kernel/trace/trace_pid.c

File Facts

System

Linux kernel

Corpus path

kernel/trace/trace_pid.c

Extension

.c

Size

6083 bytes

Lines

247

Domain

Core OS

Bucket

Scheduler, Processes, Timers, Sync, And Syscalls

Inferred role

Core OS: implementation source

Status

source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

• Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.
• Touches user memory; correctness depends on fault-safe copying and privilege boundary handling.
• Defines or uses C structs; map object ownership, embedded links, reference counts, and lock ownership.

Dependency Surface

• trace.h

Detected Declarations

• function trace_find_filtered_pid
• function trace_ignore_this_task
• function trace_filter_add_remove_task
• function trace_pid_show
• function trace_pid_write

Annotated Snippet

while (!ret) {
			ret = trace_pid_list_set(pid_list, pid);
			if (ret < 0)
				goto out;

			ret = trace_pid_list_next(filtered_pids, pid + 1, &pid);
			nr_pids++;
		}
	}

	ret = 0;
	while (cnt > 0) {

		pos = 0;

		ret = trace_get_user(&parser, ubuf, cnt, &pos);
		if (ret < 0)
			break;

		read += ret;
		ubuf += ret;
		cnt -= ret;

		if (!trace_parser_loaded(&parser))
			break;

		ret = -EINVAL;
		if (kstrtoul(parser.buffer, 0, &val))
			break;

		pid = (pid_t)val;

		if (trace_pid_list_set(pid_list, pid) < 0) {
			ret = -1;
			break;
		}
		nr_pids++;

		trace_parser_clear(&parser);
		ret = 0;
	}
 out:
	trace_parser_put(&parser);

	if (ret < 0) {
		trace_pid_list_free(pid_list);
		return ret;
	}

	if (!nr_pids) {
		/* Cleared the list of pids */
		trace_pid_list_free(pid_list);
		pid_list = NULL;
	}

	*new_pid_list = pid_list;

	return read;
}

Annotation

• Immediate include surface: `trace.h`.
• Detected declarations: `function trace_find_filtered_pid`, `function trace_ignore_this_task`, `function trace_filter_add_remove_task`, `function trace_pid_show`, `function trace_pid_write`.
• Atlas domain: Core OS / Scheduler, Processes, Timers, Sync, And Syscalls.
• Implementation status: source implementation candidate.
• This snippet crosses the user/kernel memory boundary; validate fault handling and access checks before translating the pattern.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.