Josh Poimboeuf 3ec24776bf livepatch: allow removal of a disabled patch ... Currently we do not allow patch module to unload since there is no method to determine if a task is still running in the patched code. The consistency model gives us the way because when the unpatching finishes we know that all tasks were marked as safe to call an original function. Thus every new call to the function calls the original code and at the same time no task can be somewhere in the patched code, because it had to leave that code to be marked as safe. We can safely let the patch module go after that. Completion is used for synchronization between module removal and sysfs infrastructure in a similar way to commit 942e443127 ("module: Fix mod->mkobj.kobj potentially freed too early"). Note that we still do not allow the removal for immediate model, that is no consistency model. The module refcount may increase in this case if somebody disables and enables the patch several times. This should not cause any harm. With this change a call to try_module_get() is moved to __klp_enable_patch from klp_register_patch to make module reference counting symmetric (module_put() is in a patch disable path) and to allow to take a new reference to a disabled module when being enabled. Finally, we need to be very careful about possible races between klp_unregister_patch(), kobject_put() functions and operations on the related sysfs files. kobject_put(&patch->kobj) must be called without klp_mutex. Otherwise, it might be blocked by enabled_store() that needs the mutex as well. In addition, enabled_store() must check if the patch was not unregisted in the meantime. There is no need to do the same for other kobject_put() callsites at the moment. Their sysfs operations neither take the lock nor they access any data that might be freed in the meantime. There was an attempt to use kobjects the right way and prevent these races by design. But it made the patch definition more complicated and opened another can of worms. See https://lkml.kernel.org/r/1464018848-4303-1-git-send-email-pmladek@suse.com [Thanks to Petr Mladek for improving the commit message.] Signed-off-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Acked-by: Miroslav Benes <mbenes@suse.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>		2017-03-08 09:38:43 +01:00
..
ABI	livepatch: change to a per-task consistency model	2017-03-08 09:36:21 +01:00
accounting
acpi	scripts/spelling.txt: add "followings" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
admin-guide	scripts/spelling.txt: add "an user" pattern and fix typo instances	2017-02-27 18:43:46 -08:00
aoe
arm	arm: sunxi: add support for V3s SoC	2017-01-20 21:31:34 +01:00
arm64	arm64: Work around Falkor erratum 1003	2017-02-10 11:22:12 +00:00
auxdisplay
backlight
blackfin
block	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
blockdev	scripts/spelling.txt: add "followings" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
bus-devices
cdrom	cdrom: Make device operations read-only	2017-02-14 08:29:56 -07:00
cgroup-v1	Merge branch 'for-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2017-02-27 21:41:08 -08:00
cma
connector
console
core-api	Documentation: Update CPU hotplug and move it to core-api	2017-01-13 10:32:32 -07:00
cpu-freq	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
cpuidle
cris
crypto	crypto: doc - fix typo	2017-02-15 13:23:49 +08:00
dev-tools	Improve sparse documentation	2017-02-15 15:09:13 -07:00
device-mapper	scripts/spelling.txt: add "explictely" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
devicetree	ARM: SoC: late DT updates for v4.11	2017-03-03 16:15:48 -08:00
dmaengine	dmaengine: Documentation: Fix typo in pxa_dma.txt	2016-11-14 08:14:24 +05:30
doc-guide	docs-rst: parse-headers.pl: cleanup the documentation	2016-11-30 17:08:09 -07:00
DocBook	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
driver-api	Less anger inducing pull request for 4.11	2017-02-23 18:58:18 -08:00
driver-model	irqdesc: Add a resource managed version of irq_alloc_descs()	2017-02-10 14:39:20 +01:00
early-userspace
EDID
extcon	extcon: int3496: Add Intel INT3496 ACPI device extcon driver	2017-01-09 10:04:11 +09:00
fault-injection
fb
features	2nd round of ARC udpates for 4.10rc1	2016-12-23 10:22:47 -08:00
filesystems	livepatch: add /proc/<pid>/patch_state	2017-03-08 09:38:19 +01:00
firmware_class	firmware: revamp firmware documentation	2017-01-11 09:42:59 +01:00
fmc
fpga	fpga: Add scatterlist based programming	2017-02-10 15:20:44 +01:00
frv
gpio	gpio: random documentation update	2017-01-31 15:43:05 +01:00
gpu	Less anger inducing pull request for 4.11	2017-02-23 18:58:18 -08:00
hid
hwmon	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
i2c	i2c: i801: Add support for Intel Gemini Lake	2017-02-09 17:39:16 +01:00
ia64
ide
iio
infiniband
input	Documentation: input: fix path to input code definitions	2017-02-12 15:19:00 -07:00
ioctl	rpmsg updates for v4.11	2017-02-23 09:41:03 -08:00
isdn
kbuild	Kconfig: Introduce the "imply" keyword	2016-11-16 09:26:33 +01:00
kdump
laptops	platform/x86: thinkpad_acpi: Add support for X1 Yoga (2016) Tablet Mode	2016-12-13 09:29:06 -08:00
leds	leds: class: Add new optional brightness_hw_changed attribute	2017-01-29 19:59:42 +01:00
livepatch	livepatch: allow removal of a disabled patch	2017-03-08 09:38:43 +01:00
locking	locking/ww_mutex/Documentation: Update the design document	2017-01-14 11:14:55 +01:00
m68k
md	MD: add doc for raid5-cache	2017-02-13 09:17:54 -08:00
media	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
memory-devices
metag
mic
mips
misc-devices
mmc
mn10300
mtd	spi-nor: Add support for Intel SPI serial flash controller	2017-01-03 17:33:36 +00:00
namespaces
netlabel
networking	scripts/spelling.txt: add "an user" pattern and fix typo instances	2017-02-27 18:43:46 -08:00
nfc
nios2
nvdimm
nvmem
parisc
PCI	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
pcmcia
perf	perf: add qcom l2 cache perf events driver	2017-02-08 19:32:24 +00:00
phy
platform
power	More power management updates for v4.11-rc1	2017-03-02 17:33:52 -08:00
powerpc
pps	Doc: clarify source of jitter in USB1.1, and USB2.0	2017-01-04 14:40:52 -07:00
prctl
process	Doc: Correct typo, "Introdution" => "Introduction"	2016-12-01 10:44:08 -07:00
pti
ptp
rapidio
RCU	Merge branches 'doc.2017.01.15b', 'dyntick.2017.01.23a', 'fixes.2017.01.23a', 'srcu.2017.01.25a' and 'torture.2017.01.15b' into HEAD	2017-01-25 12:56:05 -08:00
s390	Documentation: Update path to sysrq.txt	2017-03-03 15:48:38 -07:00
scheduler	sched/Documentation/sched-rt-group: Fix incorrect example	2017-01-22 10:34:17 +01:00
scsi	scripts/spelling.txt: add "varible" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
security	KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload()	2017-03-02 10:09:00 +11:00
serial
sh
sound	scripts/spelling.txt: add "followings" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
sparc	Documentation/sparc: Steps for sending break on sunhv console	2017-02-23 08:27:25 -08:00
sphinx	docs: sphinx-extensions: make rstFlatTable work with docutils 0.13	2016-12-18 13:30:29 -07:00
sphinx-static
spi	spi: spi-ep93xx: simplify GPIO chip selects	2017-02-16 20:10:26 +00:00
sysctl	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
target
thermal	Documentation: fix spelling mistakes of "Celcius" -- > "Celsius"	2017-01-04 14:36:17 -07:00
timers	time: Remove CONFIG_TIMER_STATS	2017-02-10 11:15:08 +01:00
trace	trace-vmscan-postprocess: sync with tracepoints updates	2017-02-22 16:41:29 -08:00
translations	doc/ko_KR/memory-barriers: Update control-dependencies section	2017-03-03 15:54:55 -07:00
usb	A slightly quieter cycle for documentation this time around.	2017-02-22 18:51:29 -08:00
virtual	A few fixes for the docs tree, including one for a 4.11 build regression.	2017-03-04 11:32:18 -08:00
vm	scripts/spelling.txt: add "an user" pattern and fix typo instances	2017-02-27 18:43:46 -08:00
w1
watchdog	watchdog: Introduce watchdog_stop_on_unregister helper	2017-02-24 14:00:23 -08:00
wimax
x86	Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2017-02-28 11:46:00 -08:00
xtensa
.gitignore
00-INDEX	Documentation: move MD related doc into a separate dir	2017-02-13 09:17:53 -08:00
bcache.txt
bt8xxgpio.txt
btmrvl.txt
bus-virt-phys-mapping.txt
cachetlb.txt
cgroup-v2.txt	Merge branch 'cgroup/for-4.11-rdmacg' into cgroup/for-4.11	2017-02-02 13:50:35 -05:00
Changes	docs: add back 'Documentation/Changes' file (as symlink)	2016-12-14 16:30:12 -08:00
circular-buffers.txt	Documentation: circular-buffers: use READ_ONCE()	2016-11-16 16:17:45 -07:00
clk.txt
CodingStyle
conf.py	Documentation/sphinx: fix primary_domain configuration	2017-03-03 16:12:30 -07:00
cpu-load.txt
cputopology.txt
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
digsig.txt
DMA-API-HOWTO.txt
DMA-API.txt
DMA-attributes.txt	common: DMA-mapping: add DMA_ATTR_PRIVILEGED attribute	2017-01-19 15:56:19 +00:00
DMA-ISA-LPC.txt	Documentation: DMA-ISA-LPC.txt	2017-02-12 15:20:07 -07:00
docutils.conf
dontdiff	Documentation: dontdiff: Update with additional entries	2017-01-26 15:08:06 -07:00
efi-stub.txt
eisa.txt
flexible-arrays.txt
futex-requeue-pi.txt
gcc-plugins.txt
highuid.txt
hw_random.txt
hwspinlock.txt
index.rst	docs/zh_CN: Add coding-style into docs build system	2017-01-26 15:30:34 -07:00
intel_txt.txt
Intel-IOMMU.txt
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt	Documentation: Fix a typo in IPMI.txt.	2017-01-05 15:01:54 -06:00
IRQ-affinity.txt
IRQ-domain.txt
IRQ.txt
irqflags-tracing.txt
isa.txt
isapnp.txt
kernel-doc-nano-HOWTO.txt	docs-rst: doc-guide: split the kernel-documentation.rst contents	2016-11-19 10:22:04 -07:00
kernel-per-CPU-kthreads.txt
kobject.txt
kprobes.txt
kref.txt
kselftest.txt	scripts/spelling.txt: add "an user" pattern and fix typo instances	2017-02-27 18:43:46 -08:00
ldm.txt
lockup-watchdogs.txt
logo.gif
logo.txt
lzo.txt
mailbox.txt
Makefile
Makefile.sphinx	Add a target to check broken external links in the Documentation	2017-02-15 15:22:47 -07:00
memory-barriers.txt	doc: Update control-dependencies section of memory-barriers.txt	2017-01-14 21:29:15 -08:00
memory-hotplug.txt	scripts/spelling.txt: add "followings" pattern and fix typo instances	2017-02-27 18:43:47 -08:00
men-chameleon-bus.txt
nommu-mmap.txt
ntb.txt
numastat.txt
padata.txt
parport-lowlevel.txt
percpu-rw-semaphore.txt
phy.txt
pi-futex.txt
pinctrl.txt	pinctrl: core: Fix regression caused by delayed work for hogs	2017-01-13 16:25:17 +01:00
pnp.txt
preempt-locking.txt
printk-formats.txt
pwm.txt
rbtree.txt
remoteproc.txt
rfkill.txt
robust-futex-ABI.txt
robust-futexes.txt
rpmsg.txt
rtc.txt
SAK.txt
sgi-ioc4.txt
siphash.txt	siphash: implement HalfSipHash1-3 for hash tables	2017-01-09 13:58:57 -05:00
SM501.txt
smsc_ece1099.txt
static-keys.txt	jump_label: Reduce the size of struct static_key	2017-02-15 09:02:26 -05:00
SubmittingPatches
svga.txt
sync_file.txt
this_cpu_ops.txt
unaligned-memory-access.txt	Documentation/unaligned-memory-access.txt: fix incorrect comparison operator	2016-12-27 13:08:42 -07:00
unshare.txt
vfio-mediated-device.txt	vfio-mdev: Make mdev_parent private	2016-12-30 08:13:41 -07:00
vfio.txt
video-output.txt
xillybus.txt
xz.txt
zorro.txt