linux-kernel

问题 My question has roughly been discussed here. And the tl;dr solution is to do: iptables -A OUTPUT -p tcp --tcp-flags RST RST -j DROP And you could modify this to only block the port you're actively listening after. But as mentioned in the above question, and here, these are not elegant solutions. Now, I don't really care about the elegance of things. But I do care about learning. So I've dug deep into the Linux source code (mostly interested in Linux based machines for now) and sorted through

问题 I tried setting Linux kernel. After editing /etc/sysctl.conf and executing the sysctl -p it shows error Invalid argument" setting key "net.core.somaxconn" Linux distribution: Ubuntu 12.04.4 LTS, x86_64, 3.2.0-60-generic $ cat /etc/sysctl.conf net.ipv4.conf.eth0.arp_notify = 1 vm.swappiness = 0 net.ipv4.tcp_rmem = 4096 87380 4194304 net.ipv4.tcp_wmem = 4096 16384 4194304 net.core.wmem_default = 8388608 net.core.rmem_default = 8388608 net.core.rmem_max = 16777216 net.core.wmem_max = 16777216

问题 I tried setting Linux kernel. After editing /etc/sysctl.conf and executing the sysctl -p it shows error Invalid argument" setting key "net.core.somaxconn" Linux distribution: Ubuntu 12.04.4 LTS, x86_64, 3.2.0-60-generic $ cat /etc/sysctl.conf net.ipv4.conf.eth0.arp_notify = 1 vm.swappiness = 0 net.ipv4.tcp_rmem = 4096 87380 4194304 net.ipv4.tcp_wmem = 4096 16384 4194304 net.core.wmem_default = 8388608 net.core.rmem_default = 8388608 net.core.rmem_max = 16777216 net.core.wmem_max = 16777216

问题 I'm trying to understand and use the kernel hash tables and I've already read this and this link, but I didn't understand none of them. My first question is: Why our struct has to have the struct h_list inside it? If we're gonna access our struct through the struct h_list our struct shouldn't be within struct h_list and not the opposite? After reading the tutorial I've tried to write the following code: DECLARE_HASHTABLE(nodes_hash, 3) hash_init(nodes_hash); struct h_node{ int data; char name

问题 I am trying to understand how the Linux GPIO numbers get their values. e.g. GPIO mapping for Joule. I tried reading linux documentation on Pinctrl Subsystem and also looked at the code of GPIO driver being used in Intel Joule : https://elixir.bootlin.com/linux/latest/source/drivers/pinctrl/intel/pinctrl-broxton.c However going this way looks very platform-specific. I am looking for some generic industry standard. Please help or please direct me to some good article. 回答1: First of all, one has

问题 I am trying to understand how the Linux GPIO numbers get their values. e.g. GPIO mapping for Joule. I tried reading linux documentation on Pinctrl Subsystem and also looked at the code of GPIO driver being used in Intel Joule : https://elixir.bootlin.com/linux/latest/source/drivers/pinctrl/intel/pinctrl-broxton.c However going this way looks very platform-specific. I am looking for some generic industry standard. Please help or please direct me to some good article. 回答1: First of all, one has

问题 I was trying to understand how current macro works, so started browsing the Linux Kernel source code version 4.19. Was trying to understand for x86 architecture include/asm-generic/current.h:8 #define get_current() (current_thread_info()->task) #define current get_current() I then tried to find the definition of current_thread_info(). include/linux/thread_info.h #ifdef CONFIG_THREAD_INFO_IN_TASK /* * For CONFIG_THREAD_INFO_IN_TASK kernels we need <asm/current.h> for the * definition of

问题 I was trying to understand how current macro works, so started browsing the Linux Kernel source code version 4.19. Was trying to understand for x86 architecture include/asm-generic/current.h:8 #define get_current() (current_thread_info()->task) #define current get_current() I then tried to find the definition of current_thread_info(). include/linux/thread_info.h #ifdef CONFIG_THREAD_INFO_IN_TASK /* * For CONFIG_THREAD_INFO_IN_TASK kernels we need <asm/current.h> for the * definition of

问题 I am using SAMA5D27-SOM1-EK1 Microchip embedded board. I am using Linux kernel 4.14.73 version that I build using Yocto project. That board has a J27 connector that is used as Image Sensor Interface as shown in 4.3.2 Title, page 31 from the board user guide document, besides, Table 4-16. ISC Connector J27 Pin Assignment, page 32 , shows the connector PIN features. This is a link to the board document : SAMA5D27_User_guide My goal is to change some PIN features of this connector, in order to

问题 I am using SAMA5D27-SOM1-EK1 Microchip embedded board. I am using Linux kernel 4.14.73 version that I build using Yocto project. That board has a J27 connector that is used as Image Sensor Interface as shown in 4.3.2 Title, page 31 from the board user guide document, besides, Table 4-16. ISC Connector J27 Pin Assignment, page 32 , shows the connector PIN features. This is a link to the board document : SAMA5D27_User_guide My goal is to change some PIN features of this connector, in order to