Kprobes: print details of kretprobe on assertion failure

In certain cases like when the real return address can't be found or when
the number of tracked calls to a kretprobed function is less than the
number of returns, we may not be able to find the correct return address
after processing a kretprobe.  Currently we just do a BUG_ON, but no
information is provided about the actual failing kretprobe.

Print out details of the kretprobe before calling BUG().

Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: Maneesh Soni <maneesh@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 2 deletions

diff --git a/arch/i386/kernel/kprobes.c b/arch/i386/kernel/kprobes.c
index e00f75ecf1a8..3fbef288c376 100644
--- a/arch/i386/kernel/kprobes.c
+++ b/arch/i386/kernel/kprobes.c
@@ -449,8 +449,7 @@ fastcall void *__kprobes trampoline_handler(struct pt_regs *regs)
                         break;
         }
 
-        BUG_ON(!orig_ret_address || (orig_ret_address == trampoline_address));
-
+        kretprobe_assert(ri, orig_ret_address, trampoline_address);
         spin_unlock_irqrestore(&kretprobe_lock, flags);
 
         hlist_for_each_entry_safe(ri, node, tmp, &empty_rp, hlist) {