From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ard Biesheuvel Subject: [PATCH 11/11] efi/x86: earlyprintk - Fix infinite loop on some screen widths Date: Thu, 29 Nov 2018 18:12:30 +0100 Message-ID: <20181129171230.18699-12-ard.biesheuvel@linaro.org> References: <20181129171230.18699-1-ard.biesheuvel@linaro.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20181129171230.18699-1-ard.biesheuvel@linaro.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-efi@vger.kernel.org, Ingo Molnar , Thomas Gleixner Cc: Ard Biesheuvel , linux-kernel@vger.kernel.org, Andy Lutomirski , Arend van Spriel , Bhupesh Sharma , Borislav Petkov , Dave Hansen , Eric Snowberg , Hans de Goede , Joe Perches , Jon Hunter , Julien Thierry , Marc Zyngier , Nathan Chancellor , Peter Zijlstra , Sai Praneeth Prakhya , Sedat Dilek , YiFei Zhu List-Id: linux-efi@vger.kernel.org From: YiFei Zhu An affected screen resolution is 1366 x 768, which width is not divisible by 8, the default font width. On such screens, when longer lines are earlyprintk'ed, overflow-to-next-line can never trigger, due to the left-most x-coordinate of the next character always less than the screen width. Earlyprintk will infinite loop in trying to print the rest of the string but unable to, due to the line being full. This patch makes the trigger consider the right-most x-coordinate, instead of left-most, as the value to compare against the screen width threshold. Signed-off-by: YiFei Zhu Signed-off-by: Ard Biesheuvel --- arch/x86/platform/efi/early_printk.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/platform/efi/early_printk.c b/arch/x86/platform/efi/early_printk.c index 7476b3b097e1..7138bc7a265c 100644 --- a/arch/x86/platform/efi/early_printk.c +++ b/arch/x86/platform/efi/early_printk.c @@ -183,7 +183,7 @@ early_efi_write(struct console *con, const char *str, unsigned int num) num--; } - if (efi_x >= si->lfb_width) { + if (efi_x + font->width > si->lfb_width) { efi_x = 0; efi_y += font->height; } -- 2.19.1