From mboxrd@z Thu Jan 1 00:00:00 1970 From: chrubis-AlSwsSmVLrQ@public.gmane.org Subject: Re: [PATCH] mmap.2: Add note about partial page in BUGS section Date: Wed, 27 Feb 2013 15:10:33 +0100 Message-ID: <20130227141033.GA1797@rei> References: <20121112112544.GC6764@rei.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-man-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: "Michael Kerrisk (man-pages)" Cc: linux-man-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-man@vger.kernel.org Hi! > I also tweaked the patch a little. The most notable change is that I > changed your reference to "shm ipc" to "POSIX shared memory". Please > let me know if that was incorrect. > > POSIX specifies that the system shall always zero fill any par??? > tial page at the end of the object and that system will never > write any modification of the object beyond its end. On Linux, > when you write data to such partial page after the end of the > object, the data stays in the page cache even after the file is > closed and unmapped and even though the data is never written > to the file itself, subsequent mappings may see the modified > content. In some cases, this could be fixed by calling > msync(2) before the unmap takes place; however, this doesn't > work on tmpfs (for example, when using POSIX shared memory > interface documented in shm_overview(7)). Thanks, that is better. And out of curiosity, where is the most current man-pages git repo? There seems to be github one and kernel.org one and they are out of sync. -- Cyril Hrubis chrubis-AlSwsSmVLrQ@public.gmane.org -- To unsubscribe from this list: send the line "unsubscribe linux-man" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html