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| author | Josef Bacik <jbacik@fb.com> | 2017-11-07 15:28:42 -0500 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-11-11 12:18:05 +0900 |
| commit | dd0bb688eaa241b5655d396d45366cba9225aed9 (patch) | |
| tree | 80e320112959e90d474fd20e644b8377217dad0b /kernel/events | |
| parent | 54985120a1c461b74f9510e5d730971f2a2383b1 (diff) | |
| download | linux-dd0bb688eaa241b5655d396d45366cba9225aed9.tar.gz | |
bpf: add a bpf_override_function helper
Error injection is sloppy and very ad-hoc. BPF could fill this niche perfectly with it's kprobe functionality. We could make sure errors are only triggered in specific call chains that we care about with very specific situations. Accomplish this with the bpf_override_funciton helper. This will modify the probe'd callers return value to the specified value and set the PC to an override function that simply returns, bypassing the originally probed function. This gives us a nice clean way to implement systematic error injection for all of our code paths. Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Josef Bacik <jbacik@fb.com> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/events')
| -rw-r--r-- | kernel/events/core.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index 42d24bd64ea4..ac240d31b5bf 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -8171,6 +8171,13 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd) return -EINVAL; } + /* Kprobe override only works for kprobes, not uprobes. */ + if (prog->kprobe_override && + !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) { + bpf_prog_put(prog); + return -EINVAL; + } + if (is_tracepoint || is_syscall_tp) { int off = trace_event_get_offsets(event->tp_event); |