From: Alan Maguire alan.maguire@oracle.com
mainline inclusion from mainline-v5.9-rc1 commit 7fb20f9e901e6df2f7dc032d88da5abff4117d37 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4PKDW CVE: NA
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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 alan.maguire@oracle.com Signed-off-by: Daniel Borkmann daniel@iogearbox.net Link: https://lore.kernel.org/bpf/1596801029-32395-1-git-send-email-alan.maguire@o... Signed-off-by: Liu Xinpeng liuxp11@chinatelecom.cn # openEuler_contributor Signed-off-by: Ctyun Kernel ctyuncommiter01@chinatelecom.cn # openEuler_contributor Signed-off-by: Pu Lehui pulehui@huawei.com Reviewed-by: Yang Jihong yangjihong1@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- Documentation/bpf/bpf_design_QA.rst | 11 ----------- 1 file changed, 11 deletions(-)
diff --git a/Documentation/bpf/bpf_design_QA.rst b/Documentation/bpf/bpf_design_QA.rst index e2cc405acddb5..bc405f7772111 100644 --- a/Documentation/bpf/bpf_design_QA.rst +++ b/Documentation/bpf/bpf_design_QA.rst @@ -208,17 +208,6 @@ 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