linux-kernel - generic_setlease and tmpfs -- LTP fcntl failure

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: Windows password security audit tool. GUI, reports in PDF.

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

Date:	Wed, 14 Nov 2007 15:19:31 -0600
From:	Kumar Gala <galak@...nel.crashing.org>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: generic_setlease and tmpfs -- LTP fcntl failure

In debugging a LTP failure related to fcntl on tmpfs it appears that  
we aren't able to use fcntl(fd, F_SETLEASE, F_WRLCK).  In the  
debugging it looks like we artificial increase the dentry->d_count  
and so generic_setlease() always fails with -EAGAIN since it appears  
dentry->d_count will be 2.

This is my first time delving into fs code so I'm not that familiar  
with why tmpfs is artificially increasing the d_count.  I was  
wondering what a possible solution would be.

Maybe something like:

shmem_setlease(...) {
	if (arg == F_WRLCK) {
		dput(dentry)
		generic_setlease(...)
		dget(dentry)
	} else {
		generic_setlease(...)
	}
}

Not sure what harm doing the dput() / dget() will have.

- k
-
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/