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Filename Latest commit message Latest commit date
Jacob Keller 5012863b73 e1000e: fix race condition around skb_tstamp_tx()
The e1000e driver and related hardware has a limitation on Tx PTP
packets which requires we limit to timestamping a single packet at once.
We do this by verifying that we never request a new Tx timestamp while
we still have a tx_hwtstamp_skb pointer.

Unfortunately the driver suffers from a race condition around this. The
tx_hwtstamp_skb pointer is not set to NULL until after skb_tstamp_tx()
is called. This function notifies the stack and applications of a new
timestamp. Even a well behaved application that only sends a new request
when the first one is finished might be woken up and possibly send
a packet before we can free the timestamp in the driver again. The
result is that we needlessly ignore some Tx timestamp requests in this
corner case.

Fix this by assigning the tx_hwtstamp_skb pointer prior to calling
skb_tstamp_tx() and use a temporary pointer to hold the timestamped skb
until that function finishes. This ensures that the application is not
woken up until the driver is ready to begin timestamping a new packet.

This ensures that well behaved applications do not accidentally race
with condition to skip Tx timestamps. Obviously an application which
sends multiple Tx timestamp requests at once will still only timestamp
one packet at a time. Unfortunately there is nothing we can do about
this.

Reported-by: David Mirabito <davidm@metamako.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2017-06-06 00:52:17 -07:00
arch arm64: defconfig: Enable dwmac-sun8i driver on defconfig 2017-06-01 14:53:09 -04:00
block Merge branch 'nvme-4.12' of git://git.infradead.org/nvme into for-linus 2017-05-26 09:11:19 -06:00
certs
crypto crypto: skcipher - Add missing API setkey checks 2017-05-18 13:04:05 +08:00
Documentation i40evf: update i40evf.txt with new content 2017-06-01 14:31:37 -07:00
drivers e1000e: fix race condition around skb_tstamp_tx() 2017-06-06 00:52:17 -07:00
firmware
fs Changed since last update: 2017-05-26 12:13:08 -07:00
include net/{mii, smsc}: Make mii_ethtool_get_link_ksettings and smc_netdev_get_ecmd return void 2017-06-05 11:00:42 -04:00
init
ipc
kernel perf, bpf: Add BPF support to all perf_event types 2017-06-04 21:58:01 -04:00
lib bpf: fix stack_depth usage by test_bpf.ko 2017-05-31 19:29:48 -04:00
mm mm: vmscan: scan until it finds eligible pages 2017-05-12 15:57:16 -07:00
net net: sched: select cls when cls_act is enabled 2017-06-05 10:56:36 -04:00
samples samples/bpf: add tests for more perf event types 2017-06-04 21:58:15 -04:00
scripts DeviceTree fixes for 4.12-rc: 2017-05-19 15:03:24 -07:00
security
sound sound fixes for 4.12-rc3 2017-05-26 09:03:09 -07:00
tools bpf: update perf event helper functions documentation 2017-06-04 21:58:16 -04:00
usr
virt KVM: arm/arm64: Hold slots_lock when unregistering kvm io bus devices 2017-05-18 11:18:16 +02:00
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS i40e/i40evf: create and use new unified header file 2017-06-01 14:04:42 -07:00
Makefile Linux 4.12-rc2 2017-05-21 19:30:23 -07:00
README

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

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

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.