Re: [PATCH 00/10] mm: adjust get_user_pages* functions to explicitly pass FOLL_* flags

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Wed 19-10-16 09:58:15, Lorenzo Stoakes wrote:
> On Tue, Oct 18, 2016 at 05:30:50PM +0200, Michal Hocko wrote:
> > I am wondering whether we can go further. E.g. it is not really clear to
> > me whether we need an explicit FOLL_REMOTE when we can in fact check
> > mm != current->mm and imply that. Maybe there are some contexts which
> > wouldn't work, I haven't checked.
> 
> This flag is set even when /proc/self/mem is used. I've not looked deeply into
> this flag but perhaps accessing your own memory this way can be considered
> 'remote' since you're not accessing it directly. On the other hand, perhaps this
> is just mistaken in this case?

My understanding of the flag is quite limited as well. All I know it is
related to protection keys and it is needed to bypass protection check.
See arch_vma_access_permitted. See also 1b2ee1266ea6 ("mm/core: Do not
enforce PKEY permissions on remote mm access").

-- 
Michal Hocko
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux