Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758615Ab0FQAlK (ORCPT ); Wed, 16 Jun 2010 20:41:10 -0400 Received: from [159.226.40.154] ([159.226.40.154]:39547 "EHLO mail.loongson.cn" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753578Ab0FQAlG (ORCPT ); Wed, 16 Jun 2010 20:41:06 -0400 From: qiaochong To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, jsimmons@infradead.org, qiaochong@loongson.cn Subject: [PATCH 1/2] fix vc->vc_origin on take_over_console. Date: Thu, 17 Jun 2010 08:41:24 +0800 Message-Id: <1276735285-7045-2-git-send-email-qiaochong@loongson.cn> X-Mailer: git-send-email 1.7.0.3.254.g4503b.dirty In-Reply-To: <1276735285-7045-1-git-send-email-qiaochong@loongson.cn> References: <1276735285-7045-1-git-send-email-qiaochong@loongson.cn> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2283 Lines: 66 kernel will die on some platform when switch from vga mode to framebuffer mode. The reason of this bug is that bind_con_driver reset vc->vc_origin to (unsigned long)vc->vc_screenbuf. On vgacon vc->vc_origin is not releated to vc->vc_screenbuf,if set vc->vc_origin to vc->vc_screenbuf,kernel will die on vc_do_resize. static int vc_do_resize(struct tty_struct *tty, struct tty_struct *real_tty, struct vc_data *vc, unsigned int cols, unsigned int lines) { unsigned long old_origin, new_origin, new_scr_end, rlth, rrem, err = 0; unsigned int old_cols, old_rows, old_row_size, old_screen_size; unsigned int new_cols, new_rows, new_row_size, new_screen_size; unsigned int end, user; ... end = (old_rows > new_rows) ? old_origin + (old_row_size * new_rows) : vc->vc_scr_end; ... /* here for a test from vgacon to framebuffer: old_origin=0x810814a0,end=0xb00b8fa0,vc->vc_origin=0x810814a0 the code bellow will copy memory from 0x810814a0 to 0xb00b8fa0, this will cover kernel code,kernel died here. */ while (old_origin < end) { scr_memcpyw((unsigned short *) new_origin, (unsigned short *) old_origin, rlth); if (rrem) scr_memsetw((void *)(new_origin + rlth), vc->vc_video_erase_char, rrem); old_origin += old_row_size; new_origin += new_row_size; } ... } Signed-off-by: qiaochong --- drivers/char/vt.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/drivers/char/vt.c b/drivers/char/vt.c index 50faa1f..29a5bdc 100644 --- a/drivers/char/vt.c +++ b/drivers/char/vt.c @@ -3063,7 +3063,8 @@ static int bind_con_driver(const struct consw *csw, int first, int last, old_was_color = vc->vc_can_do_color; vc->vc_sw->con_deinit(vc); - vc->vc_origin = (unsigned long)vc->vc_screenbuf; + if (!vc->vc_origin) + vc->vc_origin = (unsigned long)vc->vc_screenbuf; visual_init(vc, i, 0); set_origin(vc); update_attr(vc); -- 1.5.6.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/