path: root/Documentation/bpf
diff options
authorAlan Maguire <>2020-08-07 12:50:29 +0100
committerDaniel Borkmann <>2020-08-07 18:44:56 +0200
commit7fb20f9e901e6df2f7dc032d88da5abff4117d37 (patch)
tree056b7d8a81a622376a675a16c2404e7474263595 /Documentation/bpf
parent929e54a989680c6f134b02293732030b897475dc (diff)
bpf, doc: Remove references to warning message when using bpf_trace_printk()
The BPF helper bpf_trace_printk() no longer uses trace_printk(); it is now triggers a dedicated trace event. Hence the described warning is no longer present, so remove the discussion of it as it may confuse people. Fixes: ac5a72ea5c89 ("bpf: Use dedicated bpf_trace_printk event instead of trace_printk()") Signed-off-by: Alan Maguire <> Signed-off-by: Daniel Borkmann <> Link:
Diffstat (limited to 'Documentation/bpf')
1 files changed, 0 insertions, 11 deletions
diff --git a/Documentation/bpf/bpf_design_QA.rst b/Documentation/bpf/bpf_design_QA.rst
index 12a246fcf6cb..2df7b067ab93 100644
--- a/Documentation/bpf/bpf_design_QA.rst
+++ b/Documentation/bpf/bpf_design_QA.rst
@@ -246,17 +246,6 @@ program is loaded the kernel will print warning message, so
this helper is only useful for experiments and prototypes.
Tracing BPF programs are root only.
-Q: bpf_trace_printk() helper warning
-Q: When bpf_trace_printk() helper is used the kernel prints nasty
-warning message. Why is that?
-A: This is done to nudge program authors into better interfaces when
-programs need to pass data to user space. Like bpf_perf_event_output()
-can be used to efficiently stream data via perf ring buffer.
-BPF maps can be used for asynchronous data sharing between kernel
-and user space. bpf_trace_printk() should only be used for debugging.
Q: New functionality via kernel modules?
Q: Can BPF functionality such as new program or map types, new