Re: [PATCH net] trace/bpf: remove helper bpf_perf_prog_read_value from tracepoint type programs
flat view
From: Daniel Borkmann <daniel@iogearbox.net>
Date: 2018-03-20 22:21:02
On 03/20/2018 07:19 PM, Yonghong Song wrote:
Commit 4bebdc7a85aa ("bpf: add helper bpf_perf_prog_read_value")
added helper bpf_perf_prog_read_value so that perf_event type program
can read event counter and enabled/running time.
This commit, however, introduced a bug which allows this helper
for tracepoint type programs. This is incorrect as bpf_perf_prog_read_value
needs to access perf_event through its bpf_perf_event_data_kern type context,
which is not available for tracepoint type program.
This patch fixed the issue by separating bpf_func_proto between tracepoint
and perf_event type programs and removed bpf_perf_prog_read_value
from tracepoint func prototype.
Fixes: Commit 4bebdc7a85aa ("bpf: add helper bpf_perf_prog_read_value")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Yonghong Song <redacted>Sigh, also makes sense to split given this is so subtle. Applied to bpf, thanks Yonghong!