diff mbox series

[for-next,04/10] tracing/bpf: disable preemption in syscall probe

Message ID 20241010142550.191163490@goodmis.org (mailing list archive)
State Not Applicable
Headers show
Series [for-next,01/10] tracing: Declare system call tracepoints with TRACE_EVENT_SYSCALL | expand

Commit Message

Steven Rostedt Oct. 10, 2024, 2:25 p.m. UTC 
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

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.

Cc: Michael Jeanson <mjeanson@efficios.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
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 <andrii.nakryiko@gmail.com>
Cc: bpf@vger.kernel.org
Cc: Joel Fernandes <joel@joelfernandes.org>
Link: https://lore.kernel.org/20241009010718.2050182-5-mathieu.desnoyers@efficios.com
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Andrii Nakryiko <andrii@kernel.org> # BPF parts
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
---
 include/trace/bpf_probe.h | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/include/trace/bpf_probe.h b/include/trace/bpf_probe.h
index c85bbce5aaa5..fec97c93e1c9 100644
--- a/include/trace/bpf_probe.h
+++ b/include/trace/bpf_probe.h
@@ -53,8 +53,18 @@  __bpf_trace_##call(void *__data, proto)					\
 #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print)	\
 	__BPF_DECLARE_TRACE(call, PARAMS(proto), PARAMS(args))
 
+#define __BPF_DECLARE_TRACE_SYSCALL(call, proto, args)			\
+static notrace void							\
+__bpf_trace_##call(void *__data, proto)					\
+{									\
+	preempt_disable_notrace();					\
+	CONCATENATE(bpf_trace_run, COUNT_ARGS(args))(__data, CAST_TO_U64(args));	\
+	preempt_enable_notrace();					\
+}
+
 #undef DECLARE_EVENT_SYSCALL_CLASS
-#define DECLARE_EVENT_SYSCALL_CLASS DECLARE_EVENT_CLASS
+#define DECLARE_EVENT_SYSCALL_CLASS(call, proto, args, tstruct, assign, print)	\
+	__BPF_DECLARE_TRACE_SYSCALL(call, PARAMS(proto), PARAMS(args))
 
 /*
  * This part is compiled out, it is only here as a build time check