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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2135DC4167E for ; Wed, 30 Mar 2022 11:54:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344820AbiC3L4g (ORCPT ); Wed, 30 Mar 2022 07:56:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60788 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345966AbiC3LzR (ORCPT ); Wed, 30 Mar 2022 07:55:17 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A70252BB0B; Wed, 30 Mar 2022 04:53:32 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5D358B81C29; Wed, 30 Mar 2022 11:53:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B6B2C340F3; Wed, 30 Mar 2022 11:53:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1648641210; bh=bkZOOo4OTLPt/6iak3xmqexQD+t/tDVRYpkeLEA+SSw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SHXgdjq4LqzfXp3VJV3j29trvrqW8QFtnVDMHATDPTAufV4gWbzk2v30nwLESJLif HlkbNCD4zoKsnQIupCej5g2pR8RuEflgLJvzTCRqessbkz6xgMRHKlcJ4OJvItjwha QRZul2Il/ME3e6FSPR1HsVX+PU01+oO6xKaXdeX2NtOH4aPtggbiq4L79dPlHRxXaa aKioB1M/ok+baZwru2LOZuXUXhHaIPkMgh0rmj4eOBo5yEr/WnXrCbFYRH41RTQkaO U1UyDczcLAmKQDTjcYnnfduq1+2aADB23PmcTawxtK4OKLIJ4UcxW1NJQi5xtWBbi2 maC6lL5Mbx+AA== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Zheyu Ma , Helge Deller , Sasha Levin , sudipm.mukherjee@gmail.com, teddy.wang@siliconmotion.com, tomi.valkeinen@ti.com, linux-fbdev@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 17/22] video: fbdev: sm712fb: Fix crash in smtcfb_write() Date: Wed, 30 Mar 2022 07:52:58 -0400 Message-Id: <20220330115303.1672616-17-sashal@kernel.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220330115303.1672616-1-sashal@kernel.org> References: <20220330115303.1672616-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org From: Zheyu Ma [ Upstream commit 4f01d09b2bbfbcb47b3eb305560a7f4857a32260 ] When the sm712fb driver writes three bytes to the framebuffer, the driver will crash: BUG: unable to handle page fault for address: ffffc90001ffffff RIP: 0010:smtcfb_write+0x454/0x5b0 Call Trace: vfs_write+0x291/0xd60 ? do_sys_openat2+0x27d/0x350 ? __fget_light+0x54/0x340 ksys_write+0xce/0x190 do_syscall_64+0x43/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Fix it by removing the open-coded endianness fixup-code. Signed-off-by: Zheyu Ma Signed-off-by: Helge Deller Signed-off-by: Sasha Levin --- drivers/video/fbdev/sm712fb.c | 21 ++++----------------- 1 file changed, 4 insertions(+), 17 deletions(-) diff --git a/drivers/video/fbdev/sm712fb.c b/drivers/video/fbdev/sm712fb.c index 1781ca697f66..76b1866dfa95 100644 --- a/drivers/video/fbdev/sm712fb.c +++ b/drivers/video/fbdev/sm712fb.c @@ -1130,7 +1130,7 @@ static ssize_t smtcfb_write(struct fb_info *info, const char __user *buf, count = total_size - p; } - buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count, GFP_KERNEL); + buffer = kmalloc(PAGE_SIZE, GFP_KERNEL); if (!buffer) return -ENOMEM; @@ -1148,24 +1148,11 @@ static ssize_t smtcfb_write(struct fb_info *info, const char __user *buf, break; } - for (i = c >> 2; i--;) { - fb_writel(big_swap(*src), dst++); + for (i = (c + 3) >> 2; i--;) { + fb_writel(big_swap(*src), dst); + dst++; src++; } - if (c & 3) { - u8 *src8 = (u8 *)src; - u8 __iomem *dst8 = (u8 __iomem *)dst; - - for (i = c & 3; i--;) { - if (i & 1) { - fb_writeb(*src8++, ++dst8); - } else { - fb_writeb(*src8++, --dst8); - dst8 += 2; - } - } - dst = (u32 __iomem *)dst8; - } *ppos += c; buf += c; -- 2.34.1