Re: [PATCH 4/8] tracing/bpf: guard syscall probe with preempt_notrace

On Mon, Sep 9, 2024 at 1:17 PM Mathieu Desnoyers
[off-list ref] wrote:

In preparation for allowing system call enter/exit instrumentation to
handle page faults, make sure that bpf can handle this change by
explicitly disabling preemption within the bpf system call tracepoint
probes to respect the current expectations within bpf tracing code.

This change does not yet allow bpf to take page faults per se within its
probe, but allows its existing probes to adapt to the upcoming change.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Michael Jeanson <redacted>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Yonghong Song <redacted>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Andrii Nakryiko <redacted>
Cc: bpf@vger.kernel.org
Cc: Joel Fernandes <redacted>
---
 include/trace/bpf_probe.h | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

LGTM.

Acked-by: Andrii Nakryiko <andrii@kernel.org>