commit 90f2086c8dd073792b0be382944440e3d0f1977f
author Yonghong Song <yhs@fb.com> Wed Nov 27 09:16:23 2019 -0800
committer yonghong-song <ys114321@gmail.com> Wed Nov 27 10:09:54 2019 -0800
tree 8115f62582a8a5888766223b405be5f8dbbb5671
parent a1a04f49ac736bc0ddd341258b8a56f2a25d30c5

do not use BPF_F_REUSE_STACKID incorrectly

Do not use BPF_F_REUSE_STACKID if the stack id is used
together with process specific info like
pid/tgid/comm. Using BPF_F_REUSE_STACKID may cause
stack id pointing to a different stack later on.

Signed-off-by: Yonghong Song <yhs@fb.com>

tools/trace.py

diff --git a/tools/trace.py b/tools/trace.py
index 1f4f589..0bd2861 100755
--- a/tools/trace.py
+++ b/tools/trace.py
@@ -487,12 +487,12 @@
                 if self.user_stack:
                         stack_trace += """
         __data.user_stack_id = %s.get_stackid(
-          %s, BPF_F_REUSE_STACKID | BPF_F_USER_STACK
+          %s, BPF_F_USER_STACK
         );""" % (self.stacks_name, ctx_name)
                 if self.kernel_stack:
                         stack_trace += """
         __data.kernel_stack_id = %s.get_stackid(
-          %s, BPF_F_REUSE_STACKID
+          %s, 0
         );""" % (self.stacks_name, ctx_name)
 
                 text = heading + """