Commit 4460fdad authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Ingo Molnar
Browse files

tracing, Text Edit Lock - kprobes architecture independent support 



Use the mutual exclusion provided by the text edit lock in the kprobes code. It
allows coherent manipulation of the kernel code by other subsystems.

Changelog:

Move the kernel_text_lock/unlock out of the for loops.
Use text_mutex directly instead of a function.
Remove whitespace modifications.

(note : kprobes_mutex is always taken outside of text_mutex)

Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Acked-by: default avatarAnanth N Mavinakayanahalli <ananth@in.ibm.com>
Acked-by: default avatarMasami Hiramatsu <mhiramat@redhat.com>
LKML-Reference: <49B14306.2080202@redhat.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 0e39ac44

kernel/kprobes.c

+13 −2
Original line number Diff line number Diff line
@@ -43,6 +43,7 @@ 
#include <linux/seq_file.h>

#include <linux/debugfs.h>

#include <linux/kdebug.h>

#include <linux/memory.h>



#include <asm-generic/sections.h>

#include <asm/cacheflush.h>
@@ -699,9 +700,10 @@ int __kprobes register_kprobe(struct kprobe *p) 
		goto out;

	}



	mutex_lock(&text_mutex);

	ret = arch_prepare_kprobe(p);

	if (ret)

		goto out;

		goto out_unlock_text;



	INIT_HLIST_NODE(&p->hlist);

	hlist_add_head_rcu(&p->hlist,
@@ -710,6 +712,8 @@ int __kprobes register_kprobe(struct kprobe *p) 
	if (kprobe_enabled)

		arch_arm_kprobe(p);



out_unlock_text:

	mutex_unlock(&text_mutex);

out:

	mutex_unlock(&kprobe_mutex);
@@ -746,8 +750,11 @@ valid_p: 
		 * enabled and not gone - otherwise, the breakpoint would

		 * already have been removed. We save on flushing icache.

		 */

		if (kprobe_enabled && !kprobe_gone(old_p))

		if (kprobe_enabled && !kprobe_gone(old_p)) {

			mutex_lock(&text_mutex);

			arch_disarm_kprobe(p);

			mutex_unlock(&text_mutex);

		}

		hlist_del_rcu(&old_p->hlist);

	} else {

		if (p->break_handler && !kprobe_gone(p))
@@ -1280,12 +1287,14 @@ static void __kprobes enable_all_kprobes(void) 
	if (kprobe_enabled)

		goto already_enabled;



	mutex_lock(&text_mutex);

	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {

		head = &kprobe_table[i];

		hlist_for_each_entry_rcu(p, node, head, hlist)

			if (!kprobe_gone(p))

				arch_arm_kprobe(p);

	}

	mutex_unlock(&text_mutex);



	kprobe_enabled = true;

	printk(KERN_INFO "Kprobes globally enabled\n");
@@ -1310,6 +1319,7 @@ static void __kprobes disable_all_kprobes(void) 


	kprobe_enabled = false;

	printk(KERN_INFO "Kprobes globally disabled\n");

	mutex_lock(&text_mutex);

	for (i = 0; i < KPROBE_TABLE_SIZE; i++) {

		head = &kprobe_table[i];

		hlist_for_each_entry_rcu(p, node, head, hlist) {
@@ -1318,6 +1328,7 @@ static void __kprobes disable_all_kprobes(void) 
		}

	}



	mutex_unlock(&text_mutex);

	mutex_unlock(&kprobe_mutex);

	/* Allow all currently running kprobes to complete */

	synchronize_sched();

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