No description
  • C 98.2%
  • Assembly 1%
  • Makefile 0.3%
  • Shell 0.2%
  • Python 0.1%
Find a file
Repository files (latest commit first)
Filename Latest commit message Latest commit date
Vladimir Oltean fcc0000109 gianfar: Fix TX timestamping with a stacked DSA driver
[ Upstream commit c26a2c2ddc0115eb088873f5c309cf46b982f522 ]

The driver wrongly assumes that it is the only entity that can set the
SKBTX_IN_PROGRESS bit of the current skb. Therefore, in the
gfar_clean_tx_ring function, where the TX timestamp is collected if
necessary, the aforementioned bit is used to discriminate whether or not
the TX timestamp should be delivered to the socket's error queue.

But a stacked driver such as a DSA switch can also set the
SKBTX_IN_PROGRESS bit, which is actually exactly what it should do in
order to denote that the hardware timestamping process is undergoing.

Therefore, gianfar would misinterpret the "in progress" bit as being its
own, and deliver a second skb clone in the socket's error queue,
completely throwing off a PTP process which is not expecting to receive
it, _even though_ TX timestamping is not enabled for gianfar.

There have been discussions [0] as to whether non-MAC drivers need or
not to set SKBTX_IN_PROGRESS at all (whose purpose is to avoid sending 2
timestamps, a sw and a hw one, to applications which only expect one).
But as of this patch, there are at least 2 PTP drivers that would break
in conjunction with gianfar: the sja1105 DSA switch and the felix
switch, by way of its ocelot core driver.

So regardless of that conclusion, fix the gianfar driver to not do stuff
based on flags set by others and not intended for it.

[0]: https://www.spinics.net/lists/netdev/msg619699.html

Fixes: f0ee7acfcd ("gianfar: Add hardware TX timestamping support")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-02-24 08:36:24 +01:00
arch KVM: x86/mmu: Fix struct guest_walker arrays for 5-level paging 2020-02-19 19:53:09 +01:00
block
certs
crypto crypto: testmgr - don't try to decrypt uninitialized buffers 2020-02-14 16:34:18 -05:00
Documentation dt-bindings: iio: adc: ad7606: Fix wrong maxItems value 2020-02-14 16:34:19 -05:00
drivers gianfar: Fix TX timestamping with a stacked DSA driver 2020-02-24 08:36:24 +01:00
fs ext4: fix ext4_dax_read/write inode locking sequence for IOCB_NOWAIT 2020-02-24 08:36:24 +01:00
include rcu: Fix data-race due to atomic_t copy-by-value 2020-02-24 08:36:23 +01:00
init
ipc
kernel cpu/hotplug, stop_machine: Fix stop_machine vs hotplug order 2020-02-24 08:36:23 +01:00
lib
LICENSES
mm mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flush 2020-02-11 04:35:42 -08:00
net net/sched: flower: add missing validation of TCA_FLOWER_FLAGS 2020-02-24 08:36:22 +01:00
samples samples/bpf: Xdp_redirect_cpu fix missing tracepoint attach 2020-02-11 04:35:29 -08:00
scripts
security selinux: fall back to ref-walk if audit is required 2020-02-14 16:34:20 -05:00
sound ALSA: ctl: allow TLV read operation for callback type of element in locked case 2020-02-24 08:36:24 +01:00
tools perf stat: Don't report a null stalled cycles per insn metric 2020-02-19 19:53:08 +01:00
usr
virt KVM: arm64: Treat emulated TVAL TimerValue as a signed 32-bit integer 2020-02-14 16:34:18 -05:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile Linux 5.4.21 2020-02-19 19:53:10 +01:00
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.