From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C497C35274 for ; Thu, 21 Dec 2023 12:09:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F313B8D000C; Thu, 21 Dec 2023 07:09:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id EBA358D0001; Thu, 21 Dec 2023 07:09:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D5AD28D000C; Thu, 21 Dec 2023 07:09:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id C6AAE8D0001 for ; Thu, 21 Dec 2023 07:09:56 -0500 (EST) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay09.hostedemail.com (Postfix) with ESMTP id 8D52280DF5 for ; Thu, 21 Dec 2023 12:09:56 +0000 (UTC) X-FDA: 81590706792.27.D198178 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by imf19.hostedemail.com (Postfix) with ESMTP id 14F651A0023 for ; Thu, 21 Dec 2023 12:09:53 +0000 (UTC) Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=ellerman.id.au header.s=201909 header.b="UXZ/8iFV"; spf=pass (imf19.hostedemail.com: domain of mpe@ellerman.id.au designates 150.107.74.76 as permitted sender) smtp.mailfrom=mpe@ellerman.id.au; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1703160595; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=HNgAHhgASKG5cC6HA2RaRQqlTLp7bCesqBG34hJxbJ8=; b=XP8w3dttfHuvtjoGZk1ZuS9+WFNFvmSO3hfakmsoVl2bHh9fZ9bEx7vL6UEe+9AID8mpRp gB28JYrm+/pZgnAP7LkidbN6WyIbQRyTJPNH2yOOm5YWnBcqxP5Vr0IM4NXdGZ6fCw6t7S LyxWxqVkCvkQrv+YxVqE3NWMZBvR174= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1703160595; a=rsa-sha256; cv=none; b=Ys//K49l9Da8BNE/ejK2pFb8mF1R+sXFggmY4e+/tLBftyTNFATGdV+k/W/l6UnJEhEcK5 fDKWVY3o+3MlLpDLDgYYYgjUgNBtn3p6KsnDor3ghJHNqBhzrOMVHxI4fHqNxmVUKrb6Gp de56Adoz3T52URTOjiwPZ0wkuBwG9B8= ARC-Authentication-Results: i=1; imf19.hostedemail.com; dkim=pass header.d=ellerman.id.au header.s=201909 header.b="UXZ/8iFV"; spf=pass (imf19.hostedemail.com: domain of mpe@ellerman.id.au designates 150.107.74.76 as permitted sender) smtp.mailfrom=mpe@ellerman.id.au; dmarc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1703160590; bh=HNgAHhgASKG5cC6HA2RaRQqlTLp7bCesqBG34hJxbJ8=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=UXZ/8iFVFD0RXlNf75DnRzeZjZNqxXdyWlv4k0Hzlfir+cyDg6bzbTkZMQcPEURyP dkTVRxehX5RuNr+aZND8OtKcWszFbK6k8UWIfrAKKvTgU9KtM25R6X2RYV/TGCXe6F dv3/5yh5p0aHNYb1dftrqTuQJW3EQkuse3SZQhoQ3nerzOI/8Hr7sc9fVzUv2thna5 5bnMvnqnCaA1nr0WKnr8U1Ey0AxGM5PNK0A7spgyNi6bRYwkuTIqnw5sBIKTD0uOM9 mYBPuNRUGXdrNxN4h69hABS+DC8IOmVR3y0cPrdjoAD+ad6Soy4Sk6Z1YFgCc0rcmP OL68MK1PQoxAQ== Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (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) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4Swq4G3W56z4xCg; Thu, 21 Dec 2023 23:09:50 +1100 (AEDT) From: Michael Ellerman To: Christophe Leroy , Nicholas Miehlbradt , "glider@google.com" , "elver@google.com" , "dvyukov@google.com" , "akpm@linux-foundation.org" , "npiggin@gmail.com" Cc: "linux-mm@kvack.org" , "kasan-dev@googlegroups.com" , "iii@linux.ibm.com" , "linuxppc-dev@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 02/13] hvc: Fix use of uninitialized array in udbg_hvc_putc In-Reply-To: References: <20231214055539.9420-1-nicholas@linux.ibm.com> <20231214055539.9420-3-nicholas@linux.ibm.com> Date: Thu, 21 Dec 2023 23:09:49 +1100 Message-ID: <87frzvlpte.fsf@mail.lhotse> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Stat-Signature: xc6cpugbw4tbjezf6xu3ggiiyeuuzdyg X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 14F651A0023 X-Rspam-User: X-HE-Tag: 1703160593-534468 X-HE-Meta: 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 vbJSP39q 0iDLcZUuWkKFkNVH6UM8uoL2kpDjoCN5I8Q6lQJgtY9WrypMSyJqV+AWPCpCFNJwdp1LU16JnYKis2PZj+ICFMyoOrQrPXjkgsL5EWqEr2IGi8vRojExGVATW5N4M+VvyOGaHlXwpcGym+9qbPwq4cXqghasAxRzVNX+eulEix4S3eDeeetHTzA5/uSPjgnhFHpoBMIau0MJG6uG/yfHgXnJ8kY0qTfu38fWCZPDxJonjJRrMTtbRuXzFGs5TrQLk4yK3ki/a8iHM71szYgEPcAJaey45hxoGySQywHSOOgBefPFUTq0vTZVOfg== 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: List-Subscribe: List-Unsubscribe: Christophe Leroy writes: > Le 14/12/2023 =C3=A0 06:55, Nicholas Miehlbradt a =C3=A9crit=C2=A0: >> All elements of bounce_buffer are eventually read and passed to the >> hypervisor so it should probably be fully initialized. > > should or shall ? > >>=20 >> Signed-off-by: Nicholas Miehlbradt > > Should be a Fixed: tag ? > >> --- >> drivers/tty/hvc/hvc_vio.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >>=20 >> diff --git a/drivers/tty/hvc/hvc_vio.c b/drivers/tty/hvc/hvc_vio.c >> index 736b230f5ec0..1e88bfcdde20 100644 >> --- a/drivers/tty/hvc/hvc_vio.c >> +++ b/drivers/tty/hvc/hvc_vio.c >> @@ -227,7 +227,7 @@ static const struct hv_ops hvterm_hvsi_ops =3D { >> static void udbg_hvc_putc(char c) >> { >> int count =3D -1; >> - unsigned char bounce_buffer[16]; >> + unsigned char bounce_buffer[16] =3D { 0 }; > > Why 16 while we have a count of 1 in the call to hvterm_raw_put_chars() ? Because hvterm_raw_put_chars() calls hvc_put_chars() which requires a 16 byte buffer, because it passes the buffer directly to firmware which expects a 16 byte buffer. It's a pretty horrible calling convention, but I guess it's to avoid needing another bounce buffer inside hvc_put_chars(). We should probably do the change below, to at least document the interface better. cheers diff --git a/arch/powerpc/include/asm/hvconsole.h b/arch/powerpc/include/as= m/hvconsole.h index ccb2034506f0..0ee7ed019e23 100644 --- a/arch/powerpc/include/asm/hvconsole.h +++ b/arch/powerpc/include/asm/hvconsole.h @@ -22,7 +22,7 @@ * parm is included to conform to put_chars() function pointer template */ extern int hvc_get_chars(uint32_t vtermno, char *buf, int count); -extern int hvc_put_chars(uint32_t vtermno, const char *buf, int count); +extern int hvc_put_chars(uint32_t vtermno, const char buf[16], int count); /* Provided by HVC VIO */ void hvc_vio_init_early(void); diff --git a/arch/powerpc/platforms/pseries/hvconsole.c b/arch/powerpc/plat= forms/pseries/hvconsole.c index 1ac52963e08b..c40a82e49d59 100644 --- a/arch/powerpc/platforms/pseries/hvconsole.c +++ b/arch/powerpc/platforms/pseries/hvconsole.c @@ -52,7 +52,7 @@ EXPORT_SYMBOL(hvc_get_chars); * firmware. Must be at least 16 bytes, even if count is less than 16. * @count: Send this number of characters. */ -int hvc_put_chars(uint32_t vtermno, const char *buf, int count) +int hvc_put_chars(uint32_t vtermno, const char buf[16], int count) { unsigned long *lbuf =3D (unsigned long *) buf; long ret; diff --git a/drivers/tty/hvc/hvc_vio.c b/drivers/tty/hvc/hvc_vio.c index 736b230f5ec0..011b239a7e52 100644 --- a/drivers/tty/hvc/hvc_vio.c +++ b/drivers/tty/hvc/hvc_vio.c @@ -115,7 +115,7 @@ static int hvterm_raw_get_chars(uint32_t vtermno, char = *buf, int count) * you are sending fewer chars. * @count: number of chars to send. */ -static int hvterm_raw_put_chars(uint32_t vtermno, const char *buf, int cou= nt) +static int hvterm_raw_put_chars(uint32_t vtermno, const char buf[16], int = count) { struct hvterm_priv *pv =3D hvterm_privs[vtermno];