From a3742ff269a8d81cb116ec3dd22ef4516de06399 Mon Sep 17 00:00:00 2001
From: William Cohen <wcohen@redhat.com>
Date: Tue, 24 Sep 2019 09:59:12 -0400
Subject: [PATCH] Use the mmap offset to correctly compute the IP location in a
 file

Newer versions of binutils are now now splitting the file into
multiple mmap loads.  The assumption that the mmap for the executable
code in the file starts at the beginning of the file (that the file
offset is always zero) is no longer true.  The computation to convert
the IP address into an offset needs to also use the offset.
---
 libperf_events/operf_sfile.h   |  1 +
 libperf_events/operf_utils.cpp | 10 +++++++---
 2 files changed, 8 insertions(+), 3 deletions(-)

diff --git a/libperf_events/operf_sfile.h b/libperf_events/operf_sfile.h
index bc003553..4d0576c6 100644
--- a/libperf_events/operf_sfile.h
+++ b/libperf_events/operf_sfile.h
@@ -101,6 +101,7 @@ struct operf_transient {
 	u32 tgid;
 	vma_t start_addr;
 	vma_t end_addr;
+	u64 pgoff;
 	bool cg;
 	// TODO: handle extended
 	//void * ext;
diff --git a/libperf_events/operf_utils.cpp b/libperf_events/operf_utils.cpp
index 70253495..1e9d1e98 100644
--- a/libperf_events/operf_utils.cpp
+++ b/libperf_events/operf_utils.cpp
@@ -320,7 +320,8 @@ static void __handle_mmap_event(event_t * event)
 			cout << "PERF_RECORD_MMAP for process " << hex << event->mmap.pid << "/"
 			     << event->mmap.tid << ": " << event->mmap.filename << endl;
 			cout << "\tstart_addr: " << hex << mapping->start_addr
-			     << "; end addr: " << mapping->end_addr << endl;
+			     << "; end addr: " << mapping->end_addr
+			     << "; pgoff: " << mapping->pgoff << endl;
 		}
 
 		if (event->header.misc & PERF_RECORD_MISC_USER)
@@ -465,6 +466,7 @@ static struct operf_transient * __get_operf_trans(struct sample_data * data, boo
 		trans.image_len = strlen(trans.image_name);
 		trans.start_addr = op_mmap->start_addr;
 		trans.end_addr = op_mmap->end_addr;
+		trans.pgoff = op_mmap->pgoff;
 		trans.tgid = data->pid;
 		trans.tid = data->tid;
 		trans.cur_procinfo = proc;
@@ -474,7 +476,7 @@ static struct operf_transient * __get_operf_trans(struct sample_data * data, boo
 		if (trans.in_kernel || trans.is_anon)
 			trans.pc = data->ip;
 		else
-			trans.pc = data->ip - trans.start_addr;
+			trans.pc = data->ip + trans.pgoff - trans.start_addr;
 
 		trans.sample_id = data->id;
 		retval = &trans;
@@ -767,7 +769,7 @@ static int __handle_sample_event(event_t * event, u64 sample_type)
 		if (trans.is_anon)
 			trans.pc = data.ip;
 		else
-			trans.pc = data.ip - trans.start_addr;
+			trans.pc = data.ip + trans.pgoff - trans.start_addr;
 		found_trans = true;
 	}
 
@@ -1062,6 +1064,7 @@ void OP_perf_utils::op_get_vsyscall_mapping(pid_t tgid, int output_fd, operf_rec
 			size = align_64bit(size);
 			mmap.start = start_addr;
 			mmap.len = end_addr - mmap.start;
+			mmap.pgoff = offset;
 			mmap.pid = tgid;
 			mmap.tid = tgid;
 			mmap.header.size = (sizeof(mmap) -
@@ -1133,6 +1136,7 @@ void OP_perf_utils::op_record_process_exec_mmaps(pid_t pid, pid_t tgid, int outp
 			size = align_64bit(size);
 			mmap.start = start_addr;
 			mmap.len = end_addr - mmap.start;
+			mmap.pgoff = offset;
 			mmap.pid = tgid;
 			mmap.tid = pid;
 			mmap.header.size = (sizeof(mmap) -
-- 
2.21.0