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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
#include <vmlinux.h>
#include <bpf/bpf_tracing.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
#include "bpf_experimental.h"
#include "bpf_arena_common.h"
struct arr_elem {
struct bpf_res_spin_lock lock;
};
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, int);
__type(value, struct arr_elem);
} arrmap SEC(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARENA);
__uint(map_flags, BPF_F_MMAPABLE);
__uint(max_entries, 1); /* number of pages */
} arena SEC(".maps");
struct elem {
struct bpf_timer timer;
};
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(max_entries, 1);
__type(key, int);
__type(value, struct elem);
} array SEC(".maps");
#define ENOSPC 28
#define _STR "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
int size;
u64 fault_addr;
void *arena_ptr;
SEC("syscall")
__success __retval(0)
int stream_exhaust(void *ctx)
{
/* Use global variable for loop convergence. */
size = 0;
bpf_repeat(BPF_MAX_LOOPS) {
if (bpf_stream_printk(BPF_STDOUT, _STR) == -ENOSPC && size == 99954)
return 0;
size += sizeof(_STR) - 1;
}
return 1;
}
SEC("syscall")
__arch_x86_64
__arch_arm64
__arch_s390x
__success __retval(0)
__stderr("ERROR: Timeout detected for may_goto instruction")
__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
__stderr("Call trace:\n"
"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
"|[ \t]+[^\n]+\n)*}}")
int stream_cond_break(void *ctx)
{
while (can_loop)
;
return 0;
}
SEC("syscall")
__success __retval(0)
__stderr("ERROR: AA or ABBA deadlock detected for bpf_res_spin_lock")
__stderr("{{Attempted lock = (0x[0-9a-fA-F]+)\n"
"Total held locks = 1\n"
"Held lock\\[ 0\\] = \\1}}")
__stderr("...")
__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
__stderr("Call trace:\n"
"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
"|[ \t]+[^\n]+\n)*}}")
int stream_deadlock(void *ctx)
{
struct bpf_res_spin_lock *lock, *nlock;
lock = bpf_map_lookup_elem(&arrmap, &(int){0});
if (!lock)
return 1;
nlock = bpf_map_lookup_elem(&arrmap, &(int){0});
if (!nlock)
return 1;
if (bpf_res_spin_lock(lock))
return 1;
if (bpf_res_spin_lock(nlock)) {
bpf_res_spin_unlock(lock);
return 0;
}
bpf_res_spin_unlock(nlock);
bpf_res_spin_unlock(lock);
return 1;
}
SEC("syscall")
__success __retval(0)
int stream_syscall(void *ctx)
{
bpf_stream_printk(BPF_STDOUT, "foo");
return 0;
}
SEC("syscall")
__arch_x86_64
__arch_arm64
__success __retval(0)
__stderr("ERROR: Arena WRITE access at unmapped address 0x{{.*}}")
__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
__stderr("Call trace:\n"
"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
"|[ \t]+[^\n]+\n)*}}")
int stream_arena_write_fault(void *ctx)
{
struct bpf_arena *ptr = (void *)&arena;
u64 user_vm_start;
/* Prevent GCC bounds warning: casting &arena to struct bpf_arena *
* triggers bounds checking since the map definition is smaller than struct
* bpf_arena. barrier_var() makes the pointer opaque to GCC, preventing the
* bounds analysis
*/
barrier_var(ptr);
user_vm_start = ptr->user_vm_start;
fault_addr = user_vm_start + 0x7fff;
bpf_addr_space_cast(user_vm_start, 0, 1);
asm volatile (
"r1 = %0;"
"r2 = 1;"
"*(u32 *)(r1 + 0x7fff) = r2;"
:
: "r" (user_vm_start)
: "r1", "r2"
);
return 0;
}
SEC("syscall")
__arch_x86_64
__arch_arm64
__success __retval(0)
__stderr("ERROR: Arena READ access at unmapped address 0x{{.*}}")
__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
__stderr("Call trace:\n"
"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
"|[ \t]+[^\n]+\n)*}}")
int stream_arena_read_fault(void *ctx)
{
struct bpf_arena *ptr = (void *)&arena;
u64 user_vm_start;
/* Prevent GCC bounds warning: casting &arena to struct bpf_arena *
* triggers bounds checking since the map definition is smaller than struct
* bpf_arena. barrier_var() makes the pointer opaque to GCC, preventing the
* bounds analysis
*/
barrier_var(ptr);
user_vm_start = ptr->user_vm_start;
fault_addr = user_vm_start + 0x7fff;
bpf_addr_space_cast(user_vm_start, 0, 1);
asm volatile (
"r1 = %0;"
"r1 = *(u32 *)(r1 + 0x7fff);"
:
: "r" (user_vm_start)
: "r1"
);
return 0;
}
static __noinline void subprog(void)
{
int __arena *addr = (int __arena *)0xdeadbeef;
arena_ptr = &arena;
*addr = 1;
}
SEC("syscall")
__arch_x86_64
__arch_arm64
__success __retval(0)
__stderr("ERROR: Arena WRITE access at unmapped address 0x{{.*}}")
__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
__stderr("Call trace:\n"
"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
"|[ \t]+[^\n]+\n)*}}")
int stream_arena_subprog_fault(void *ctx)
{
subprog();
return 0;
}
static __noinline int timer_cb(void *map, int *key, struct bpf_timer *timer)
{
int __arena *addr = (int __arena *)0xdeadbeef;
arena_ptr = &arena;
*addr = 1;
return 0;
}
SEC("syscall")
__arch_x86_64
__arch_arm64
__success __retval(0)
__stderr("ERROR: Arena WRITE access at unmapped address 0x{{.*}}")
__stderr("CPU: {{[0-9]+}} UID: 0 PID: {{[0-9]+}} Comm: {{.*}}")
__stderr("Call trace:\n"
"{{([a-zA-Z_][a-zA-Z0-9_]*\\+0x[0-9a-fA-F]+/0x[0-9a-fA-F]+\n"
"|[ \t]+[^\n]+\n)*}}")
int stream_arena_callback_fault(void *ctx)
{
struct bpf_timer *arr_timer;
arr_timer = bpf_map_lookup_elem(&array, &(int){0});
if (!arr_timer)
return 0;
bpf_timer_init(arr_timer, &array, 1);
bpf_timer_set_callback(arr_timer, timer_cb);
bpf_timer_start(arr_timer, 0, 0);
return 0;
}
char _license[] SEC("license") = "GPL";
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