From nobody Fri Dec 19 09:13:29 2025 Received: from m16.mail.163.com (m16.mail.163.com [220.197.31.5]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 7304313BC35; Tue, 18 Feb 2025 02:52:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=220.197.31.5 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739847153; cv=none; b=hbA3J2YWNPzfbGjuwspD/spo1Rv7qzCLGFI8i3VfHxuxny8+m97eTgn9InxDrXDOJbWfwSBOKTfliOpFKsJEDsKtbvk8tqI+4lfCK0SAb5aAu7/OUJk5KWgeys40n7P8XW8FLjiWq++xmaj55Wd2a50o5UWuJF7Q2LgJuhpgS9g= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1739847153; c=relaxed/simple; bh=PWHofPdlpUwGUnc4/kTVRwpJM2awBxl5+OMElxXC2qk=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=sOlxB6CfLo/573LwbOvlvivbpI8frmPNIJofGszs8NbNy3xbVJ76hEFrMkL906RxVHcxrI65JCAWQtnw/w375ngV16yusggygnA/3rqEg8NoqeKJoB391+KqDI9KFbcwRe3IlKCo58kbrVfwbKHPvtSkvFKectCpTtFMbJLkaXo= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=V27KFIIx; arc=none smtp.client-ip=220.197.31.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="V27KFIIx" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=HMfjP 3H+w2jYqpSYoxGCZQMFuo04FYmpgP9iP4Vdo6s=; b=V27KFIIxsfhw6UP4wxIHH NactfnX++wuOeINRRakHEuCPZRf0CGhv4g9tkp9BMWf74s/BBXipzw3nSIEwtmwU 0bp5FJgvTX5OtglSIrpUmKJM/CrheIPfAKTANKv4siJhXycC3zwShdqNJ/yk9d4v 7dKFlspMwDK6KnOWWtjOO0= Received: from icess-ProLiant-DL380-Gen10.. (unknown []) by gzga-smtp-mtada-g1-3 (Coremail) with SMTP id _____wDn85zi9bNnu4TUMw--.38146S4; Tue, 18 Feb 2025 10:52:19 +0800 (CST) From: Haoxiang Li To: hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, haoxiang_li2024@163.com, schwidefsky@de.ibm.com Cc: linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH v2] s390/sclp: Add check for get_zeroed_page() Date: Tue, 18 Feb 2025 10:52:16 +0800 Message-Id: <20250218025216.2421548-1-haoxiang_li2024@163.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wDn85zi9bNnu4TUMw--.38146S4 X-Coremail-Antispam: 1Uf129KBjvJXoW7Cr1UJF1fCr47Cr1rJw1UKFg_yoW8CF17pF s8Gr4Ykan8Ja9xAFy3J3ZrCayrWw48KrWUtayxAwnxXF13GrWIya47ta4rZFW5Kr18Jay3 JFWjyF13GF4DW37anT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x0pimhF7UUUUU= X-CM-SenderInfo: xkdr5xpdqjszblsqjki6rwjhhfrp/1tbiqRz3bmez7+a-ggAAsM Content-Type: text/plain; charset="utf-8" Add check for the return value of get_zeroed_page() in sclp_console_init() to prevent null pointer dereference. Furthermore, to solve the memory leak caused by the loop allocation, add a free helper to do the free job. Fixes: 4c8f4794b61e ("[S390] sclp console: convert from bootmem to slab") Cc: stable@vger.kernel.org Signed-off-by: Haoxiang Li Acked-by: Heiko Carstens --- Changes in v2: - Add a free helper to solve the memory leak caused by loop allocation. - Thanks Heiko! I realized that v1 patch overlooked a potential memory leak. After consideration, I choose to do the full exercise. I noticed a similar handling in [1], following that handling I submit this v2 patch. Thanks aga= in! Reference link: [1]https://github.com/torvalds/linux/blob/master/drivers/s390/char/sclp_vt2= 20.c#L699 --- drivers/s390/char/sclp_con.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/drivers/s390/char/sclp_con.c b/drivers/s390/char/sclp_con.c index e5d947c763ea..c87b0c204718 100644 --- a/drivers/s390/char/sclp_con.c +++ b/drivers/s390/char/sclp_con.c @@ -263,6 +263,19 @@ static struct console sclp_console =3D .index =3D 0 /* ttyS0 */ }; =20 +/* + * Release allocated pages. + */ +static void __init __sclp_console_free_pages(void) +{ + struct list_head *page, *p; + + list_for_each_safe(page, p, &sclp_con_pages) { + list_del(page); + free_page((unsigned long) page); + } +} + /* * called by console_init() in drivers/char/tty_io.c at boot-time. */ @@ -282,6 +295,10 @@ sclp_console_init(void) /* Allocate pages for output buffering */ for (i =3D 0; i < sclp_console_pages; i++) { page =3D (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA); + if (!page) { + __sclp_console_free_pages(); + return -ENOMEM; + } list_add_tail(page, &sclp_con_pages); } sclp_conbuf =3D NULL; --=20 2.25.1