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Ilya Dryomov 7e241f647d libceph: fall back to sendmsg for slab pages
skb_can_coalesce() allows coalescing neighboring slab objects into
a single frag:

  return page == skb_frag_page(frag) &&
         off == frag->page_offset + skb_frag_size(frag);

ceph_tcp_sendpage() can be handed slab pages.  One example of this is
XFS: it passes down sector sized slab objects for its metadata I/O.  If
the kernel client is co-located on the OSD node, the skb may go through
loopback and pop on the receive side with the exact same set of frags.
When tcp_recvmsg() attempts to copy out such a frag, hardened usercopy
complains because the size exceeds the object's allocated size:

  usercopy: kernel memory exposure attempt detected from ffff9ba917f20a00 (kmalloc-512) (1024 bytes)

Although skb_can_coalesce() could be taught to return false if the
resulting frag would cross a slab object boundary, we already have
a fallback for non-refcounted pages.  Utilize it for slab pages too.

Cc: stable@vger.kernel.org # 4.8+
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
2018-11-19 17:59:47 +01:00
arch Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-11-18 10:54:59 -08:00
block SCSI: fix queue cleanup race before queue initialization is done 2018-11-14 08:19:10 -07:00
certs
crypto crypto: user - Zeroize whole structure given to user space 2018-11-09 17:35:43 +08:00
Documentation Power management updates for 4.20-rc3 2018-11-14 15:33:45 -06:00
drivers libnvdimm 4.20-rc3 2018-11-18 12:21:09 -08:00
firmware
fs ocfs2: free up write context when direct IO failed 2018-11-18 10:15:09 -08:00
include Merge branch 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2018-11-18 10:52:26 -08:00
init memblock: stop using implicit alignment to SMP_CACHE_BYTES 2018-10-31 08:54:16 -07:00
ipc ipc: IPCMNI limit check for semmni 2018-10-31 08:54:14 -07:00
kernel Merge branch 'akpm' (patches from Andrew) 2018-11-18 11:31:26 -08:00
lib lib/ubsan.c: don't mark __ubsan_handle_builtin_unreachable as noreturn 2018-11-18 10:15:10 -08:00
LICENSES This is a fairly typical cycle for documentation. There's some welcome 2018-10-24 18:01:11 +01:00
mm mm/memblock.c: fix a typo in __next_mem_pfn_range() comments 2018-11-18 10:15:10 -08:00
net libceph: fall back to sendmsg for slab pages 2018-11-19 17:59:47 +01:00
samples VFIO updates for v4.20 2018-10-31 11:01:38 -07:00
scripts scripts/spdxcheck.py: make python3 compliant 2018-11-18 10:15:10 -08:00
security selinux/stable-4.20 PR 20181115 2018-11-15 11:26:09 -06:00
sound ALSA: hda - Fix incorrect clearance of thinkpad_acpi hooks 2018-11-06 16:33:53 +01:00
tools libnvdimm 4.20-rc3 2018-11-18 12:21:09 -08:00
usr
virt Revert "mm, mmu_notifier: annotate mmu notifiers with blockable invalidate callbacks" 2018-10-26 16:25:19 -07:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap mailmap: Update email for Punit Agrawal 2018-11-05 10:02:11 +00:00
COPYING
CREDITS MAINTAINERS: update OMAP MMC entry 2018-11-18 10:15:09 -08:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig
MAINTAINERS MAINTAINERS: update OMAP MMC entry 2018-11-18 10:15:09 -08:00
Makefile Linux 4.20-rc3 2018-11-18 13:33:44 -08:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.