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Commit 3661999a authored by Shaohua Li's avatar Shaohua Li Committed by Tony Luck
Browse files

[IA64] kprobe: make kreturn probe handler stack unwind correct 

Restore regs->ccr_iip before kreturn probe handler runs. In this way, if
probe handler does unwind, unwind can correctly get the stack trace.

Fixes: http://sourceware.org/bugzilla/show_bug.cgi?id=5051



Signed-off-by: default avatarShaohua Li <shaohua.li@intel.com>
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent 965d7472

arch/ia64/kernel/kprobes.c

+17 −2
Original line number Diff line number Diff line
@@ -430,6 +430,23 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) 
	 *       real return address, and all the rest will point to

	 *       kretprobe_trampoline

	 */

	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 (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;

	}



	regs->cr_iip = orig_ret_address;



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

		if (ri->task != current)

			/* another task is sharing our hash bucket */
@@ -452,8 +469,6 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs) 


	kretprobe_assert(ri, orig_ret_address, trampoline_address);



	regs->cr_iip = orig_ret_address;



	reset_current_kprobe();

	spin_unlock_irqrestore(&kretprobe_lock, flags);

	preempt_enable_no_resched();