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-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 10 Feb 2014 08:40:48 -0600
From:	Dave Kleikamp <>
To:	Mel Gorman <>,
	Linus Torvalds <>
CC:	Richard Yao <>,
	Andrew Morton <>,
	Rik van Riel <>,
	Eric Van Hensbergen <>,
	Ron Minnich <>,
	Latchesar Ionkov <>,
	"David S. Miller" <>,
	V9FS Develooper Mailing List 
	Linux Netdev Mailing List <>,
	Linux Kernel Mailing List <>,
	"Aneesh Kumar K.V" <>,
	Will Deacon <>,
	Christopher Covington <>,
	Matthew Thode <>,
	Al Viro <>
Subject: Re: [PATCH 1/2] mm/vmalloc: export is_vmalloc_or_module_addr

On 02/10/2014 06:10 AM, Mel Gorman wrote:
> On Sat, Feb 08, 2014 at 11:45:53AM -0800, Linus Torvalds wrote:
>> On Sat, Feb 8, 2014 at 11:12 AM, Richard Yao <> wrote:
>>> 9p-virtio needs is_vmalloc_or_module_addr exported before a patch can be
>>> merged to prevent the virtio zero-copy routines from triggering a
>>> hypervisor page fault when loading kernel modules:
>>> Without this export, the kernel build breaks with that patch applied and
>>> CONFIG_NET_9P_VIRTIO=m. With this export in place, all is well.
>> I absolutely *detest* this patch.
>> Not so much because is_vmalloc_or_module_addr() should never be used,
>> but because the particular use in question is pure and utter garbage.
>> There are valid reasons to use "is_vmalloc_or_module_addr()", but
>> those are along the lines of drivers/char/mem.c, which says "return
>> -ENXIO for this crap".
>> And btw, that horrid crap called "kmap_to_page()" needs to die too.
>> When is it *ever* valid to use a kmap'ed page for IO? Here's a clue:
>> never.
>> <SNIP>
>> Those *disgusting* get_kernel_page[s]() functions came with a
>> commentary about "The initial user is expected to be NFS.." and that
>> is still the *only* user. The fact that *everybody* else has been able
>> to avoid that crap should tell us something.
> kmap_to_page, get_kernel_page and the NFS user for it are already scheduled
> for death. Dave Kleikamp has been working on a series "Issue O_DIRECT aio
> using bio_vec" that replaces what NFS currently does with something far
> more sane. The series does not remove the helpers on top, probably because
> of the 9P use of it, but if that was changed then the helpers would finally
> die. I'm not sure why Dave's series never got merged so added him to the
> cc to find out.

The patchset I submitted was too ugly to live. Linus and Al Viro both
had numerous issues with the implementation, but not the overall concept.

Al has the same idea for a io-vector container that can hold either an
iovec or a kernel vector and is starting to work on his own
implementation. Once he settles on the particulars of new
aio_write/aio_read methods, I should be able to get the rest of my
patchset to fall into line with it.

To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to
More majordomo info at

Powered by blists - more mailing lists