Re: [BUG] 3.7-rc regression bisected: s2disk fails to resume image: Processes could not be frozen, cannot continue resuming

[Al Viro <viro@ZenIV.linux.org.uk>]

On Tue, Aug 27, 2013 at 07:48:43AM +0400, Andrew Savchenko wrote:
> > Additional (but probably useless) information on this bug may be found
> > here: https://forums.gentoo.org/viewtopic-p-7371120.html

Something's very fishy there:

[quote]
Digging into suspend-utils code shows that the following ioctl fails on      
"/dev/snapshot":                                                             
                                                                                
                                    Code:                                       
                          ioctl(dev, _IO(3, 1), 0);                          
[end quote]

but that's _not_ anything freeze-related - that's HDIO_GETGEO, and with zero
as last argument it will fail, no matter what.  With EFAULT, if nothing
else...

Which ioctl() it really is?  A bit further down you write "I modified suspend
code to see errno, so freeze on /dev/snapshot fails [with EAGAIN]", so you
have isolated the call in question.  Could you quote the actual code?