process_madvise¶

Intro¶

process_madvise - system call applied to a specific process that provides information about the process' memory layout to the kernel

Description¶

process_madvise is used to provide information about a process's memory layout to the kernel. This call is necessary for some of the more advanced memory management techniques in the kernel, such as transparent huge pages. It can also be used to advise the kernel on what kind of page replacement algorithm may be suitable for a process' memory (e.g. LRU or random).

There are some drawbacks and advantages to using process_madvise. The main advantage is that it gives the kernel more insight into the process’s memory layout, and allows for more effective memory management. The main drawback is that the process must call process_madvise for each region of memory it uses, which can slow down its execution.

Arguments¶

pidfd: int - a file descriptor for the process being analyzed.
addr: void* - address of the page within the process that is being analyzed.
length: size_t - size of the page that is being analyzed.
advice: int - advice provided to the kernel about the page.
flags: unsigned long - flags that control the behavior of the call.

Available Tags¶

K - Originated from kernel-space.
U - Originated from user space (for example, pointer to user space memory used to get it)
OPT - Optional argument - might not always be available (passed with null value)

Hooks¶

do_process_madvise¶

Type¶

Kprobes

Purpose¶

To monitor the process_madvise syscall and get information about the process being analyzed.

Example Use Case¶

The process_madvise system call could be used to provide the kernel with information about a process's memory layout when a process is initialized or when it is about to exit. This information can then be used by the kernel to make decisions about memory management, such as which page replacement algorithm to use or when to use transparent huge pages.

Issues¶

process_madvise has had some minor security issues in the past, such as the potential for kernel memory disclosure and a TOCTOU (time of check, time of use) vulnerability, but these have been addressed in recent kernel versions.

The process_madvise system call is related to other memory management system calls, such as madvise, mincore, and mprotect. It is also related to other process-specific system calls, such as process_setrlimit or process_prctl.

This document was automatically generated by OpenAI and needs review. It might not be accurate and might contain errors. The authors of Tracee recommend that the user reads the "events.go" source file to understand the events and their arguments better.