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Florian Fainelli 3d6679c85a net: systemport: Protect stop from timeout
[ Upstream commit 7cb6a2a2c7 ]

A timing hazard exists when the network interface is stopped that
allows a watchdog timeout to be processed by a separate core in
parallel. This creates the potential for the timeout handler to
wake the queues while the driver is shutting down, or access
registers after their clocks have been removed.

The more common case is that the watchdog timeout will produce a
warning message which doesn't lead to a crash. The chances of this
are greatly increased by the fact that bcm_sysport_netif_stop stops
the transmit queues which can easily precipitate a watchdog time-
out because of stale trans_start data in the queues.

This commit corrects the behavior by ensuring that the watchdog
timeout is disabled before enterring bcm_sysport_netif_stop. There
are currently only two users of the bcm_sysport_netif_stop function:
close and suspend.

The close case already handles the issue by exiting the RUNNING
state before invoking the driver close service.

The suspend case now performs the netif_device_detach to exit the
PRESENT state before the call to bcm_sysport_netif_stop rather than
after it.

These behaviors prevent any future scheduling of the driver timeout
service during the window. The netif_tx_stop_all_queues function
in bcm_sysport_netif_stop is replaced with netif_tx_disable to ensure
synchronization with any transmit or timeout threads that may
already be executing on other cores.

For symmetry, the netif_device_attach call upon resume is moved to
after the call to bcm_sysport_netif_start. Since it wakes the transmit
queues it is not necessary to invoke netif_tx_start_all_queues from
bcm_sysport_netif_start so it is moved into the driver open service.

Fixes: 40755a0fce ("net: systemport: add suspend and resume support")
Fixes: 80105befdb ("net: systemport: add Broadcom SYSTEMPORT Ethernet MAC driver")
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
History 2018-11-23 08:17:03 +01:00
arch arch/alpha, termios: implement BOTHER, IBSHIFT and termios2 2018-11-21 09:19:20 +01:00
block SCSI: fix queue cleanup race before queue initialization is done 2018-11-21 09:19:18 +01:00
certs export.h: remove VMLINUX_SYMBOL() and VMLINUX_SYMBOL_STR() 2018-08-22 23:21:44 +09:00
crypto crypto: user - fix leaking uninitialized memory to userspace 2018-11-21 09:19:24 +01:00
Documentation ovl: automatically enable redirect_dir on metacopy=on 2018-11-21 09:19:13 +01:00
drivers net: systemport: Protect stop from timeout 2018-11-23 08:17:03 +01:00
firmware kbuild: remove all dummy assignments to obj- 2017-11-18 11:46:06 +09:00
fs mm: don't reclaim inodes with many attached pages 2018-11-21 09:19:25 +01:00
include CONFIG_XEN_PV breaks xen_create_contiguous_region on ARM 2018-11-21 09:19:28 +01:00
init Kbuild updates for v4.19 (2nd) 2018-08-25 13:40:38 -07:00
ipc ipc/shm.c: use ERR_CAST() for shm_lock() error return 2018-10-05 16:32:04 -07:00
kernel kdb: print real address of pointers instead of hashed addresses 2018-11-21 09:19:23 +01:00
lib lib/ubsan.c: don't mark __ubsan_handle_builtin_unreachable as noreturn 2018-11-21 09:19:24 +01:00
LICENSES LICENSES: Remove CC-BY-SA-4.0 license text 2018-10-18 11:28:50 +02:00
mm mm/swapfile.c: use kvzalloc for swap_info_struct allocation 2018-11-21 09:19:24 +01:00
net tipc: fix lockdep warning when reinitilaizing sockets 2018-11-23 08:17:03 +01:00
samples samples: disable CONFIG_SAMPLES for UML 2018-10-11 02:15:46 +09:00
scripts scripts/spdxcheck.py: make python3 compliant 2018-11-21 09:19:25 +01:00
security selinux: check length properly in SCTP bind hook 2018-11-21 09:19:24 +01:00
sound ASoC: sta32x: set ->component pointer in private struct 2018-11-13 11:08:42 -08:00
tools perf intel-pt: Insert callchain context into synthesized callchains 2018-11-21 09:19:19 +01:00
usr initramfs: move gen_initramfs_list.sh from scripts/ to usr/ 2018-08-22 23:21:44 +09:00
virt KVM: arm64: Fix caching of host MDCR_EL2 value 2018-11-13 11:08:47 -08:00
.clang-format clang-format: Set IndentWrappedFunctionNames false 2018-08-01 18:38:51 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Add hch to .get_maintainer.ignore 2015-08-21 14:30:10 -07:00
.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 an entry for the code of conduct 2018-10-22 07:33:36 +01:00
Makefile Linux 4.19.3 2018-11-21 09:19:29 +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.