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kernel-2.6.18-238.el5.src.rpm

From: Dave Anderson <anderson@redhat.com>
Date: Wed, 23 Jan 2008 15:18:30 -0500
Subject: [misc] kprobes: make probe handler stack unwind correct
Message-id: 4797A116.7080601@redhat.com
O-Subject: [RHEL5.2 PATCH 1/4] kprobes: BZ #232489: need kprobes improvement patches
Bugzilla: 232489

BZ #232489: need kprobes improvement patches
https://bugzilla.redhat.com/show_bug.cgi?id=232489
linux-2.6.git-3661999a17b0397c7a93c200b280c55958ba3593

Backport of this ia64-specific commit:

   commit 3661999a17b0397c7a93c200b280c55958ba3593
   Author: Shaohua Li <shaohua.li@intel.com>
   Date:   Tue Nov 13 14:55:20 2007 +0800

   [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: Shaohua Li <shaohua.li@intel.com>
   Signed-off-by: Tony Luck <tony.luck@intel.com>

Tested on ia64 by: Masami Hiramatsu (mhiramat@redhat.com)

diff --git a/arch/ia64/kernel/kprobes.c b/arch/ia64/kernel/kprobes.c
index 5fcfc6c..4f87e63 100644
--- a/arch/ia64/kernel/kprobes.c
+++ b/arch/ia64/kernel/kprobes.c
@@ -359,6 +359,23 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 			/* 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 */
+			continue;
+
 		if (ri->rp && ri->rp->handler)
 			ri->rp->handler(ri, regs);
 
@@ -375,7 +392,6 @@ int __kprobes trampoline_probe_handler(struct kprobe *p, struct pt_regs *regs)
 	}
 
 	BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
-	regs->cr_iip = orig_ret_address;
 
 	reset_current_kprobe();
 	spin_unlock_irqrestore(&kretprobe_lock, flags);