[PATCH] jprobes: Ensure that the probepoint is at function entry

[Naveen N. Rao]

Similar to commit 90ec5e89e393c ("kretprobes: Ensure probe location is
at function entry"), ensure that the jprobe probepoint is at function
entry.

Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
---
 kernel/kprobes.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/kernel/kprobes.c b/kernel/kprobes.c
index adfe3b4cfe05..950018609339 100644
--- a/kernel/kprobes.c
+++ b/kernel/kprobes.c
@@ -1776,9 +1776,14 @@ int register_jprobes(struct jprobe **jps, int num)
 		jp = jps[i];
 		addr = arch_deref_entry_point(jp->entry);
 
-		/* Verify probepoint is a function entry point */
+		/*
+		 * Verify probepoint as well as the jprobe handler are
+		 * function entry points.
+		 */
 		if (kallsyms_lookup_size_offset(addr, NULL, &offset) &&
-		    offset == 0) {
+				offset == 0 &&
+				function_offset_within_entry(jp->kp.addr,
+					jp->kp.symbol_name, jp->kp.offset)) {
 			jp->kp.pre_handler = setjmp_pre_handler;
 			jp->kp.break_handler = longjmp_break_handler;
 			ret = register_kprobe(&jp->kp);
-- 
2.13.1