Commit 89480801 authored by Martin Schwidefsky's avatar Martin Schwidefsky Committed by Martin Schwidefsky
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[S390] kprobes: Fix the return address of multiple kretprobes 



Analog to git commit 737480a0
fix the return address of subsequent kretprobes when multiple
kretprobes are set on the same function.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent adb45839

arch/s390/kernel/kprobes.c

+26 −3
Original line number Diff line number Diff line
@@ -349,6 +349,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p, 
	struct hlist_node *node, *tmp;

	unsigned long flags, orig_ret_address = 0;

	unsigned long trampoline_address = (unsigned long)&kretprobe_trampoline;

	kprobe_opcode_t *correct_ret_addr = NULL;



	INIT_HLIST_HEAD(&empty_rp);

	kretprobe_hash_lock(current, &head, &flags);
@@ -371,10 +372,32 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p, 
			/* another task is sharing our hash bucket */

			continue;



		if (ri->rp && ri->rp->handler)

			ri->rp->handler(ri, regs);

		orig_ret_address = (unsigned long)ri->ret_addr;



		if (orig_ret_address != trampoline_address)

			/*

			 * This is the real return address. Any other

			 * instances associated with this task are for

			 * other calls deeper on the call stack

			 */

			break;

	}



	kretprobe_assert(ri, orig_ret_address, trampoline_address);



	correct_ret_addr = ri->ret_addr;

	hlist_for_each_entry_safe(ri, node, tmp, head, hlist) {

		if (ri->task != current)

			/* another task is sharing our hash bucket */

			continue;



		orig_ret_address = (unsigned long)ri->ret_addr;



		if (ri->rp && ri->rp->handler) {

			ri->ret_addr = correct_ret_addr;

			ri->rp->handler(ri, regs);

		}



		recycle_rp_inst(ri, &empty_rp);



		if (orig_ret_address != trampoline_address) {
@@ -386,7 +409,7 @@ static int __kprobes trampoline_probe_handler(struct kprobe *p, 
			break;

		}

	}

	kretprobe_assert(ri, orig_ret_address, trampoline_address);



	regs->psw.addr = orig_ret_address | PSW_ADDR_AMODE;



	reset_current_kprobe();