[PATCH 6/8] tracing/ftrace: Add might_fault check to syscall probes
From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: 2024-09-09 20:17:19
Also in:
bpf, lkml
Subsystem:
the rest, tracing · Maintainers:
Linus Torvalds, Steven Rostedt, Masami Hiramatsu
Add a might_fault() check to validate that the ftrace sys_enter/sys_exit probe callbacks are indeed called from a context where page faults can be handled. 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/trace_events.h | 1 + kernel/trace/trace_syscalls.c | 2 ++ 2 files changed, 3 insertions(+)
diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h
index 0228d9ed94a3..e0d4850b0d77 100644
--- a/include/trace/trace_events.h
+++ b/include/trace/trace_events.h@@ -446,6 +446,7 @@ __DECLARE_EVENT_CLASS(call, PARAMS(proto), PARAMS(args), PARAMS(tstruct), \ static notrace void \ trace_event_raw_event_##call(void *__data, proto) \ { \ + might_fault(); \ guard(preempt_notrace)(); \ do_trace_event_raw_event_##call(__data, args); \ }
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index a3d8ac00793e..0430890cbb42 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c@@ -303,6 +303,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id) * Syscall probe called with preemption enabled, but the ring * buffer and per-cpu data require preemption to be disabled. */ + might_fault(); guard(preempt_notrace)(); syscall_nr = trace_get_syscall_nr(current, regs);
@@ -348,6 +349,7 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret) * Syscall probe called with preemption enabled, but the ring * buffer and per-cpu data require preemption to be disabled. */ + might_fault(); guard(preempt_notrace)(); syscall_nr = trace_get_syscall_nr(current, regs);
--
2.39.2