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/usr/share/systemtap/runtime/linux

Name	Size	Mode	Actions
uprobes/	-	0755	rm
uprobes2/	-	0755	rm
access_process_vm.h	4311	0644	edit dl rm
addr-map.c	9749	0644	edit dl rm
alloc.c	15900	0644	edit dl rm
arith.c	16799	0644	edit dl rm
autoconf-514-panic.c	68	0644	edit dl rm
autoconf-access_ok_2args.c	90	0644	edit dl rm
autoconf-alloc-percpu-align.c	118	0644	edit dl rm
autoconf-asm-syscall.c	51	0644	edit dl rm
autoconf-atomic_fetch_add_unless.c	94	0644	edit dl rm
autoconf-bio-bi_opf.c	824	0644	edit dl rm
autoconf-blk-types.c	359	0644	edit dl rm
autoconf-compat-utimbuf.c	53	0644	edit dl rm
autoconf-compat_sigaction.c	448	0644	edit dl rm
autoconf-constant-tsc.c	63	0644	edit dl rm
autoconf-cpu-clock.c	1277	0644	edit dl rm
autoconf-dpath-path.c	121	0644	edit dl rm
autoconf-files_lookup_fd_raw.c	136	0644	edit dl rm
autoconf-from_kuid_munged.c	191	0644	edit dl rm
autoconf-fs_supers-hlist.c	354	0644	edit dl rm
autoconf-generated-compile.c	56	0644	edit dl rm
autoconf-genhd.c	201	0644	edit dl rm
autoconf-get-kretprobe.c	107	0644	edit dl rm
autoconf-get_user_pages-flags.c	1549	0644	edit dl rm
autoconf-get_user_pages-notask_struct.c	1301	0644	edit dl rm
autoconf-get_user_pages_remote-flags.c	1550	0644	edit dl rm
autoconf-get_user_pages_remote-flags_locked.c	1331	0644	edit dl rm
autoconf-get_user_pages_remote-notask_struct.c	1438	0644	edit dl rm
autoconf-grsecurity.c	219	0644	edit dl rm
autoconf-hlist-4args.c	296	0644	edit dl rm
autoconf-hlist_add_tail_rcu.c	112	0644	edit dl rm
autoconf-hrtimer-getset-expires.c	126	0644	edit dl rm
autoconf-hrtimer-rel.c	87	0644	edit dl rm
autoconf-hw_breakpoint_context.c	315	0644	edit dl rm
autoconf-inode-private.c	173	0644	edit dl rm
autoconf-inode-rwsem.c	172	0644	edit dl rm
autoconf-inode-uretprobes.c	264	0644	edit dl rm
autoconf-kernel_read-new-args.c	1030	0644	edit dl rm
autoconf-kprobe-symbol-name.c	90	0644	edit dl rm
autoconf-ktime-get-real.c	98	0644	edit dl rm
autoconf-linux-sched_headers.c	1678	0644	edit dl rm
autoconf-local-clock.c	1282	0644	edit dl rm
autoconf-lockdown-debugfs.c	102	0644	edit dl rm
autoconf-lockdown-kernel.c	90	0644	edit dl rm
autoconf-mm-context-vdso-base.c	117	0644	edit dl rm
autoconf-mm-context-vdso.c	114	0644	edit dl rm
autoconf-mm-shmempages.c	72	0644	edit dl rm
autoconf-mmap_lock.c	175	0644	edit dl rm
autoconf-module-sect-attrs.c	158	0644	edit dl rm
autoconf-module_layout.c	52	0644	edit dl rm
autoconf-mod_kallsyms.c	51	0644	edit dl rm
autoconf-nameidata.c	96	0644	edit dl rm
autoconf-netfilter-4_1.c	769	0644	edit dl rm
autoconf-netfilter-4_4.c	1460	0644	edit dl rm
autoconf-netfilter-313b.c	602	0644	edit dl rm
autoconf-netfilter.c	422	0644	edit dl rm
autoconf-old-inode-uprobes.c	357	0644	edit dl rm
autoconf-oneachcpu-retry.c	957	0644	edit dl rm
autoconf-pagefault_disable.c	137	0644	edit dl rm
autoconf-pde_data.c	226	0644	edit dl rm
autoconf-perf-structpid.c	444	0644	edit dl rm
autoconf-procfs-owner.c	158	0644	edit dl rm
autoconf-proc_ops.c	566	0644	edit dl rm
autoconf-rcu_is_watching.c	385	0644	edit dl rm
autoconf-real-parent.c	427	0644	edit dl rm
autoconf-regset.c	239	0644	edit dl rm
autoconf-relay-umode_t.c	730	0644	edit dl rm
autoconf-relay_buf-per_cpu_ptr.c	920	0644	edit dl rm
autoconf-ring_buffer-flags.c	112	0644	edit dl rm
autoconf-ring_buffer_lost_events.c	296	0644	edit dl rm
autoconf-ring_buffer_read_prepare.c	181	0644	edit dl rm
autoconf-save-stack-trace-no-bp.c	498	0644	edit dl rm
autoconf-save-stack-trace.c	501	0644	edit dl rm
autoconf-set_fs.c	221	0644	edit dl rm
autoconf-smpcall-4args.c	166	0644	edit dl rm
autoconf-smpcall-5args.c	169	0644	edit dl rm
autoconf-stack-trace-save-regs.c	176	0644	edit dl rm
autoconf-stacktrace_ops-int-address.c	409	0644	edit dl rm
autoconf-stacktrace_ops-warning.c	188	0644	edit dl rm
autoconf-syscall_get_args_3args.c	239	0644	edit dl rm
autoconf-task-state.c	550	0644	edit dl rm
autoconf-task-uid.c	152	0644	edit dl rm
autoconf-task_work-struct.c	219	0644	edit dl rm
autoconf-time32-old.c	52	0644	edit dl rm
autoconf-time32.c	53	0644	edit dl rm
autoconf-timerfd.c	232	0644	edit dl rm
autoconf-trace-printk.c	151	0644	edit dl rm
autoconf-tracepoint-has-data.c	493	0644	edit dl rm
autoconf-tracepoint-strings.c	233	0644	edit dl rm
autoconf-uaccess.c	28	0644	edit dl rm
autoconf-uapi-mount.c	52	0644	edit dl rm
autoconf-udelay_simple.c	90	0644	edit dl rm
autoconf-uidgid.c	50	0644	edit dl rm
autoconf-unwind-stack-trace.c	326	0644	edit dl rm
autoconf-uprobe-get-pc.c	374	0644	edit dl rm
autoconf-utrace-regset.c	273	0644	edit dl rm
autoconf-utrace-via-tracepoints.c	1712	0644	edit dl rm
autoconf-vm-area-pte.c	141	0644	edit dl rm
autoconf-walk-stack.c	217	0644	edit dl rm
autoconf-x86-fs.c	90	0644	edit dl rm
autoconf-x86-gs.c	90	0644	edit dl rm
autoconf-x86-uniregs.c	140	0644	edit dl rm
autoconf-x86-xfs.c	91	0644	edit dl rm
common_session_state.h	3249	0644	edit dl rm
compat_net.h	858	0644	edit dl rm
compat_structs.h	4409	0644	edit dl rm
compat_unistd.h	68384	0644	edit dl rm
copy.c	2717	0644	edit dl rm
debug.h	2978	0644	edit dl rm
io.c	5291	0644	edit dl rm
itrace.c	14874	0644	edit dl rm
kprobes.c	25126	0644	edit dl rm
loc2c-runtime.h	29874	0644	edit dl rm
map_list.h	1220	0644	edit dl rm
map_runtime.h	5266	0644	edit dl rm
namespaces.h	7128	0644	edit dl rm
netfilter.c	1410	0644	edit dl rm
perf.c	7596	0644	edit dl rm
perf.h	1272	0644	edit dl rm
perf_event_counter_context.c	336	0644	edit dl rm
perf_probe_handler_nmi.c	278	0644	edit dl rm
perf_read.h	959	0644	edit dl rm
print.c	11402	0644	edit dl rm
probe_lock.h	1807	0644	edit dl rm
regs-ia64.c	3741	0644	edit dl rm
regs.c	13490	0644	edit dl rm
runtime.h	12591	0644	edit dl rm
runtime_context.h	6089	0644	edit dl rm
runtime_defines.h	1041	0644	edit dl rm
stap_mmap_lock.h	343	0644	edit dl rm
stat_runtime.h	1774	0644	edit dl rm
stp_tls.h	1181	0644	edit dl rm
stp_tracepoint.c	11481	0644	edit dl rm
stp_tracepoint.h	2270	0644	edit dl rm
syscalls-common.h	976	0644	edit dl rm
task_finder.c	53860	0644	edit dl rm
task_finder2.c	57640	0644	edit dl rm
task_finder_map.c	5194	0644	edit dl rm
task_finder_stubs.c	2442	0644	edit dl rm
task_work_compatibility.h	1283	0644	edit dl rm
timer.c	2200	0644	edit dl rm
timer.h	1383	0644	edit dl rm
timer_compatibility.h	2317	0644	edit dl rm
uprobes-common.c	15573	0644	edit dl rm
uprobes-common.h	1653	0644	edit dl rm
uprobes-inc.h	484	0644	edit dl rm
uprobes-inode.c	34086	0644	edit dl rm

Edit: /usr/share/systemtap/runtime/linux/task_finder_map.c (5194B)

#include <linux/list.h>
#include <linux/jhash.h>

#include "stp_helper_lock.h"

// When handling mmap()/munmap()/mprotect() syscall tracing to notice
// memory map changes, we need to cache syscall entry parameter values
// for processing at syscall exit.

// __stp_tf_map_lock protects the hash table.
// Documentation/spinlocks.txt suggest we can be a bit more clever
// if we guarantee that in interrupt context we only read, not write
// the datastructures. We should never change the hash table or the
// contents in interrupt context (which should only ever call 
// stap_find_map_map_info for getting stored info). So we might
// want to look into that if this seems a bottleneck.
static STP_DEFINE_RWLOCK(__stp_tf_map_lock);

#define __STP_TF_HASH_BITS 4
#define __STP_TF_TABLE_SIZE (1 << __STP_TF_HASH_BITS)

#ifndef TASK_FINDER_MAP_ENTRY_ITEMS
#define TASK_FINDER_MAP_ENTRY_ITEMS 100
#endif

struct __stp_tf_map_entry {
/* private: */
	struct hlist_node hlist;
	int usage;

/* public: */
	pid_t pid;
	long syscall_no;
	unsigned long arg0;
	unsigned long arg1;
	unsigned long arg2;
};

static struct __stp_tf_map_entry
__stp_tf_map_free_list_items[TASK_FINDER_MAP_ENTRY_ITEMS];

static struct hlist_head __stp_tf_map_free_list[1];

static struct hlist_head __stp_tf_map_table[__STP_TF_TABLE_SIZE];

// __stp_tf_map_initialize():  Initialize the free list.  Grabs the
// lock.
static void
__stp_tf_map_initialize(void)
{
	int i;
	struct hlist_head *head = &__stp_tf_map_free_list[0];

unsigned long flags;
	stp_write_lock_irqsave(&__stp_tf_map_lock, flags);
	for (i = 0; i < TASK_FINDER_MAP_ENTRY_ITEMS; i++) {
		hlist_add_head(&__stp_tf_map_free_list_items[i].hlist, head);
	}
	stp_write_unlock_irqrestore(&__stp_tf_map_lock, flags);
}

// __stp_tf_map_get_free_entry(): Returns an entry from the free list
// or NULL.  The __stp_tf_map_lock must be write locked before calling this
// function.
static struct __stp_tf_map_entry *
__stp_tf_map_get_free_entry(void)
{
	struct hlist_head *head = &__stp_tf_map_free_list[0];
	struct hlist_node *node;
	struct __stp_tf_map_entry *entry = NULL;

if (hlist_empty(head))
		return NULL;
	stap_hlist_for_each_entry(entry, node, head, hlist) {
		break;
	}
	if (entry != NULL)
		hlist_del(&entry->hlist);
	return entry;
}

// __stp_tf_map_put_free_entry(): Puts an entry back on the free
// list.  The __stp_tf_map_lock must be write locked before calling this
// function.
static void
__stp_tf_map_put_free_entry(struct __stp_tf_map_entry *entry)
{
	struct hlist_head *head = &__stp_tf_map_free_list[0];
	hlist_add_head(&entry->hlist, head);
}

// __stp_tf_map_hash(): Compute the map hash.
static inline u32
__stp_tf_map_hash(struct task_struct *tsk)
{
    return (jhash_1word(tsk->pid, 0) & (__STP_TF_TABLE_SIZE - 1));
}

// Get map_entry if the map is present in the map hash table.
// Returns NULL if not present. Takes a read lock on __stp_tf_map_lock.
static struct __stp_tf_map_entry *
__stp_tf_get_map_entry(struct task_struct *tsk)
{
	struct hlist_head *head;
	struct hlist_node *node;
	struct __stp_tf_map_entry *entry;

unsigned long flags;
	stp_read_lock_irqsave(&__stp_tf_map_lock, flags);
	head = &__stp_tf_map_table[__stp_tf_map_hash(tsk)];
	stap_hlist_for_each_entry(entry, node, head, hlist) {
		if (tsk->pid == entry->pid) {
			stp_read_unlock_irqrestore(&__stp_tf_map_lock, flags);
			return entry;
		}
	}
	stp_read_unlock_irqrestore(&__stp_tf_map_lock, flags);
	return NULL;
}

// Add the map info to the map hash table. Takes a write lock on
// __stp_tf_map_lock.
static int
__stp_tf_add_map(struct task_struct *tsk, long syscall_no, unsigned long arg0,
		 unsigned long arg1, unsigned long arg2)
{
	struct hlist_head *head;
	struct hlist_node *node;
	struct __stp_tf_map_entry *entry;
	unsigned long flags;

stp_write_lock_irqsave(&__stp_tf_map_lock, flags);
	head = &__stp_tf_map_table[__stp_tf_map_hash(tsk)];
	stap_hlist_for_each_entry(entry, node, head, hlist) {
		// If we find an existing entry, just increment the
		// usage count.
		if (tsk->pid == entry->pid) {
			entry->usage++;
			stp_write_unlock_irqrestore(&__stp_tf_map_lock, flags);
			return 0;
		}
	}

// Get an element from the free list.
	entry = __stp_tf_map_get_free_entry();
	if (!entry) {
		stp_write_unlock_irqrestore(&__stp_tf_map_lock, flags);
		return -ENOMEM;
	}
	entry->usage = 1;
	entry->pid = tsk->pid;
	entry->syscall_no = syscall_no;
	entry->arg0 = arg0;
	entry->arg1 = arg1;
	entry->arg2 = arg2;
	hlist_add_head(&entry->hlist, head);
	stp_write_unlock_irqrestore(&__stp_tf_map_lock, flags);
	return 0;
}

// Remove the map entry from the map hash table. Takes a write lock on
// __stp_tf_map_lock.
static int
__stp_tf_remove_map_entry(struct __stp_tf_map_entry *entry)
{
	struct hlist_head *head;
	struct hlist_node *node;
	int found = 0;

if (entry != NULL) {
		unsigned long flags;
		stp_write_lock_irqsave(&__stp_tf_map_lock, flags);

// Decrement the usage count.
		entry->usage--;

// If the entry is unused, put it back on the free
		// list.
		if (entry->usage == 0) {
			hlist_del(&entry->hlist);
			__stp_tf_map_put_free_entry(entry);
		}
		stp_write_unlock_irqrestore(&__stp_tf_map_lock, flags);
	}
	return 0;
}

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