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
DocBook	Merge tag 'drm-for-v4.8' of git://people.freedesktop.org/~airlied/linux	2016-08-01 21:44:08 -04:00
EDID	…
PCI	…
RCU	Documentation: Fix spelling mistake	2016-06-14 16:01:00 -07:00
accounting	…
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	…
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
driver-model	ARM: SoC driver updates for v4.8	2016-08-01 18:36:01 -04:00
early-userspace	…
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	…
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	…
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	…
ja_JP	…
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	…
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	…
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	…
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	…
pcmcia	…
phy	…
platform	…
power	…
powerpc	…
pps	…
prctl	…
pti	…
ptp	…
rapidio	…
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	…
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	…
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
BUG-HUNTING	…
Changes	…
CodeOfConflict	…
CodingStyle	docs: deprecate kernel-doc-nano-HOWTO.txt	2016-07-20 16:45:37 -06:00
DMA-API-HOWTO.txt	…
DMA-API.txt	…
DMA-ISA-LPC.txt	…
DMA-attributes.txt	…
HOWTO	…
IPMI.txt	…
IRQ-affinity.txt	…
IRQ-domain.txt	…
IRQ.txt	…
Intel-IOMMU.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	…
SAK.txt	…
SM501.txt	…
SecurityBugs	…
SubmitChecklist	…
SubmittingDrivers	…
SubmittingPatches	…
VGA-softcursor.txt	…
adding-syscalls.txt	…
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	…
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	…
circular-buffers.txt	…
clk.txt	…
coccinelle.txt	…
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	…
digsig.txt	…
dma-buf-sharing.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	…
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	…
io-mapping.txt	…
io_ordering.txt	…
iostats.txt	…
irqflags-tracing.txt	…
isa.txt	…
isapnp.txt	…
java.txt	…
kasan.txt	…
kcov.txt	…
kernel-doc-nano-HOWTO.txt	docs: deprecate kernel-doc-nano-HOWTO.txt	2016-07-20 16:45:37 -06:00
kernel-docs.txt	…
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	…
ldm.txt	…
local_ops.txt	…
lockup-watchdogs.txt	…
logo.gif	…
logo.txt	…
lzo.txt	…
magic-number.txt	…
mailbox.txt	…
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	…
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	…
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	…
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	…
robust-futex-ABI.txt	…
robust-futexes.txt	…
rpmsg.txt	rpmsg: use module_rpmsg_driver in existing drivers and examples	2016-05-06 11:09:01 -07:00
rtc.txt	…
serial-console.txt	…
sgi-ioc4.txt	…
smsc_ece1099.txt	…
sparse.txt	…
stable_api_nonsense.txt	…
stable_kernel_rules.txt	…
static-keys.txt	…
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	…
this_cpu_ops.txt	…
ubsan.txt	…
unaligned-memory-access.txt	…
unicode.txt	…
unshare.txt	…
vfio.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	…
xz.txt	…
zorro.txt	…