linux-kernel - Re: Advice on mmap() "feature"

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20120917121717.2c99d28f@pyramind.ukuu.org.uk>
Date:	Mon, 17 Sep 2012 12:17:17 +0100
From:	Alan Cox <alan@...rguk.ukuu.org.uk>
To:	Mark Jackson <mpfj-list@...c.co.uk>
Cc:	lkml <linux-kernel@...r.kernel.org>
Subject: Re: Advice on mmap() "feature"

> (a) Since all the mappings have been removed, so why don't the fd's get 
> released ?

Because your code is buggy.

Firstly its files it keeps a reference to not file handles, so your close
closes the file handle. You do however end up with lots of file structs
pinned and that's because you've got a bug.

You map twice as much as you unmap, the kernel therefore keeps the second
half mapped for you. Fix your munmap and all will be happy.

You owe the oracle an ice cream

Alan
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/