Hi!

W dniu 2016-08-05 21:47, Eric Wheeler napisał(a):

On Fri, 5 Aug 2016, Marcin Mirosław wrote:

quoted

Hi!
Kernel is on commit 1c99b8fdce303e0961ee982919c890bf156ed775.
Host is freshly rebooted.
# grep bcache /proc/modules
# modprobe bcache && rmmod bcache && modprobe bcache
modprobe: ERROR: could not insert 'bcache': Cannot allocate memory

In dmesg I've got:

quoted

Aug  5 15:39:14 localhost kernel: [  249.911487] WARNING: CPU: 3 PID: 17892 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x5d/0x70
Aug  5 15:39:14 localhost kernel: [  249.911490] sysfs: cannot create duplicate filename '/devices/virtual/bcache'

Hmm, it looks like something in sysfs might not get unregistered at 
module
unload time, so reloading it causes the warning.

Are you using bcache or bcachefs?  I don't see bch_fs_init() in 4.7:

http://lxr.free-electrons.com/ident?i=bch_fs_init
	< empty >

If bcachefs, please update the subject when you reply.

$ grep -R  bch_fs_init drivers/md/bcache/*.{c,h}
drivers/md/bcache/fs.c:int __init bch_fs_init(void)
drivers/md/bcache/super.c:          bch_fs_init() ||
drivers/md/bcache/bcache.h:int bch_fs_init(void);

I'm little confused. Module name is "bcache" and I used it in subject 
because I couldn't load such module. I think that this module supports 
both bcache (cache device) and bcachefs. And yes, I'm using kernel tree 
with bcachefs support:)

Marcin