linux/fs/fuse
Linus Torvalds 6b3a707736 Merge branch 'page-refs' (page ref overflow)
Merge page ref overflow branch.

Jann Horn reported that he can overflow the page ref count with
sufficient memory (and a filesystem that is intentionally extremely
slow).

Admittedly it's not exactly easy.  To have more than four billion
references to a page requires a minimum of 32GB of kernel memory just
for the pointers to the pages, much less any metadata to keep track of
those pointers.  Jann needed a total of 140GB of memory and a specially
crafted filesystem that leaves all reads pending (in order to not ever
free the page references and just keep adding more).

Still, we have a fairly straightforward way to limit the two obvious
user-controllable sources of page references: direct-IO like page
references gotten through get_user_pages(), and the splice pipe page
duplication.  So let's just do that.

* branch page-refs:
  fs: prevent page refcount overflow in pipe_buf_get
  mm: prevent get_user_pages() from overflowing page refcount
  mm: add 'try_get_page()' helper function
  mm: make page ref count overflow check tighter and more explicit
2019-04-14 15:09:40 -07:00
..
Kconfig fuse: Add posix ACL support 2016-10-01 07:32:32 +02:00
Makefile fuse: split out readdir.c 2018-09-28 16:43:23 +02:00
acl.c fuse: Support fuse filesystems outside of init_user_ns 2018-03-20 17:11:44 +01:00
control.c fuse: clean up aborted 2019-02-13 13:15:14 +01:00
cuse.c fuse: clean up aborted 2019-02-13 13:15:14 +01:00
dev.c Merge branch 'page-refs' (page ref overflow) 2019-04-14 15:09:40 -07:00
dir.c fuse: Protect fi->nlookup with fi->lock 2019-02-13 13:15:14 +01:00
file.c fuse: cache readdir calls if filesystem opts out of opendir 2019-02-13 13:15:15 +01:00
fuse_i.h fuse: support clients that don't implement 'opendir' 2019-02-13 13:15:15 +01:00
inode.c fuse update for 5.1 2019-03-12 14:46:26 -07:00
readdir.c fuse: Protect fi->nlookup with fi->lock 2019-02-13 13:15:14 +01:00
xattr.c fuse: Ensure posix acls are translated outside of init_user_ns 2018-05-31 12:26:10 +02:00