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([2602:47:d490:6901:1eed:f77f:f320:8b14]) by smtp.gmail.com with ESMTPSA id u1-20020a17090282c100b001bbf7fd354csm2185568plz.213.2023.08.04.15.00.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 04 Aug 2023 15:00:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1691186441; x=1691791241; 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=U8M/sECGKblXQECxwhiXY/mNUP2fHciHERdH2OiT8nA=; b=URbVDpZtOGNC5hpJterst+zcn+LmZ0H52ajLs5rR4C/g3FML0E36w5LGt9LS3t6zRr OwVQiiVwZgEp4fnP5fEYWsLpdUnOn9oqOjx1mLF91Y4DJpTPDMorngourzXdFBNw9TWC 2v00IxMjimraHuEyAfbEz2RxmTwCwynMTfEgLXLsbw4pC4EOb1NQGbfaSgQOCMGtdlym aoecHlSiVxYUZHIfpBZkcF1XyhhLFgaDir+dmqJoStxIVHYK66TDvnB12i29GgVD1l2d 1jxv29FpOEjolI3L4fux2md6rGCb4BgAF5un+EOYeyNI0mXLjRyHfi2PKn4OhCZl7KXo P2RA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1691186441; x=1691791241; 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=U8M/sECGKblXQECxwhiXY/mNUP2fHciHERdH2OiT8nA=; b=V5rMzB3AZNHxKvFhhZKskgFSnS75aMkqkZNBlINqNL1sm7tATUGyHM1C9WpgBAbA++ OQ14hWI3AW+nsTMNxbACuekrGyRhJtnjQK3bZyhLySdg9QclRKAhAb2VzSfjp1uSapUt YmCJRl/LkINTAauMPOxTGAYn98nJWtlNu+5ppzy9sjdvi6H8kzilH9Myn5CXJVVXDcId CUQwLmvLAHc7PqFmN4rqJy8ckCI29MRBfF7sUXpGQHD74AFMonynriNMqOpRa7QNWe4s ETQAY8NCn05J87OjzKIHpepu7VQ6+wHVffd0FhDyuMRWrqnU5gJ9h+PT6gKrBlVdrUL+ oE+w== X-Gm-Message-State: AOJu0YwsEV7id3Yg/bA1DI+w2Wjx++qyDPbqdh3WQ8ZyyXUE5zaB6qqG 25PcytcGybAGfgMYbn6X0Iwr1wNhLOxXP5y2HYI= X-Google-Smtp-Source: AGHT+IG+KHBw+Kd5NUx4rZ/Y+snEUDfpH17SVvs+iCiI3iZeo+1Fwt48fD2BK8zOCqebdTNrzE7upA== X-Received: by 2002:a17:902:ea91:b0:1b8:b442:aa97 with SMTP id x17-20020a170902ea9100b001b8b442aa97mr2824551plb.54.1691186440849; Fri, 04 Aug 2023 15:00:40 -0700 (PDT) From: Richard Henderson To: qemu-devel@nongnu.org Cc: Akihiko Odaki Subject: [PATCH v9 08/24] linux-user: Use MAP_FIXED_NOREPLACE for do_brk() Date: Fri, 4 Aug 2023 15:00:16 -0700 Message-Id: <20230804220032.295411-9-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230804220032.295411-1-richard.henderson@linaro.org> References: <20230804220032.295411-1-richard.henderson@linaro.org> 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: pass client-ip=2607:f8b0:4864:20::634; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x634.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 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 @linaro.org) X-ZM-MESSAGEID: 1691186527698100002 Content-Type: text/plain; charset="utf-8" From: Akihiko Odaki MAP_FIXED_NOREPLACE can ensure the mapped address is fixed without concerning that the new mapping overwrites something else. Signed-off-by: Akihiko Odaki Message-Id: <20230802071754.14876-5-akihiko.odaki@daynix.com> [rth: Pass -1 as fd for MAP_ANON] Reviewed-by: Richard Henderson Signed-off-by: Richard Henderson --- 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..f64024273f 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, + -1, 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 2.34.1