Questions tagged [kernel]

The core part of an operating system, responsible for managing resource allocation.

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4answers
119 views

How to find cause of high kernel_task cpu usage?

Occasionally my machine will have a kernel_task instance max out the CPU: This can last from minutes to sometimes hours. The machine is effectively unusable in this state. Restarting doesn't help; a ...
8
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0answers
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Does macOS still use Yarrow as it's cryptographically secure pseudorandom number generator?

I'm trying to understand if the XNU underpinnings of macOS (BSD) still use the Yarrow cryptographically secure pseudorandom number generator? I have looked through the source and it seems as if they ...
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2answers
40 views

MacBook without battery kernel_task 100% CPU utilization

After removing the battery from a MacBook late 2009 following a battery fault, the computer always runs kernel_task at 100% CPU utilization. I assume the process ends up in some kind of spin lock when ...
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0answers
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iMac: How to disable display via terminal. Kernel_task issue CPU 70%

I have a Late 2015 iMac running macOS Mojave. I am looking to disable the main display and use an external display as the primary/default display. I am looking for a command-line that can do that. I ...
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0answers
20 views

Generating NMI (non-maskable interrupt) in Mac VM running on VMware Fusion

I'm trying to (kernel-)debug my Mac 10.14.5 VM running on VMWare Fusion (v11.0.2) on my Mac 10.13.6 host. I'm following documentation/blogs in [1], [2]. I am trying to generate an NMI (non-maskable ...
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0answers
175 views

Device Console error: kernel compat_ifmu_ulist error 14

After looking through my Console log I noticed a strange error that seems to show up around 10 times a second or so. The error is coming from the kernel and shows up as one of the following 5 or so ...
1
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1answer
28 views

`dtrace_deadman_timeout` modification for dtrace scripts such as dtruss?

When running some intensive debugging that needs to run on the order of about 5 minutes, I'm finding that dtrace's deadman switch is being triggered regularly and cannot get to the error that is being ...
2
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2answers
128 views

How to limit kernel_tasks CPU usage?

I would like to limit kernel_task's CPU usage on my computer. I provided cooling for my MacBook Pro, cleaned out the internals, and tried resetting the SMC multiple times. I haven't tried re-...
1
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0answers
187 views

What is kernel_task writing and reading?

After moving from High-Sierra to Mojave I noticed my Mac (23", fusion-drive 3.4GHz) has become much slower. In particular, I noticed that just after the startup I have a significant amount of disk ...
1
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3answers
86 views

grep command is killed

I am running grep -o $string ~/giant_file where string="foo bar baz" This process keeps being killed after running for awhile and generating results, and I don't understand why. When it is killed, ...
4
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5answers
8k views

macOS Sierra, kernel_task running taking more than 400% of CPU

After upgrading my MacBookPro to macOS Sierra, CPU is running very fast. When I tried to debug the issue, here is what I have found. Solutions that I have already tried. Reset SMC Reset PRAM Tried ...
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1answer
119 views

Why is Mac OSX temp. directory in weird path

Comparing to Linux systems OSX default temporary directory seems to be in a weird path. I want to know why that is, at least how is this organized. Here are my observations: My echo "$TMPDIR" ...
1
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1answer
339 views

How to remove all traces of a kext?

I am trying to fully remove a kernel extension which I installed by mistake, and I can't figure out how to remove it from the Disabled Software list. It appears in System Profiler and also in System ...
0
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1answer
57 views

Problem with kernel_task

It's about 3 days that I can't do anything with my macbook air because the kernel_task is eating up the CPU. So I found this but the command csrutil disable/enable doesn't work on the terminal (El ...
0
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1answer
81 views

What is the purpose of speculative memory?

Recently, I've found out that Darwin has speculative memory metric. But, I don't know what the purpose of speculative memory. The memory metric can be checked using vm_stat command on terminal. Mach ...
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1answer
107 views

Why do most processes run as children of launchd?

When did most processes run as a child of launchd instead of the kernel pid ?
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2answers
3k views

Is it theoretically possible for DirectX to work on OS X natively?

As far as I can tell, DX as a software-component is tightly wound to Windows as for hardware-acceleration and is provided as a set of DLLs and a runtime system for applications that depend on it; ...
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3answers
8k views

Where to see kernel startup messages after boot?

I set my kernel to boot up verbose using sudo nvram boot-args="-v" These logs are what I wanted to see, but how can I view the log after booting? I searched all log files without success.
1
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1answer
1k views

Mac Mini - New SSD - Randomly restarting

I've had my 2011 Mac Mini for a while. About a year ago the internal HDD decided to give up. Oh well. I just now finally got around to being able to replace the hard drive. I decided to go with an ...
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0answers
241 views

Kernel panics due to Parallels Desktop or Apple's own problem with graphics controller?

Twice this week my MacBook Pro Retina has suffered kernel panics for the first time after years of faithful service. This coincides with me upgrading and beginning to use Parallels 14.0.1, so I ...
3
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2answers
469 views

Where can I find Mojave Kernel Headers?

I'm trying to get a hold of the Kernel Headers for 10.14 Mojave, but even though the Beta version (even two actually) was already released, XNU's repository (both here and here) is still only up-to-...
3
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1answer
976 views

Macbook pro wont boot, Kernel cache read error 0x6

I have recently installed macOS Sierra and sometimes my Macbook pro mid-2012 boots up properly (rarely). Otherwise it does not boot. When I try to boot it with cmd+v , it shows following text: Read ...
5
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1answer
81 views

What is this security feature called?

What is this "System software from developers" security feature called and where can I find the technical details for how it works with applications (like AVG)? I believe this is a kernel extension, ...
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0answers
36 views

Dtrace working but no kernel data can be output?

I have for a long time run as sip -without dtrace to use dtrace and this is fine but a few apps I want to read data from seen to run in kernel mode (Little Snitch has several components for instance). ...
5
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0answers
193 views

Fake ethernet interfaces (feth / if_fake)? Anyone ever seen this?

I've been digging into Darwin source to try to find some way to create virtual Ethernet interfaces on Mac/Darwin without adding a kernel extension like tuntaposx. In doing so I've found something ...
3
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2answers
851 views

High Sierra restored from ISO to USB drive stops at the stop sign

I've restored macOS High Sierra ISO file (downloaded from Torrent) to pendrive (16GB SanDisk's Cruzer Dial) using Disk Utility, however when booting from it (by pressing Alt and selecting the drive), ...
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1answer
3k views

Free up unused memory from kernel_task

I am a web developer, and sometimes I encounter software bugs that has runaway threads or used up available memory in a browser process. Terminating the offending Chrome process will free up the ...
3
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1answer
2k views

Is it safe to quit kernel_task?

I recently quit kernel_task because it was taking a lot of cpu time, when I was about to force quit it it says you will be logged out but I did not care but then after I force quit it I thought does ...
46
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3answers
13k views

AppleCare engineer says Macs need weekly reboots b/c “kernel expires”. What's that mean?

I'm running MacOS Sierra on a mid-2014 MacBook Pro. About once/week, Safari’s CPU usage becomes very high, and it becomes very laggy. In the last instance I had just six windows open, none of which ...
0
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1answer
397 views

Macbook pro touch bar spoiled with kernel panics [duplicate]

After dropping my macbook pro, my touch bar has stopped working and I am getting frequent kernel panics Does anyone have any idea how to solve this or which part of the macbook is faulty? Thank you!...
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3answers
1k views

High Sierra: WindowManager and kernel_task - Now you see it, now you don't!

I have long had issues with both Window Manager and kernel_task taking up seemingly inordinate amounts of resources on my systems going back in the OS release cycle for as long as I can remember, but ...
3
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0answers
598 views

kernel_task writes huge amounts of data to disk (> 1TB) - how to diagnose?

My MacBook (2016 with TouchBar) running macOS 10.13 has a 512GB SSD. Looking at the activity monitor after a couple of weeks of uptime (most of it spent in standby), kernel_task shows 1.43TB (!) of ...
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0answers
75 views

Kernel_Task using too much RAM [duplicate]

ever since updating my mac to high sierra my kernel_task has been using way too much RAM up to 1gb (i have 4 gb of RAM). Any solutions on how to resolve this?
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2answers
2k views

How to access /dev/mem in OSX?

How I can access /dev/mem (or /dev/kmem, /dev/pmap) equivalent device in OSX? As far as I know it was removed in some point. Can I create this node manually somehow or any other way of dumping the ...
129
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2answers
177k views

How to investigate high kernel task memory usage?

I was using my MBP (with 16GB of RAM) as usual and out of blue I've this popup that: Your system has run out of application memory. To avoid problems with your computer, quit any applications ...
4
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1answer
3k views

What's a normal value for kernel_task RAM usage?

Just bought a new MacBook Pro 12.1, early 2015 (Yosemite 10.10.4). I'm observing memory usage from kernel_task varying between 0.8-2.0 GB. Is it normal? Couldn't find a question referring to normal ...
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3answers
56k views

What exactly does kernel_task do?

I'd just like to know what it is that kernel_task is responsible for. Also, what's an acceptable maximum RAM and CPU use for it?
2
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1answer
2k views

How to view the kernel on MacOS?

How to view the kernel on MacOS? I am learning Linux command line by William Shotts, The Kernal directory can been accessed by : ls /bin # Contain Linux kernal, inital RAM disk image How to view ...
4
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1answer
1k views

MacBook unusable due to kernel_task

I've disabled hibernation, and removed the sleep image file. I shutdown my Macbook Pro (15" retina), unticked the box to open windows on restart, and started my MacBook again. As soon as I'd logged on ...
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0answers
268 views

Kernel Panic Once A Week

I get the exact same kernel panic on my iMac 5K Late 2014 Edition pretty much once a week. Does anyone know what is causing it? Anonymous UUID: F36129E9-69E1-B321-06F7-0519199C40B7 Tue Mar 6 ...
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0answers
83 views

That Kernel Process Bloat

This is probably a question best suited for Apple Support Forums, but after asking variants of this question there to no avail, I will try here instead. I have a 2012/2013 2.3 GHz i7 Mac Mini w/ 16 ...
0
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1answer
37 views

Kernel Error screen

I have an older Macbook Pro which I haven't used much lately since purchasing a new Macbook Pro. The older one was near capacity and would get very hot. I could still turn it on and look for things ...
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3answers
7k views

How to properly increase a `ulimit -n` limits?

I'm trying to download the X-Plane 10 Demo through uTorrent, however I get a "too many open files" error all the time. I can do the alternate download (which takes forever and a day), but I wonder how ...
19
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4answers
11k views

Which command controls the open file limits?

Which command / configuration file controls the open file limits on OS X? Is there a different command for OS X 10.5 / 10.6 / 10.7? The options I explore below are ulimit, sysctl, and launchctl "...
9
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1answer
12k views

Sleep Wake Failures because of watchdog on 10.13 (supplemental update)

I have experienced this twice in the last 48 hours, both occurring around the same time. Are the times correlated or coincidence? Can anyone shed some light on this for me? Relevant lines from system....
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2answers
284 views

A question about installing kernels (related to running Hydrogen with Atom)

I have a really basic question, but the more I read, the more confused I get: How do I install pip so I can install kernels? This question came about when I tried to install the Hydrogen package to ...
3
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1answer
2k views

Console Message: “kernel: Sandbox: net.conceited.Ru System Policy: deny(1) mach-priv-task-port 391”

I'm getting about 50 messages like the following on the console every second. 01/09/15 17:50:32,000 kernel[0] Sandbox: net.conceited.Ru(295) System Policy: deny(1) mach-priv-task-port 402 01/09/...
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3answers
11k views

What is a Kernel Panic and what does it mean?

I have this report: Anonymous UUID: Removed Tue Aug 11 20:26:13 2015 *** Panic Report *** panic(cpu 2 caller 0xffffff8028bc1cde): "launchd died\nState at Last Exception:\n\n"@/SourceCache/xnu/...
4
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1answer
905 views

How to debug “too many open files”?

I have a program that quits after a time with "too many open files". How can I trace which files are opened and closed? I know I can set this limit a higher value, but that would only defer the ...
6
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1answer
3k views

CPU stuck at 0.8Ghz on iMac late 2013 2.7Ghz because of kernel_task

I know it seems like this question is like the dozens of other questions about CPU overheating and kernel_task overloading it, but nope. I found an iMac (yep, found it. In the trash). I fixed it (...