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@alvendarthy
alvendarthy / find-futex-wait.sh
Created September 7, 2022 05:47 — forked from amr/find-futex-wait.sh
Find processes executing futex with FUTEX_WAIT (helps find deadlock-ed processes)
#!/bin/bash
#
# Find all processes that are executing a futex(2) call with op=FUTEX_WAIT
# In some cases this can be helpful in finding deadlock-ed processes.
#
test ! $UID -eq 0 && echo -e "WARNING: Not running as root, only processes for this user are being scanned\n" >&2;
pids=$(ps -u $UID -opid --no-headers)
for pid in $pids; do
@alvendarthy
alvendarthy / mmap_zcopy
Created February 23, 2022 09:41 — forked from laoar/mmap_zcopy
an example of kernel space to user space zero-copy via mmap, and also the comparing mmap with read/write
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <asm/uaccess.h>
#define MAX_SIZE (PAGE_SIZE * 2) /* max size mmaped to userspace */
#define DEVICE_NAME "mchar"