commit 08765a9a0ba8dc9c38ec7dff05fa1734cf43866f
author Hengqi Chen <chenhengqi@outlook.com> Sun Oct 31 23:20:10 2021 +0800
committer yonghong-song <ys114321@gmail.com> Mon Nov 01 08:07:53 2021 -0700
tree 288ede71ad7cd518fb8a8b49869c2ef2c8b570af
parent 8270cf28bcd41107b71160fa609ec6a50b405f0a

bcc/tools: Fix renaming of the state field of task_struct

Kernel commit 2f064a59a1 ("sched: Change task_struct::state") changes
the name of task_struct::state to task_struct::__state, which breaks
several bcc tools. Fix this issue by checking field existence in vmlinux
BTF. Since this change was intruduce in kernel v5.14, we should have
BTF support. Closes #3658 .

Signed-off-by: Hengqi Chen <chenhengqi@outlook.com>

tools/runqlat.py

diff --git a/tools/runqlat.py b/tools/runqlat.py
index a5c261a..9edd7be 100755
--- a/tools/runqlat.py
+++ b/tools/runqlat.py
@@ -156,7 +156,7 @@
     u32 pid, tgid;
 
     // ivcsw: treat like an enqueue event and store timestamp
-    if (prev->state == TASK_RUNNING) {
+    if (prev->STATE_FIELD == TASK_RUNNING) {
         tgid = prev->tgid;
         pid = prev->pid;
         if (!(FILTER || pid == 0)) {
@@ -210,7 +210,7 @@
     u32 pid, tgid;
 
     // ivcsw: treat like an enqueue event and store timestamp
-    if (prev->state == TASK_RUNNING) {
+    if (prev->STATE_FIELD == TASK_RUNNING) {
         tgid = prev->tgid;
         pid = prev->pid;
         if (!(FILTER || pid == 0)) {
@@ -248,6 +248,10 @@
     bpf_text += bpf_text_kprobe
 
 # code substitutions
+if BPF.kernel_struct_has_field(b'task_struct', b'__state') == 1:
+    bpf_text = bpf_text.replace('STATE_FIELD', '__state')
+else:
+    bpf_text = bpf_text.replace('STATE_FIELD', 'state')
 if args.pid:
     # pid from userspace point of view is thread group from kernel pov
     bpf_text = bpf_text.replace('FILTER', 'tgid != %s' % args.pid)