From nobody Sat Jan 15 13:54:31 2022 X-Original-To: standards@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 3E958195EE2A for ; Sat, 15 Jan 2022 13:54:33 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4JbfmR4r5Cz4Vfw for ; Sat, 15 Jan 2022 13:54:31 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org (kenobi.freebsd.org [IPv6:2610:1c1:1:606c::50:1d]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 5B0EA13E for ; Sat, 15 Jan 2022 13:54:31 +0000 (UTC) (envelope-from bugzilla-noreply@freebsd.org) Received: from kenobi.freebsd.org ([127.0.1.5]) by kenobi.freebsd.org (8.15.2/8.15.2) with ESMTP id 20FDsVHN081776 for ; Sat, 15 Jan 2022 13:54:31 GMT (envelope-from bugzilla-noreply@freebsd.org) Received: (from www@localhost) by kenobi.freebsd.org (8.15.2/8.15.2/Submit) id 20FDsV9c081775 for standards@FreeBSD.org; Sat, 15 Jan 2022 13:54:31 GMT (envelope-from bugzilla-noreply@freebsd.org) X-Authentication-Warning: kenobi.freebsd.org: www set sender to bugzilla-noreply@freebsd.org using -f From: bugzilla-noreply@freebsd.org To: standards@FreeBSD.org Subject: [Bug 255072] boot (legacy): no progress beyond 'BIOS DRIVE D: is disk1' Date: Sat, 15 Jan 2022 13:54:31 +0000 X-Bugzilla-Reason: AssignedTo X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: Base System X-Bugzilla-Component: standards X-Bugzilla-Version: Unspecified X-Bugzilla-Keywords: X-Bugzilla-Severity: Affects Some People X-Bugzilla-Who: tsoome@freebsd.org X-Bugzilla-Status: New X-Bugzilla-Resolution: X-Bugzilla-Priority: --- X-Bugzilla-Assigned-To: standards@FreeBSD.org X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Bugzilla-URL: https://bugs.freebsd.org/bugzilla/ Auto-Submitted: auto-generated List-Id: Standards compliance List-Archive: https://lists.freebsd.org/archives/freebsd-standards List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-standards@freebsd.org X-BeenThere: freebsd-standards@freebsd.org MIME-Version: 1.0 ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1642254872; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dRfO2uCzJMR+ypkYtRQnIoRJnikywLWCwzKUVWMJZtg=; b=GrH3hD2zMiR5+6AHAODLMDmY9V90+psdwnRpXn6Z92494Ei5uZ5JEpZheIY2fis930R+jc PlDK1IOMuBm7mRfLHvf0r/DWzcnm2gTOPwhUpPiTtrivZubSxqoJHKhq6fNwyVeb0knrFd Y9bX18YPKcCoa/dGbsr7Wq2cc7jSCgz69ZSkyd02p5y35kuA75gPVuInNAjj5LiSGuxJ/Z sTvFbQGNXiok/sL8k0WrUd/xwgF5Ms0K0soHpnLXVQQuPgIsOZcZaG0dM4W9QmXPYYnLFW wo6j9TAgHF6wYIz3dsxUzm4TMo+OLb0H2N43rB+Lk39tg1knt3na/8wZIVjlTA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1642254872; a=rsa-sha256; cv=none; b=a4FWTFEPbd8Em39M+kojxvqTMdbuWlnBsZDAyMaxo2EtFawuhi7kAvWDm8M6CZGml/Vqje 5tVyZdFCDn3Kb0ehpah0n35R6l5Fn8FwKt4l2xJS73EipyDg53Ki+Sa7g7p1LQWjq7p5BT FM0ma9eu/xGFU3MlV1xMAr8FZQNRqqYY4j/aXINrP+8GBUueQJVLCbUxIypKIvdKCrOOVy +cTabZ5emf2YztKM36xQl3KYHLBI2JcFADioSaMacfGVzvqTRI8CbsSlFr8HcJWXGhzzlb IuwB3jpILgWCzylxlMynaYqu+TKsXu9ONEzAIwUfFikqL0Hdm5132K9Ldm4hLQ== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D255072 --- Comment #30 from Toomas Soome --- (In reply to spell from comment #28) just remind me, what version of freebsd is this, current? the bbuf assignment test is suggesting we do get some sort of buffer overrun there. ok, V86_IO_BUFFER is at 0x8000 and with size 0x1000 (4KB), BIO_BUFFER_SIZE = is 0x4000 (16KB), the buffer is allocated from bss segment (see bio.c bio_buffer[BIO_BUFFER_SIZE]. so, both areas should be safe - in low memory and therefore usable by BIOS = INT calls. Now the catch there is, the btx (our V86 mode "kernel") is at 0x9000, and loader is at 0xA000 (code start, followed by data, bss segments and then stack). So, if the INT will write past 0x8000 + 0x1000, it will corrupt BTX= ; if INT will write past end of bio_buffer, it will corrupt next variable in BSS. So, if you are using IO size 512, then both buffer spaces should be just fi= ne. If the INT call will actually use more of that memory, then we may be in trouble. I guess the only way to detect how much buffer memory was actually used, can be detected by storing know value into entire buffer, and test how big are it is where the buffer is changed. With no buffer overrun, we would expect exactly the IO size to be changed... --=20 You are receiving this mail because: You are the assignee for the bug.=