Borislav Petkov 750afe7bab printk: add kernel parameter to control writes to /dev/kmsg ... Add a "printk.devkmsg" kernel command line parameter which controls how userspace writes into /dev/kmsg. It has three options: * ratelimit - ratelimit logging from userspace. * on - unlimited logging from userspace * off - logging from userspace gets ignored The default setting is to ratelimit the messages written to it. This changes the kernel default setting of "on" to "ratelimit" and we do that because we want to keep userspace spamming /dev/kmsg to sane levels. This is especially moot when a small kernel log buffer wraps around and messages get lost. So the ratelimiting setting should be a sane setting where kernel messages should have a bit higher chance of survival from all the spamming. It additionally does not limit logging to /dev/kmsg while the system is booting if we haven't disabled it on the command line. Furthermore, we can control the logging from a lower priority sysctl interface - kernel.printk_devkmsg. That interface will succeed only if printk.devkmsg *hasn't* been supplied on the command line. If it has, then printk.devkmsg is a one-time setting which remains for the duration of the system lifetime. This "locking" of the setting is to prevent userspace from changing the logging on us through sysctl(2). This patch is based on previous patches from Linus and Steven. [bp@suse.de: fixes] Link: http://lkml.kernel.org/r/20160719072344.GC25563@nazgul.tnic Link: http://lkml.kernel.org/r/20160716061745.15795-3-bp@alien8.de Signed-off-by: Borislav Petkov <bp@suse.de> Cc: Dave Young <dyoung@redhat.com> Cc: Franck Bui <fbui@suse.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2016-08-02 19:35:06 -04:00
..
ABI	Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next	2016-07-27 12:03:20 -07:00
accounting	taskstats: fix nl parsing in accounting/getdelays.c	2016-04-27 12:50:14 -04:00
acpi	Merge branches 'acpi-bus', 'acpi-pci', 'acpica' and 'acpi-doc'	2016-07-25 13:41:25 +02:00
aoe
arm	ARM: at91: Documentation: update the sama5d2 entry	2016-06-21 17:09:34 +02:00
arm64	ARM64: ACPI: Update documentation for latest specification version	2016-06-21 16:26:09 +01:00
auxdisplay
backlight
blackfin
block	Merge branch 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2016-07-28 12:59:05 -07:00
blockdev	zram: cosmetic: cleanup documentation	2016-07-26 16:19:19 -07:00
bus-devices
cdrom
cgroup-v1	mm, vmscan: move lru_lock to the node	2016-07-28 16:07:41 -07:00
cma
connector	samples: connector: from Documentation to samples directory	2016-04-28 07:47:35 -06:00
console
cpu-freq	Revert "cpufreq: pcc-cpufreq: update default value of cpuinfo_transition_latency"	2016-07-22 23:51:06 +02:00
cpuidle
cris
crypto	crypto: doc - Fix typo	2016-05-31 16:41:55 +08:00
development-process	docs: deprecate kernel-doc-nano-HOWTO.txt	2016-07-20 16:45:37 -06:00
device-mapper	dm raid: update Documentation about reshaping/takeover/additonal RAID types	2016-06-14 18:52:12 -04:00
devicetree	Merge tag 'drm-for-v4.8' of git://people.freedesktop.org/~airlied/linux	2016-08-01 21:44:08 -04:00
dmaengine	Documentation: dmaengine: fix typo for device_resume	2016-06-03 14:00:21 -06:00
DocBook	Merge tag 'drm-for-v4.8' of git://people.freedesktop.org/~airlied/linux	2016-08-01 21:44:08 -04:00
driver-model	ARM: SoC driver updates for v4.8	2016-08-01 18:36:01 -04:00
early-userspace
EDID
extcon
fault-injection
fb	Documentation: fb: fix spelling mistakes	2016-05-10 12:05:27 +03:00
features	powerpc: Add HAVE_PERF_USER_STACK_DUMP support	2016-05-11 21:54:05 +10:00
filesystems	libnvdimm for 4.8	2016-07-28 17:38:16 -07:00
firmware_class	Documentation: fix common spelling mistakes	2016-04-28 07:51:59 -06:00
fmc
fpga
frv
gpio	gpio: Fix paths to GPIO driver source files	2016-06-13 09:30:31 +02:00
gpu	drm/doc: Spinx leftovers	2016-07-19 14:12:00 +02:00
hid	HID: add Alps I2C HID Touchpad-Stick support	2016-06-17 23:12:04 +02:00
hwmon	hwmon: Add driver for FTS BMC chip "Teutates"	2016-07-20 06:29:54 -07:00
i2c	Documentation: i2c: slave: give proper example for pm usage	2016-07-23 22:04:20 +02:00
ia64
ide
iio
infiniband	Round two of 4.7 merge window patches	2016-05-28 11:04:16 -07:00
input	Input: clarify we want BTN_TOOL_<name> on proximity	2016-04-06 10:23:09 -07:00
ioctl	Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security	2016-07-29 17:38:46 -07:00
isdn	isdn: i4l: move active-isdn drivers to staging	2016-03-05 15:00:38 -08:00
ja_JP	Documentatio: HOWTO: remove regression postings info from translations	2016-04-16 10:49:08 -06:00
kbuild	kbuild, x86: Track generated headers with generated-y	2016-07-07 15:58:44 +02:00
kdump	kdump: fix dmesg gdbmacro to work with record based printk	2016-06-03 15:06:22 -07:00
ko_KR	Documentation: HOWTO: update git home URL in translations	2016-04-16 10:49:18 -06:00
laptops	leds: documentation: 'ide-disk' to 'disk-activity'	2016-06-27 08:58:35 +02:00
leds	leds: documentation: 'ide-disk' to 'disk-activity'	2016-06-27 08:58:35 +02:00
livepatch	Merge branches 'for-4.7/core', 'for-4.7/livepatching-doc' and 'for-4.7/livepatching-ppc64' into for-linus	2016-05-17 12:06:35 +02:00
locking	locking/Documentation/lockdep: Fix spelling mistakes	2016-04-28 10:40:57 +02:00
m68k
media	[media] cx23885-cardlist.rst: add a new card	2016-07-23 08:14:48 -03:00
memory-devices
metag
mic	mpssd: fix buffer overflow warning	2016-06-03 13:31:37 -06:00
mips
misc-devices	Merge char-misc-next into staging-next	2016-02-22 14:46:24 -08:00
mmc	mmc: core: Extend sysfs with DSR register	2016-07-25 10:34:51 +02:00
mn10300
mtd
namespaces
netlabel
networking	Documentation: RDS: Document Multipath RDS (mprds)	2016-07-15 11:36:58 -07:00
nfc
nios2
nvdimm	libnvdimm, btt: update the usage section in Documentation	2016-06-17 16:23:23 -07:00
nvmem
parisc
PCI
pcmcia
phy
platform
power	PM / runtime: Document steps for device removal	2016-04-05 03:46:59 +02:00
powerpc	powerpc/eeh: rename EEH from "extended" to "enhanced" error handling	2016-04-11 20:30:42 +10:00
pps	Documentation: pps: fix spelling mistake	2016-04-28 07:23:59 -06:00
prctl	Documentation: Fix int/unsigned int comparison	2016-02-17 14:09:43 -07:00
pti
ptp	Another relatively boring cycle for the docs tree: typo fixes, translation	2016-03-17 12:09:35 -07:00
rapidio	rapidio: add mport char device driver	2016-03-22 15:36:02 -07:00
RCU	Documentation: Fix spelling mistake	2016-06-14 16:01:00 -07:00
s390	s390/Documentation: improve sort command for trace buffer	2016-06-13 15:58:23 +02:00
scheduler
scsi	Merge remote-tracking branch 'mkp-scsi/4.7/scsi-fixes' into fixes	2016-06-18 11:59:01 -07:00
security	Some big changes this month, headlined by the addition of a new formatted	2016-07-26 13:05:11 -07:00
serial	TTY and Serial driver update for 4.7-rc1	2016-05-20 20:57:27 -07:00
sh
sound	ASoC: Updates for v4.8	2016-07-26 10:35:31 +02:00
sphinx	Merge branch 'docs-next' of git://git.lwn.net/linux into topic/docs-next	2016-07-23 07:55:59 -03:00
sphinx-static	[media] doc-rst: backward compatibility with older Sphinx versions	2016-07-19 12:35:08 -03:00
spi
sysctl	printk: add kernel parameter to control writes to /dev/kmsg	2016-08-02 19:35:06 -04:00
target	target: make close_session optional	2016-05-10 01:19:26 -07:00
thermal	Doc: PM: Fix a typo in intel_powerclamp.txt	2016-06-30 13:05:40 -06:00
timers	Documentation: fix common spelling mistakes	2016-04-28 07:51:59 -06:00
tpm	tpm: Add documentation for the tpm_vtpm_proxy device driver	2016-06-25 17:26:35 +03:00
trace	tracing: expose current->comm to [ku]probe events	2016-06-20 09:54:19 -04:00
usb	Documentation: tiny typo fix in usb/gadget_multi.txt	2016-06-23 08:09:10 -06:00
vDSO
virtual	kvm: introduce KVM_MAX_VCPU_ID	2016-05-11 22:37:54 +02:00
vm	mm: fix build warnings in <linux/compaction.h>	2016-07-26 16:19:19 -07:00
w1	w1: add ability to set (SRAM) and store (EEPROM) configuration for temp sensors like DS18B20	2016-05-01 14:37:49 -07:00
watchdog	Documentation/watchdog: check return value for magic close	2016-07-25 11:02:17 +02:00
wimax
x86	Merge branch 'linus' into x86/microcode, to pick up merge window changes	2016-07-27 12:35:35 +02:00
xtensa
zh_CN	docs: deprecate kernel-doc-nano-HOWTO.txt	2016-07-20 16:45:37 -06:00
.gitignore	Add .pyc files to .gitignore	2016-06-30 13:07:33 -06:00
00-INDEX	docs: deprecate kernel-doc-nano-HOWTO.txt	2016-07-20 16:45:37 -06:00
adding-syscalls.txt	documentation: trivial typo: adding-syscalls.txt: s/statat/fstatat/	2016-04-18 11:31:49 -06:00
applying-patches.txt
assoc_array.txt
atomic_ops.txt
bad_memory.txt
basic_profiling.txt
bcache.txt	bcache: documentation formatting, edited for clarity, stripe alignment notes	2016-06-23 07:58:38 -06:00
binfmt_misc.txt
braille-console.txt
bt8xxgpio.txt
btmrvl.txt
BUG-HUNTING
bus-virt-phys-mapping.txt
cachetlb.txt
cec.txt	[media] cec.txt: add CEC framework documentation	2016-06-22 08:36:50 -03:00
cgroup-v2.txt	Merge branch 'for-4.6-ns' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2016-03-21 10:05:13 -07:00
Changes
circular-buffers.txt
clk.txt
coccinelle.txt
CodeOfConflict
CodingStyle	docs: deprecate kernel-doc-nano-HOWTO.txt	2016-07-20 16:45:37 -06:00
conf.py	Revert "doc/sphinx: Enable keep_warnings"	2016-07-20 16:56:21 -06:00
cpu-hotplug.txt
cpu-load.txt
cputopology.txt	topology/sysfs: provide drawer id and siblings attributes	2016-06-13 15:58:27 +02:00
crc32.txt
dcdbas.txt
debugging-modules.txt
debugging-via-ohci1394.txt
dell_rbu.txt
devices.txt	Documentation: update the devices.txt documentation	2016-03-29 10:11:44 -07:00
digsig.txt
DMA-API-HOWTO.txt	dma-mapping: always provide the dma_map_ops based implementation	2016-01-20 17:09:18 -08:00
DMA-API.txt
DMA-attributes.txt	ARM: 8506/1: common: DMA-mapping: add DMA_ATTR_ALLOC_SINGLE_PAGES attribute	2016-02-11 15:33:38 +00:00
dma-buf-sharing.txt	dma-buf: Update docs for SYNC ioctl	2016-03-21 09:26:45 +01:00
DMA-ISA-LPC.txt
dontdiff
dynamic-debug-howto.txt
edac.txt
efi-stub.txt
eisa.txt
email-clients.txt
flexible-arrays.txt
futex-requeue-pi.txt
gcov.txt
gdb-kernel-debugging.txt	Revert "scripts/gdb: add documentation example for radix tree"	2016-07-15 14:54:27 +09:00
highuid.txt
HOWTO	Documentation: Howto: Fixed subtitles style	2016-03-09 15:30:03 -07:00
hsi.txt
hw_random.txt
hwspinlock.txt
index.rst	Merge tag 'drm-for-v4.8' of git://people.freedesktop.org/~airlied/linux	2016-08-01 21:44:08 -04:00
init.txt
initrd.txt
intel_txt.txt
Intel-IOMMU.txt	iommu/vt-d: Fix link to Intel IOMMU Specification	2016-01-29 12:32:12 +01:00
io_ordering.txt
io-mapping.txt
iostats.txt
IPMI.txt
IRQ-affinity.txt
IRQ-domain.txt	Documentation/IRQ-domain.txt: Document irq_domain_create_{linear, tree}	2016-03-31 00:32:59 -06:00
IRQ.txt
irqflags-tracing.txt
isa.txt	Documentation: Add ISA bus driver documentation	2016-05-02 09:32:04 -07:00
isapnp.txt
java.txt
kasan.txt	mm, kasan: SLAB support	2016-03-25 16:37:42 -07:00
kcov.txt	kernel: add kcov code coverage	2016-03-22 15:36:02 -07:00
kernel-doc-nano-HOWTO.txt	docs: deprecate kernel-doc-nano-HOWTO.txt	2016-07-20 16:45:37 -06:00
kernel-docs.txt	Documentation: update Michael K. Johnson's work	2016-04-15 15:37:25 -06:00
kernel-documentation.rst	docs: Get rid of some kernel-documentation warnings	2016-07-17 19:24:02 -06:00
kernel-parameters.txt	printk: add kernel parameter to control writes to /dev/kmsg	2016-08-02 19:35:06 -04:00
kernel-per-CPU-kthreads.txt
kmemcheck.txt
kmemleak.txt
kobject.txt
kprobes.txt
kref.txt
kselftest.txt	Documentation: kselftest: Remove duplicate word	2016-03-09 15:33:38 -07:00
ldm.txt
local_ops.txt
lockup-watchdogs.txt
logo.gif
logo.txt
lzo.txt	Documentation: lzo: fix spelling mistakes	2016-04-28 07:23:11 -06:00
magic-number.txt
mailbox.txt
Makefile	[media] samples: v4l: from Documentation to samples directory	2016-05-09 18:34:37 -03:00
Makefile.sphinx	Merge branch 'docs-next' of git://git.lwn.net/linux into devel/docs-next	2016-07-15 07:33:47 -03:00
ManagementStyle
md-cluster.txt	md-cluster: change array_sectors and update size are not supported	2016-05-04 12:39:35 -07:00
md.txt	Documentation: fix wrong value in md.txt	2016-06-23 08:08:36 -06:00
memory-barriers.txt	locking/Documentation: Clarify limited control-dependency scope	2016-06-17 09:54:45 +02:00
memory-hotplug.txt	memory_hotplug: introduce CONFIG_MEMORY_HOTPLUG_DEFAULT_ONLINE	2016-05-19 19:12:14 -07:00
men-chameleon-bus.txt
module-signing.txt	modsign: Fix documentation on module signing enforcement parameter.	2016-03-12 01:48:11 -07:00
mono.txt
nommu-mmap.txt
ntb.txt
numastat.txt
oops-tracing.txt
padata.txt
parport-lowlevel.txt
parport.txt
percpu-rw-semaphore.txt
phy.txt	phy: core: Allow children node to be overridden	2016-04-29 16:39:39 +02:00
pi-futex.txt
pinctrl.txt	pinctrl: Flag strict is a field in struct pinmux_ops	2016-06-23 10:50:10 +02:00
pnp.txt
preempt-locking.txt
printk-formats.txt	mm, printk: introduce new format string for flags	2016-03-15 16:55:16 -07:00
pwm.txt	pwm: Update documentation	2016-05-17 14:48:04 +02:00
ramoops.txt	pstore/ram: add Device Tree bindings	2016-06-14 11:34:39 -07:00
rbtree.txt
remoteproc.txt
rfkill.txt	rfkill: Add documentation about LED triggers	2016-02-24 09:13:12 +01:00
robust-futex-ABI.txt
robust-futexes.txt	Documentation: robust-futexes: fix spelling mistakes	2016-04-28 07:26:41 -06:00
rpmsg.txt	rpmsg: use module_rpmsg_driver in existing drivers and examples	2016-05-06 11:09:01 -07:00
rtc.txt	rtc: implement a sysfs interface for clock offset	2016-03-14 17:08:16 +01:00
SAK.txt
SecurityBugs
serial-console.txt
sgi-ioc4.txt
SM501.txt
smsc_ece1099.txt
sparse.txt
stable_api_nonsense.txt
stable_kernel_rules.txt
static-keys.txt
SubmitChecklist
SubmittingDrivers
SubmittingPatches	SubmittingPatches: fix spelling of "git send-email"	2016-01-25 12:30:18 -07:00
svga.txt
sync_file.txt	Documentation: Fix some grammar mistakes in sync_file.txt	2016-06-03 13:24:16 -06:00
sysfs-rules.txt
sysrq.txt	Doc: correct the location of sysrq.c	2016-04-28 08:02:36 -06:00
this_cpu_ops.txt
ubsan.txt	UBSAN: run-time undefined behavior sanity checker	2016-01-20 17:09:18 -08:00
unaligned-memory-access.txt
unicode.txt
unshare.txt
vfio.txt
VGA-softcursor.txt
vgaarbiter.txt
video-output.txt
vme_api.txt
volatile-considered-harmful.txt
workqueue.txt	workqueue: Fix a typo in workqueue.txt	2016-07-06 02:37:38 -06:00
xillybus.txt	Documentation: xillybus: fix spelling mistake	2016-04-28 07:44:54 -06:00
xz.txt
zorro.txt