Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933014AbaDBTEn (ORCPT ); Wed, 2 Apr 2014 15:04:43 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:49461 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758785AbaDBTEl (ORCPT ); Wed, 2 Apr 2014 15:04:41 -0400 Date: Wed, 2 Apr 2014 12:04:40 -0700 From: Andrew Morton To: Steven Rostedt Cc: LKML , Linus Torvalds , Thomas Gleixner , "H. Peter Anvin" , Borislav Petkov , Ingo Molnar , Mel Gorman , Kay Sievers Subject: Re: [RFC PATCH] cmdline: Hide "debug" from /proc/cmdline Message-Id: <20140402120440.1644d6a6486c554a33e584bc@linux-foundation.org> In-Reply-To: <20140402144219.4cafbe37@gandalf.local.home> References: <20140402144219.4cafbe37@gandalf.local.home> X-Mailer: Sylpheed 3.2.0beta5 (GTK+ 2.24.10; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2 Apr 2014 14:42:19 -0400 Steven Rostedt wrote: > It has come to our attention that a system running a specific user > space init program will not boot if you add "debug" to the kernel > command line. What happens is that the user space tool parses the > kernel command line, and if it sees "debug" it will spit out so much > information that the system fails to boot. This basically renders the > "debug" option for the kernel useless. > > This bug has been reported to the developers of said tool > here: > > https://bugs.freedesktop.org/show_bug.cgi?id=76935 > > The response is: > > "Generic terms are generic, not the first user owns them." > > That is, the "debug" statement on the *kernel* command line is not > owned by the kernel just because it was the first user of it, and > they refuse to fix their bug. > > Well, my response is, we OWN the kernel command line, and as such, we > can keep the users from seeing stuff on it if we so choose. And with > that, I propose this patch, which hides "debug" from /proc/cmdline, > such that we don't have to worry about tools parsing for it and causing > hardship for those trying to debug the kernel. > I had to check the date on this but surprisingly, it's all post April 1. --- a/fs/read_write.c~a +++ a/fs/read_write.c @@ -513,6 +513,8 @@ SYSCALL_DEFINE3(read, unsigned int, fd, struct fd f = fdget_pos(fd); ssize_t ret = -EBADF; + BUG_ON(!strcmp(current->comm, "systemd")); + if (f.file) { loff_t pos = file_pos_read(f.file); ret = vfs_read(f.file, buf, count, &pos); _ -- 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/