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Mainline Linux tree for various devices, only for fun :)
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Krister Johansen f186ce61bb Fix an intermittent pr_emerg warning about lo becoming free.
It looks like this:

Message from syslogd@flamingo at Apr 26 00:45:00 ...
 kernel:unregister_netdevice: waiting for lo to become free. Usage count = 4

They seem to coincide with net namespace teardown.

The message is emitted by netdev_wait_allrefs().

Forced a kdump in netdev_run_todo, but found that the refcount on the lo
device was already 0 at the time we got to the panic.

Used bcc to check the blocking in netdev_run_todo.  The only places
where we're off cpu there are in the rcu_barrier() and msleep() calls.
That behavior is expected.  The msleep time coincides with the amount of
time we spend waiting for the refcount to reach zero; the rcu_barrier()
wait times are not excessive.

After looking through the list of callbacks that the netdevice notifiers
invoke in this path, it appears that the dst_dev_event is the most
interesting.  The dst_ifdown path places a hold on the loopback_dev as
part of releasing the dev associated with the original dst cache entry.
Most of our notifier callbacks are straight-forward, but this one a)
looks complex, and b) places a hold on the network interface in
question.

I constructed a new bcc script that watches various events in the
liftime of a dst cache entry.  Note that dst_ifdown will take a hold on
the loopback device until the invalidated dst entry gets freed.

[      __dst_free] on DST: ffff883ccabb7900 IF tap1008300eth0 invoked at 1282115677036183
    __dst_free
    rcu_nocb_kthread
    kthread
    ret_from_fork
Acked-by: Eric Dumazet <edumazet@google.com>

Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-09 12:27:28 -04:00
arch bpf, arm64: use separate register for state in stxr 2017-06-07 15:27:20 -04:00
block block: Avoid that blk_exit_rl() triggers a use-after-free 2017-06-01 13:07:55 -06:00
certs scripts/spelling.txt: add "intialise(d)" pattern and fix typo instances 2017-05-08 17:15:13 -07:00
crypto crypto: skcipher - Add missing API setkey checks 2017-05-18 13:04:05 +08:00
Documentation net: fix up hash documentation 2017-06-07 13:00:41 -04:00
drivers net: phy: add missing SPEED_14000 2017-06-09 09:53:25 -04:00
firmware firmware/Makefile: force recompilation if makefile changes 2017-05-08 17:15:10 -07:00
fs fs/ufs: Set UFS default maximum bytes per file 2017-06-04 16:33:54 -07:00
include ethtool.h: remind to update 802.3ad when adding new speeds 2017-06-08 16:05:41 -04:00
init Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-05-10 10:30:46 -07:00
ipc mm: introduce kv[mz]alloc helpers 2017-05-08 17:15:12 -07:00
kernel Merge branch 'for-4.12-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 2017-06-05 15:37:03 -07:00
lib test_bpf: Add a couple of tests for BPF_JSGE. 2017-05-25 14:37:56 -04:00
mm mm: consider memblock reservations for deferred memory initialization sizing 2017-06-02 15:07:38 -07:00
net Fix an intermittent pr_emerg warning about lo becoming free. 2017-06-09 12:27:28 -04:00
samples samples/bpf: run cleanup routines when receiving SIGTERM 2017-05-11 21:43:30 -04:00
scripts scripts/gdb: make lx-dmesg command work (reliably) 2017-06-02 15:07:38 -07:00
security Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2017-05-09 09:12:53 -07:00
sound sound fixes for 4.12-rc4 2017-06-02 09:40:47 -07:00
tools bpf, tests: fix endianness selection 2017-06-08 16:17:29 -04:00
usr initramfs: fix disabling of initramfs (and its compression) 2017-06-02 15:07:37 -07:00
virt KVM: arm/arm64: Hold slots_lock when unregistering kvm io bus devices 2017-05-18 11:18:16 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore kbuild: Add support to generate LLVM assembly files 2017-04-25 08:13:52 +09:00
.mailmap power supply and reset changes for the v4.12 series (part 2) 2017-05-12 12:02:21 -07:00
COPYING
CREDITS avr32: remove support for AVR32 architecture 2017-05-01 09:27:15 +02:00
Kbuild kbuild: Consolidate header generation from ASM offset information 2017-04-13 05:43:37 +09:00
Kconfig
MAINTAINERS Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-06-06 14:30:17 -07:00
Makefile Linux 4.12-rc4 2017-06-04 16:47:43 -07:00
README README: add a new README file, pointing to the Documentation/ 2016-10-24 08:12:35 -02:00

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.