[PATCH] Kprobes/ia64: temporary disarming of reentrant probe (852caccc) · Commits · 戴 / test

arch/ia64/kernel/kprobes.c

+43 −6

Original line number	Diff line number	Diff line
		@@ -41,8 +41,8 @@ extern void jprobe_inst_return(void);
		#define KPROBE_HIT_ACTIVE 0x00000001
		#define KPROBE_HIT_SS 0x00000002

		static struct kprobe *current_kprobe;
		static unsigned long kprobe_status;
		static struct kprobe current_kprobe, kprobe_prev;
		static unsigned long kprobe_status, kprobe_status_prev;
		static struct pt_regs jprobe_saved_regs;

		enum instruction_type {A, I, M, F, B, L, X, u};
		@@ -273,6 +273,23 @@ static int valid_kprobe_addr(int template, int slot, unsigned long addr)
		return 0;
		}

		static inline void save_previous_kprobe(void)
		{
		kprobe_prev = current_kprobe;
		kprobe_status_prev = kprobe_status;
		}

		static inline void restore_previous_kprobe(void)
		{
		current_kprobe = kprobe_prev;
		kprobe_status = kprobe_status_prev;
		}

		static inline void set_current_kprobe(struct kprobe *p)
		{
		current_kprobe = p;
		}

		int arch_prepare_kprobe(struct kprobe *p)
		{
		unsigned long addr = (unsigned long) p->addr;
		@@ -436,8 +453,18 @@ static int pre_kprobes_handler(struct die_args *args)
		unlock_kprobes();
		goto no_kprobe;
		}
		arch_disarm_kprobe(p);
		ret = 1;
		/* We have reentered the pre_kprobe_handler(), since
		* another probe was hit while within the handler.
		* We here save the original kprobes variables and
		* just single step on the instruction of the new probe
		* without calling any user handlers.
		*/
		save_previous_kprobe();
		set_current_kprobe(p);
		p->nmissed++;
		prepare_ss(p, regs);
		kprobe_status = KPROBE_REENTER;
		return 1;
		} else if (args->err == __IA64_BREAK_JPROBE) {
		/*
		* jprobe instrumented function just completed
		@@ -460,7 +487,7 @@ static int pre_kprobes_handler(struct die_args *args)
		}

		kprobe_status = KPROBE_HIT_ACTIVE;
		current_kprobe = p;
		set_current_kprobe(p);

		if (p->pre_handler && p->pre_handler(p, regs))
		/*
		@@ -485,12 +512,22 @@ static int post_kprobes_handler(struct pt_regs *regs)
		if (!kprobe_running())
		return 0;

		if (current_kprobe->post_handler)
		if ((kprobe_status != KPROBE_REENTER) && current_kprobe->post_handler) {
		kprobe_status = KPROBE_HIT_SSDONE;
		current_kprobe->post_handler(current_kprobe, regs, 0);
		}

		resume_execution(current_kprobe, regs);

		/Restore back the original saved kprobes variables and continue. /
		if (kprobe_status == KPROBE_REENTER) {
		restore_previous_kprobe();
		goto out;
		}

		unlock_kprobes();

		out:
		preempt_enable_no_resched();
		return 1;
		}

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