On Thu, 3 Oct 2024 11:16:37 -0400 Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote: > Add a might_fault() check to validate that the perf 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@xxxxxxxxxxxx> > Cc: Michael Jeanson <mjeanson@xxxxxxxxxxxx> > Cc: Steven Rostedt <rostedt@xxxxxxxxxxx> > Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Alexei Starovoitov <ast@xxxxxxxxxx> > Cc: Yonghong Song <yhs@xxxxxx> > Cc: Paul E. McKenney <paulmck@xxxxxxxxxx> > Cc: Ingo Molnar <mingo@xxxxxxxxxx> > Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> > Cc: Mark Rutland <mark.rutland@xxxxxxx> > Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> > Cc: Namhyung Kim <namhyung@xxxxxxxxxx> > Cc: Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> > Cc: bpf@xxxxxxxxxxxxxxx > Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> > --- > include/trace/perf.h | 1 + > kernel/trace/trace_syscalls.c | 2 ++ > 2 files changed, 3 insertions(+) > > diff --git a/include/trace/perf.h b/include/trace/perf.h > index 5650c1bad088..321bfd7919f6 100644 > --- a/include/trace/perf.h > +++ b/include/trace/perf.h > @@ -84,6 +84,7 @@ perf_trace_##call(void *__data, proto) \ > u64 __count __attribute__((unused)); \ > struct task_struct *__task __attribute__((unused)); \ > \ > + might_fault(); \ > guard(preempt_notrace)(); \ > do_perf_trace_##call(__data, args); \ Same for this. This is used for all tracepoints that perf hooks to. -- Steve > } > diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c > index 89d7e4c57b5b..0d42d6f293d6 100644 > --- a/kernel/trace/trace_syscalls.c > +++ b/kernel/trace/trace_syscalls.c > @@ -602,6 +602,7 @@ static void perf_syscall_enter(void *ignore, 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); > @@ -710,6 +711,7 @@ static void perf_syscall_exit(void *ignore, 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);
