From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 27 Aug 2001 16:05:32 +0100 From: "Stephen C. Tweedie" Subject: Re: can i call copy_to_user with interrupts masked Message-ID: <20010827160532.H5970@redhat.com> References: <20010827145640.79597.qmail@web14201.mail.yahoo.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20010827145640.79597.qmail@web14201.mail.yahoo.com>; from pras_chakra@yahoo.com on Mon, Aug 27, 2001 at 07:56:40AM -0700 Sender: owner-linux-mm@kvack.org Return-Path: To: PRASENJIT CHAKRABORTY Cc: linux-mm@kvack.org, arund@bellatlantic.net List-ID: Hi, On Mon, Aug 27, 2001 at 07:56:40AM -0700, PRASENJIT CHAKRABORTY wrote: > This is in continuation with my previous mail. > While debugging I've noticed that __copy_to_user() > fails when I stop the Bottom Half before the call to > __copy_to_user(), so if the page in not currently > mapped then it forbids do_page_fault() to get invoked > and hence the failure. You're doing copy_to_user from a bottom half?????? You cannot do that. *Ever*. It's illegal to take page faults from an interrupt of any sort. Cheers, STephen -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/