-ip=2607:f8b0:4864:20::62e; envelope-from=akihiko.odaki@daynix.com; helo=mail-pl1-x62e.google.com X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_NONE=0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @daynix-com.20221208.gappssmtp.com) X-ZM-MESSAGEID: 1690790670270100001 Content-Type: text/plain; charset="utf-8" MAP_FIXED_NOREPLACE can ensure the mapped address is fixed without concerning that the new mapping overwrites something else. Signed-off-by: Akihiko Odaki --- linux-user/syscall.c | 17 +++-------------- 1 file changed, 3 insertions(+), 14 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index b9d2ec02f9..ac429a185a 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -854,17 +854,12 @@ abi_long do_brk(abi_ulong brk_val) return target_brk; } =20 - /* We need to allocate more memory after the brk... Note that - * we don't use MAP_FIXED because that will map over the top of - * any existing mapping (like the one with the host libc or qemu - * itself); instead we treat "mapped but at wrong address" as - * a failure and unmap again. - */ if (new_host_brk_page > brk_page) { new_alloc_size =3D new_host_brk_page - brk_page; mapped_addr =3D target_mmap(brk_page, new_alloc_size, - PROT_READ|PROT_WRITE, - MAP_ANON|MAP_PRIVATE, 0, 0); + PROT_READ | PROT_WRITE, + MAP_FIXED_NOREPLACE | MAP_ANON | MAP_PRI= VATE, + 0, 0); } else { new_alloc_size =3D 0; mapped_addr =3D brk_page; @@ -883,12 +878,6 @@ abi_long do_brk(abi_ulong brk_val) target_brk =3D brk_val; brk_page =3D new_host_brk_page; return target_brk; - } else if (mapped_addr !=3D -1) { - /* Mapped but at wrong address, meaning there wasn't actually - * enough space for this brk. - */ - target_munmap(mapped_addr, new_alloc_size); - mapped_addr =3D -1; } =20 #if defined(TARGET_ALPHA) --=20 2.41.0