[PATCH] kprobes: no probes on critical path

For Kprobes critical path is the path from debug break exception handler till the control reaches kprobes exception code. No probes can be supported in this path as we will end up in recursion. This patch prevents this by moving the below function to safe __kprobes section onto which no probes can be inserted.

Keshavamurthy Anil S committed 20 years ago

Commit 00d7c051 parent cda315a2 files · +8 −2Browse files

Unified · Split

2 files

include/linux/kprobes.h +6 −1
kernel/sys.c +2 −1

include/linux/kprobes.h+6−1

@@ -37,6 +37,7 @@ · 36 unmodified lines
37	37	#include <linux/spinlock.h>
38	38	#include <linux/rcupdate.h>
39	39
	40	+#ifdef CONFIG_KPROBES
40	41	#include <asm/kprobes.h>
41	42
42	43	/* kprobe_status settings */
@@ -147,7 +148,6 @@ struct kretprobe_instance { · 104 unmodified lines
147	148	struct task_struct *task;
148	149	};
149	150
150		−#ifdef CONFIG_KPROBES
151	151	extern spinlock_t kretprobe_lock;
152	152	extern int arch_prepare_kprobe(struct kprobe *p);
153	153	extern void arch_copy_kprobe(struct kprobe *p);
@@ -195,6 +195,11 @@ void add_rp_inst(struct kretprobe_instance *ri); · 41 unmodified lines
195	195	void kprobe_flush_task(struct task_struct *tk);
196	196	void recycle_rp_inst(struct kretprobe_instance *ri);
197	197	#else /* CONFIG_KPROBES */
	198	+
	199	+#define __kprobes /**/
	200	+struct jprobe;
	201	+struct kretprobe;
	202	+
198	203	static inline struct kprobe *kprobe_running(void)
199	204	{
200	205	return NULL;

kernel/sys.c+2−1

@@ -32,6 +32,7 @@ · 31 unmodified lines
32	32
33	33	#include <linux/compat.h>
34	34	#include <linux/syscalls.h>
	35	+#include <linux/kprobes.h>
35	36
36	37	#include <asm/uaccess.h>
37	38	#include <asm/io.h>
@@ -168,7 +169,7 @@ EXPORT_SYMBOL(notifier_chain_unregister); · 130 unmodified lines
168	169	* of the last notifier function called.
169	170	*/
170	171
171		−int notifier_call_chain(struct notifier_block *n, unsigned long val, void v)
	172	+int __kprobes notifier_call_chain(struct notifier_block *n, unsigned long val, void v)
172	173	{
173	174	int ret=NOTIFY_DONE;
174	175	struct notifier_block nb = n;