Message ID | 20241129090040.2690691-1-elver@google.com (mailing list archive) |
---|---|
State | New |
Headers | show |
Series | [bpf-next,v4,1/2] bpf: Remove bpf_probe_write_user() warning message | expand |
On 11/29/24 9:59 AM, Marco Elver wrote: > The warning message for bpf_probe_write_user() was introduced in > 96ae52279594 ("bpf: Add bpf_probe_write_user BPF helper to be called in > tracers"), with the following in the commit message: > > Given this feature is meant for experiments, and it has a risk of > crashing the system, and running programs, we print a warning on > when a proglet that attempts to use this helper is installed, > along with the pid and process name. > > After 8 years since 96ae52279594, bpf_probe_write_user() has found > successful applications beyond experiments [1, 2], with no other good > alternatives. Despite its intended purpose for "experiments", that > doesn't stop Hyrum's law, and there are likely many more users depending > on this helper: "[..] it does not matter what you promise [..] all > observable behaviors of your system will be depended on by somebody." > > The ominous "helper that may corrupt user memory!" has offered no real > benefit, and has been found to lead to confusion where the system > administrator is loading programs with valid use cases. > > As such, remove the warning message. > > Link: https://lore.kernel.org/lkml/20240404190146.1898103-1-elver@google.com/ [1] > Link: https://lore.kernel.org/r/lkml/CAAn3qOUMD81-vxLLfep0H6rRd74ho2VaekdL4HjKq+Y1t9KdXQ@mail.gmail.com/ [2] > Link: https://lore.kernel.org/all/CAEf4Bzb4D_=zuJrg3PawMOW3KqF8JvJm9SwF81_XHR2+u5hkUg@mail.gmail.com/ > Signed-off-by: Marco Elver <elver@google.com> > Acked-by: Jiri Olsa <jolsa@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Hello: This series was applied to bpf/bpf-next.git (master) by Alexei Starovoitov <ast@kernel.org>: On Fri, 29 Nov 2024 09:59:33 +0100 you wrote: > The warning message for bpf_probe_write_user() was introduced in > 96ae52279594 ("bpf: Add bpf_probe_write_user BPF helper to be called in > tracers"), with the following in the commit message: > > Given this feature is meant for experiments, and it has a risk of > crashing the system, and running programs, we print a warning on > when a proglet that attempts to use this helper is installed, > along with the pid and process name. > > [...] Here is the summary with links: - [bpf-next,v4,1/2] bpf: Remove bpf_probe_write_user() warning message https://git.kernel.org/bpf/bpf-next/c/3389f8243a90 - [bpf-next,v4,2/2] bpf: Refactor bpf_tracing_func_proto() and remove bpf_get_probe_write_proto() https://git.kernel.org/bpf/bpf-next/c/45e04eb4d9d8 You are awesome, thank you!
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 630b763e5240..0ab56af2e298 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -362,9 +362,6 @@ static const struct bpf_func_proto *bpf_get_probe_write_proto(void) if (!capable(CAP_SYS_ADMIN)) return NULL; - pr_warn_ratelimited("%s[%d] is installing a program with bpf_probe_write_user helper that may corrupt user memory!", - current->comm, task_pid_nr(current)); - return &bpf_probe_write_user_proto; }