[PATCH 26/35] perf tools: Handle injected guest kernel mmap event

Adrian Hunter
2022-07-11T10:14:08Z

If a kernel mmap event was recorded inside a guest and injected into a host
perf.data file, then it will match a host mmap_name not a guest mmap_name,
see machine__set_mmap_name(). So try matching a host mmap_name in that
case.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
tools/perf/util/machine.c | 15 ++++++++++++---
1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 27d1a38f44c3..8f657225fb02 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1742,6 +1742,7 @@ static int machine__process_kernel_mmap_event(struct machine *machine,
struct map *map;
enum dso_space_type dso_space;
bool is_kernel_mmap;
+ const char *mmap_name = machine->mmap_name;

/* If we have maps from kcore then we do not need or want any others */
if (machine__uses_kcore(machine))
@@ -1752,8 +1753,16 @@ static int machine__process_kernel_mmap_event(struct machine *machine,
else
dso_space = DSO_SPACE__KERNEL_GUEST;

- is_kernel_mmap = memcmp(xm->name, machine->mmap_name,
- strlen(machine->mmap_name) - 1) == 0;
+ is_kernel_mmap = memcmp(xm->name, mmap_name, strlen(mmap_name) - 1) == 0;
+ if (!is_kernel_mmap && !machine__is_host(machine)) {
+ /*
+ * If the event was recorded inside the guest and injected into
+ * the host perf.data file, then it will match a host mmap_name,
+ * so try that - see machine__set_mmap_name().
+ */
+ mmap_name = "[kernel.kallsyms]";
+ is_kernel_mmap = memcmp(xm->name, mmap_name, strlen(mmap_name) - 1) == 0;
+ }
if (xm->name[0] == '/' ||
(!is_kernel_mmap && xm->name[0] == '[')) {
map = machine__addnew_module_map(machine, xm->start,
@@ -1767,7 +1776,7 @@ static int machine__process_kernel_mmap_event(struct machine *machine,
dso__set_build_id(map->dso, bid);

} else if (is_kernel_mmap) {
- const char *symbol_name = (xm->name + strlen(machine->mmap_name));
+ const char *symbol_name = xm->name + strlen(mmap_name);
/*
* Should be there already, from the build-id table in
* the header.
--
2.25.1