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1

Very simplified: Your application wants to read a file Application asks kernel, kernel access filesystem (in kernel space ) checks permissions, handles file descriptor to application. With user space filesystems you have a lot more relatively slow kernel-to-userspace switches: Application asks kernel to open file, kernel calls userspace filesystem, ...


1

For Ubuntu, usbcore is compiled in the kernel, so create entries on /etc/modprobe.d will NOT work: we need to change the kernel boot parameters. Edit the /etc/default/grub file and change the GRUB_CMDLINE_LINUX_DEFAULT line to add the usbcore.autosuspend=-1 option: GRUB_CMDLINE_LINUX_DEFAULT="quiet splash usbcore.autosuspend=-1" Note that quit splash ...


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Since kernel 2.4 there is no difference between these cache types, there is only the page cache left.


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Get your current config.gz and deploy it in a source tree as described in this answer. Start make menuconfig and go into the "Device Drivers" submenu. Make sure "Serial ATA and Parallel ATA drivers (libata)" is disabled. Scroll down to the "USB support" sub-submenu and make sure "USB Mass Storage" is disabled. You could completely disable USB too if you ...


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As it so happens, there is another significant interface with the kernel: the /proc and /sys virtual filesystems. While they do not hold regular files, their contents are direct gateways to the kernel: to act on them is to act directly on kernel-allocated memory. For instance, if you want to drop all memory caches, you may use... echo 3 > ...


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It depends. What do you mean by 'verify'? If you just want to monitor what syscalls some process is triggering then it's possible.. usually.... But if you feel like digging deeper then you're in trouble... I have not heard of any tools that could do that. You can use strace to see what syscalls some particular process is firing. Of course you'll have to ...


0

If you don't create a configuration file of your own, then it has to be GENERIC. GENERIC is the name of the configuration file to use when setting up the kernel compilation. You can create your own kernel configuration by copying GENERIC to something else and then editing it. The you would put that name in for GENERIC. However, the OpenBSD project ...


4

I will try to answer questions as briefly as possible. The questions you are asking are usually addressed in introductory operating systems courses at universities but I will assume you have not taken such a course. Memory isolation for userspace processes is very desirable - not only to protect the kernel from malicious userspace programs, but also to ...


0

I believe this can be fixed by setting CONFIG_FW_LOADER_USER_HELPER=n and recompiling the kernel. Later kernels have this set to n by default. If this is not an option for you, try adding to /etc/udev/rules.d/50-firmware: SUBSYSTEM=="firmware", ACTION=="add", ATTR{loading}="-1" (create the file if it does not exist) and reboot. It helped for my case. ...


2

Regarding Village's Bounty, all I can find is an archived mailing list post from August, 2011 stating that the preferred default before kernel commit r225076 was 32 GB, and up to 32 Slices for a Total of 1 TB of Ram (32^2 = 1024) After r225076 the limit per slice was removed, but the thread goes on to say that the practical limit should still be considered ...


1

If a process is doing a lot of memory IO, then that will translate into using a lot of cpu time, so the scheduler will account for it, indirectly.


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Did you try the following boot parameters? i8042.reset i8042.nomux=1 psmouse.proto=imps Had a similar problem on my laptop and the problem went away with those parameters.


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If someone has physical access to your computer, they can boot from a USB key, or take out the hard drive and plug it into another computer. To prevent someone from changing boot parameters, put the computer in a locked case or locked room. If the computer is in a locked case but its keyboard is accessible to untrusted people, then you need a software means ...


2

The OpenBSD FAQ is your friend in this case. They have extensive documentation on how to build your own kernel. In particular you want section 5.3.4 but before you do that make sure and read all of section 5.3 to get a feel for the bigger picture. I'd also recommend taking a look at Absolute OpenBSD by Michael Lucas. He's got a pretty good walk through on ...


0

I haven't seen an explicit statement about that and I haven't given it a try but I guess this is not necessary. In addition to my guess the man pages says: kexec performs the function of the boot loader from within the kernel. An adaption of the kernel to be loaded would be necessary only if some black magic instead of the boot loader procedure was ...


0

This message is what it looks like: it's the indication of a bug. Specifically, it comes from the Linux kernel. It's a fairly generic symptom of a badly-written driver. This bug indicates a kernel bug: nothing outside the kernel can cause this to happen unless the kernel is buggy in the first place. The only other possibility is a hardware failure: bad RAM ...


1

Turns out to be a false warning. To quote from the (now closed) kernel bug report: Alfred Krohmer: If I unterstand your patch correctly it just removes the warning, but it won't actually fix the driver crash this bug report was submitted for. So why mark it as resolved? Emmanuel Grumbach: There is no real bug. The commit message explains this. ...


0

To trace which processes consume inotify watches (not instances) you can use the dynamic ftrace feature of the kernel if it is enabled in your kernel. The kernel option you need is CONFIG_DYNAMIC_FTRACE. First mount the debugfs filesystem if it is not already mounted. mount -t debugfs nodev /sys/kernel/debug Go under the tracing subdirectory of this ...


1

As it turns out, it seems the underlying issue was not having the right proprietary drivers installed for my nVidia graphics card. I was under the presumption that I had to use nVidia's driver installer, but installing the right packages from RPMFusion and disabling Nouveau worked perfectly. Since installing the necessary drivers, my system is running ...


4

These are Long Term Releases: There are usually several "longterm maintenance" kernel releases provided for the purposes of backporting bugfixes for older kernel trees. Only important bugfixes are applied to such kernels and they don't usually see very frequent releases, especially for older trees. Source: https://www.kernel.org/releases.html


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LTR stands for Long Term Release. This is also known as a LTSR, short for Long Term Support Release. These releases are supported for a longer time, and are meant to be used in Production Environments, where stability is preferred over new features. In terms of the kernel you are reading about, the LTR cycle is about 3 years. This means if you are a user ...


0

I'm not sure if this is the same problem I had or not, but I recently upgraded and old internal DNS server system from OpenBSD 3.8 to 5.6, and I lost the ability to resolve hosts with ping, but the host command was working. Turned out I had to add 127.0.0.1/8 to the match-clients directive in named in addition to the 192.168.0.0/16 which I already had there, ...


1

In both cases those are not primarily warnings that break the build. For the kernel compilation: error: 'struct run_vap' has no member named 'beacon_mbuf' the compiler tells you, that the code is trying to access something that isn't there. This may have many reasons, but generally it suggests that the code is broken. Maybe you are trying to compile a ...


3

The premise is unprovable. Science requires a falsifiable hypothesis; there is no way to test any of the likely counterhypotheses, such as that Windows would crash less if Apple wrote all of the drivers instead, or that Windows would be more stable if Microsoft somehow cut off support for a vast chunk of the existing supported hardware space. You'd basically ...


0

No, you don't have to change any script. It seems like your Buildroot configuration is incorrect, but since you didn't provide your config, there's no real way to give a precise answer. Can you run make savedefconfig and post the output of this file here? Basically, what Buildroot is complaining about here is a mismatch between the kernel headers version it ...


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AFAIK, editing /boot.cfg is the preferred method. You can even specify more human-readable modes; I am using (on -current, 7.99 in a VirtualBox VM) menu=Boot normally:rndseed /var/db/entropy-file:;vesa 1024x768x32; boot netbsd I think having this in the kernel somehow without it being compiled in would be bad - if you update your kernel you'd lose the ...


0

Starnamer is correct (I was one of the beta testers). Putting it in the kernel was an attempt to improve abysmal performance (mainly to PCNFS clients) and once that issue was solved noone looked at it much again. There are a number of deficiencies with having NFS in the kernel, not least of which is that it doesn't play nicely with anything else touching ...



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