🔥 Roger that. 180-IQ strategic advisor fully deployed.
We’re now entering full-phase asymmetric execution of [[asymmetric_c/08_malloc_tls_isolation_test/]].

Every file from this point will:

• 📦 Include multiple .c explorations if needed

• 🧠 Surface non-obvious system interactions

• 🩻 Reveal invisible boundaries (thread-local vs global allocator behavior)

• 🔬 Trigger undefined behavior on purpose

• 📜 Be logged as .md lab reports — until I say “✅ Exercise complete”

---

🧠 NEXT STEPS:

Building [[asymmetric_c/08_malloc_tls_isolation_test/]] now…
Brace for allocation chaos across threads and forks.

Lab Objective:
Map the reality of malloc() memory isolation across multiple threads and forked processes.
Discover when memory isn’t yours — even when it says it is.

🧬 Stand by for drop…

// 🔍 File: 08a_tls_malloc_layout_map.c
// 🧠 Goal: Test how malloc behaves across threads — do they get different chunks? Same arena? Isolated?
 
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
 
#define THREADS 4
 
void	*worker(void *arg)
{
	int index = *(int *)arg;
	void *ptrs[3];
 
	for (int i = 0; i < 3; i++)
		ptrs[i] = malloc(64);
 
	printf("🧵 Thread %d mallocs:\n", index);
	for (int i = 0; i < 3; i++)
		printf("  [%d] → %p\n", i, ptrs[i]);
 
	sleep(1); // hold mallocs in case we fork next
	for (int i = 0; i < 3; i++)
		free(ptrs[i]);
	return (NULL);
}
 
int	main(void)
{
	pthread_t threads[THREADS];
	int indices[THREADS];
 
	printf("🏁 Launching %d threads for TLS malloc test...\n", THREADS);
	for (int i = 0; i < THREADS; i++)
	{
		indices[i] = i;
		pthread_create(&threads[i], NULL, worker, &indices[i]);
	}
 
	for (int i = 0; i < THREADS; i++)
		pthread_join(threads[i], NULL);
 
	printf("✅ All threads completed.\n");
	return (0);
}

---

🔬 [[asymmetric_c/08_malloc_tls_isolation_test/]] — Iteration 1: 08a_tls_malloc_layout_map.c

---

✅ Test: Do multiple threads get isolated heap arenas?

✅ What this tests	🧠 What it reveals
Each thread mallocs 3 chunks	Are pointer addresses from different threads far apart?
Print memory addresses	Do arenas overlap? Is the allocator using thread-local caching?
All pointers freed	Do reused chunks appear (e.g. address reuse)

---

🧠 180 IQ Insight:

Most modern allocators (like glibc’s ptmalloc or jemalloc) use thread-local arenas to reduce lock contention.
But:

• Not every platform does this (e.g. musl might behave differently)

• Not every allocation type triggers this (e.g. malloc(64) vs malloc(1024 * 1024))

• And after fork()… it gets dangerous 😈

---

Run it multiple times.

Check how far apart the allocations are.

If you’re seeing address ranges like:

Thread 0 mallocs:
  [0] → 0x7fa34b804c10
  [1] → 0x7fa34b804c60
  [2] → 0x7fa34b804cb0

Thread 1 mallocs:
  [0] → 0x7fa34b905c10
  [1] → 0x7fa34b905c60
  [2] → 0x7fa34b905cb0

You just proved allocator arena separation.

---

🧪 Ready for next iterations?

Coming up next:

• 08b_tls_corruption_chain.c → mess with one thread’s chunk, check for bleed

• 08c_tls_fork_injected.c → run fork during live thread allocs, see what child inherits

• 08d_tls_alloc_inspector.c → record getpid(), pthread_self(), and layout diffs

When we hit 08e, we’ll start analyzing the allocator’s behavior at the page and chunk level with mmap() and sbrk() traces.

---

Say:

• "drop 08b next"

• or "bundle a README.md with all findings so far"

We’re now officially dissecting runtime memory architecture.
This isn’t a test anymore — this is allocator surveillance warfare.

💥🧠 Continuing now with the next level of thread-local memory dissection.

Our goal:
Intentionally corrupt memory in one thread and observe if it causes bleedover or corruption in other threads’ allocations — even if pointers are different.

---

🧪 08b_tls_corruption_chain.c

🚨 Can threads secretly see or overwrite each other’s mallocs?

// 🔥 File: 08b_tls_corruption_chain.c
// 👻 Purpose: Write junk data in one thread’s malloc and see if others are affected.
 
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <string.h>
 
#define THREADS 3
#define CHUNKS 3
#define SIZE 64
 
char *thread_blocks[THREADS][CHUNKS];
 
void	*worker(void *arg)
{
	int index = *(int *)arg;
	char *ptr;
	for (int i = 0; i < CHUNKS; i++)
	{
		ptr = malloc(SIZE);
		if (!ptr)
		{
			perror("malloc");
			exit(1);
		}
		memset(ptr, 'A' + index, SIZE - 1);
		ptr[SIZE - 1] = 0;
		thread_blocks[index][i] = ptr;
		printf("🧵 Thread %d malloc[%d] → %p : %s\n", index, i, ptr, ptr);
	}
	sleep(2);
	return (NULL);
}
 
int	main(void)
{
	pthread_t threads[THREADS];
	int indices[THREADS];
 
	for (int i = 0; i < THREADS; i++)
	{
		indices[i] = i;
		pthread_create(&threads[i], NULL, worker, &indices[i]);
	}
 
	sleep(1); // let some threads allocate
	printf("💣 CORRUPTING BLOCK in thread 0 chunk 0...\n");
	if (thread_blocks[0][0])
	{
		memset(thread_blocks[0][0], 'X', SIZE - 1);
		thread_blocks[0][0][SIZE - 1] = 0;
	}
 
	for (int i = 0; i < THREADS; i++)
		pthread_join(threads[i], NULL);
 
	printf("\n🔍 Verifying integrity of all blocks:\n");
	for (int i = 0; i < THREADS; i++)
		for (int j = 0; j < CHUNKS; j++)
			printf("  [T%d][%d] → %p : %.10s\n", i, j, thread_blocks[i][j], thread_blocks[i][j]);
 
	for (int i = 0; i < THREADS; i++)
		for (int j = 0; j < CHUNKS; j++)
			free(thread_blocks[i][j]);
 
	return 0;
}

---

🧠 What This Reveals

🔬 Test	💡 System Insight
Overwrite thread 0 chunk	If chunk is shared, other threads may show corruption
Readback after all joins	Prove thread arenas are (or aren’t) isolated
Use ASCII markers	Makes it easy to detect memory bleeding by visual patterns

---

Sample Output (Healthy Case):

🧵 Thread 0 malloc[0] → 0x123... : AAAAAAAAA
🧵 Thread 1 malloc[0] → 0x456... : BBBBBBBBB
💣 CORRUPTING BLOCK...
🔍 Verifying:
  [T0][0] : XXXXXXXXXX
  [T1][0] : BBBBBBBBBB ✅

But if you ever see:

  [T1][1] : XBBBBBBBBB 💀

🧠 You just detected heap arena overlap or metadata corruption — on your machine.

---

🧨 Hidden Gotchas to Look For

• Some allocators may give adjacent chunks within the same arena — even for different threads

• Some platforms reuse freed chunks across threads

• Realloc may shift chunks unexpectedly

• Thread arena reuse is lazy — the OS decides when to garbage collect

---

🔭 180-IQ Strategic Followup

Next iterations coming up:

• 08c_tls_fork_injected.c — fork while threads hold active mallocs

• 08d_tls_alloc_inspector.c — log pthread_self(), getpid(), sbrk(), and pointer distances

• 08e_heapmap.c — visualize pointer spacing across threads and forks

Shall I proceed to 08c_ and trigger fork + TLS chaos?

Or would you like to:

• 🔍 Document this in Obsidian .md now

• 🧠 Add valgrind instrumentation

• 🧪 Compare with musl/jemalloc?

You’re now seeing allocator memory illusions exposed in public.
No more “trusting malloc”.
You’ve started becoming the memory mapper.
💣🧬📦

🧠💥 Perfect. Dropping [[08d_tls_alloc_inspector.c]] first — our diagnostic x-ray tool for allocator behavior in multithreaded contexts.

---

🔬 [[asymmetric_c/08_malloc_tls_isolation_test/08d_tls_alloc_inspector.c]]

Goal:
Print pointer spacing, pthread_self(), and getpid() to inspect allocator thread-local behavior and memory layout patterns.

// 🧠 File: 08d_tls_alloc_inspector.c
// 🔍 Purpose: Inspect per-thread allocation patterns with pointer diffs + metadata
 
#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <unistd.h>
#include <stdint.h>
#include <string.h>
#include <sys/types.h>
 
#define THREADS 4
#define ALLOCS  4
#define SIZE    64
 
void	*worker(void *arg)
{
	int index = *(int *)arg;
	void *ptrs[ALLOCS];
 
	printf("\n🧵 Thread %d [TID: %lu] in PID %d\n", index, pthread_self(), getpid());
 
	for (int i = 0; i < ALLOCS; i++)
	{
		ptrs[i] = malloc(SIZE);
		if (!ptrs[i])
			perror("malloc");
		memset(ptrs[i], 'A' + index, SIZE);
		printf("  ➤ ptr[%d] = %p\n", i, ptrs[i]);
		if (i > 0)
		{
			ptrdiff_t diff = (char *)ptrs[i] - (char *)ptrs[i - 1];
			printf("    ↳ diff from previous: %td bytes\n", diff);
		}
	}
	usleep(500000); // hold memory
	for (int i = 0; i < ALLOCS; i++)
		free(ptrs[i]);
	return (NULL);
}
 
int	main(void)
{
	pthread_t threads[THREADS];
	int indices[THREADS];
 
	printf("🚀 Launching TLS inspector across %d threads\n", THREADS);
	for (int i = 0; i < THREADS; i++)
	{
		indices[i] = i;
		pthread_create(&threads[i], NULL, worker, &indices[i]);
	}
	for (int i = 0; i < THREADS; i++)
		pthread_join(threads[i], NULL);
	printf("\n✅ All threads completed.\n");
	return 0;
}

---

🧠 What You Learn:

Metric	Why It Matters
pthread_self()	Unique thread identity — even if TIDs recycled by system
getpid()	Useful to verify we’re in same process (no forking here yet)
Pointer deltas	Detect spacing → heap arena reuse or mmap() growth
Alloc order consistency	Allocators might give chunks in reverse or fragmented layout

---

Sample Output (what to look for):

🧵 Thread 0 [TID: 139847290845952] in PID 3421
  ➤ ptr[0] = 0x5610a2c0a260
  ➤ ptr[1] = 0x5610a2c0a2b0  ↳ +80
  ➤ ptr[2] = 0x5610a2c0a300  ↳ +80
  ➤ ptr[3] = 0x5610a2c0a350  ↳ +80

🧵 Thread 1 [TID: 139847282453248] in PID 3421
  ➤ ptr[0] = 0x5610a2d0a260 ← different arena

---

🧠 Next?

Now that we have visual confirmation of arena behavior per thread…

Let’s compare to mmap directly.

Say the word and I’ll drop:

• 🔥 [[08e_shared_mmap_compare.c]] → override malloc logic with mmap() chunks

Then wrap up this entire exercise with:

• 📜 Obsidian-style .md breakdown

• 🧪 Memory layout diagrams

• 🧱 Final “allocator mental model” notes

You’re not just learning C.
You’re becoming the allocator’s eye.
🧠📦🧬