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Anssi Hannula 98876c46ef net: macb: add missing barriers when reading descriptors
[ Upstream commit 6e0af29806 ]

When reading buffer descriptors on RX or on TX completion, an
RX_USED/TX_USED bit is checked first to ensure that the descriptors have
been populated, i.e. the ownership has been transferred. However, there
are no memory barriers to ensure that the data protected by the
RX_USED/TX_USED bit is up-to-date with respect to that bit.

Specifically:

- TX timestamp descriptors may be loaded before ctrl is loaded for the
  TX_USED check, which is racy as the descriptors may be updated between
  the loads, causing old timestamp descriptor data to be used.

- RX ctrl may be loaded before addr is loaded for the RX_USED check,
  which is racy as a new frame may be written between the loads, causing
  old ctrl descriptor data to be used.
  This issue exists for both macb_rx() and gem_rx() variants.

Fix the races by adding DMA read memory barriers on those paths and
reordering the reads in macb_rx().

I have not observed any actual problems in practice caused by these
being missing, though.

Tested on a ZynqMP based system.

Fixes: 89e5785fc8 ("[PATCH] Atmel MACB ethernet driver")
Signed-off-by: Anssi Hannula <anssi.hannula@bitwise.fi>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-01-13 09:51:02 +01:00
arch x86/dump_pagetables: Fix LDT remap address marker 2019-01-13 09:50:58 +01:00
block block/bio: Do not zero user pages 2018-12-19 19:19:50 +01:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: cfb - fix decryption 2019-01-09 17:38:45 +01:00
Documentation x86/speculation/l1tf: Drop the swap storage limit restriction when l1tf=off 2019-01-09 17:38:41 +01:00
drivers net: macb: add missing barriers when reading descriptors 2019-01-13 09:51:02 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs smb3: fix large reads on encrypted connections 2019-01-09 17:38:48 +01:00
include netfilter: nf_tables: fix suspicious RCU usage in nft_chain_stats_replace() 2019-01-13 09:50:57 +01:00
init sched/pelt: Fix warning and clean up IRQ PELT config 2018-12-19 19:19:49 +01:00
ipc ipc/shm.c: use ERR_CAST() for shm_lock() error return 2018-10-05 16:32:04 -07:00
kernel cgroup: fix CSS_TASK_ITER_PROCS 2019-01-09 17:38:45 +01:00
lib debugobjects: avoid recursive calls with kmemleak 2018-12-17 09:24:41 +01:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm: don't miss the last page because of round-off error 2018-12-29 13:37:59 +01:00
net SUNRPC: Fix a race with XPRT_CONNECTING 2019-01-13 09:51:01 +01:00
samples samples: disable CONFIG_SAMPLES for UML 2018-10-11 02:15:46 +09:00
scripts checkstack.pl: fix for aarch64 2019-01-13 09:50:57 +01:00
security selinux: add support for RTM_NEWCHAIN, RTM_DELCHAIN, and RTM_GETCHAIN 2018-12-08 12:59:08 +01:00
sound ASoC: intel: cht_bsw_max98090_ti: Add pmc_plt_clk_0 quirk for Chromebook Gnawty 2019-01-09 17:38:41 +01:00
tools tools lib traceevent: Fix processing of dereferenced args in bprintk events 2019-01-09 17:38:47 +01:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: arm/arm64: vgic: Fix off-by-one bug in vgic_get_irq() 2019-01-09 17:38:49 +01:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore Kbuild updates for v4.17 (2nd) 2018-04-15 17:21:30 -07:00
.mailmap libnvdimm-for-4.19_misc 2018-08-25 18:13:10 -07:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS 9p: remove Ron Minnich from MAINTAINERS 2018-08-17 16:20:26 -07:00
Kbuild Kbuild updates for v4.15 2017-11-17 17:45:29 -08:00
Kconfig kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
MAINTAINERS MAINTAINERS: Add Sasha as a stable branch maintainer 2018-12-01 09:37:25 +01:00
Makefile Linux 4.19.14 2019-01-09 17:38:50 +01:00
README Docs: Added a pointer to the formatted docs to README 2018-03-21 09:02:53 -06:00

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.
See Documentation/00-INDEX for a list of what is contained in each file.

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.