| Message ID | 20241003151638.1608537-8-mathieu.desnoyers@efficios.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tracing: Allow system call tracepoints to handle page faults | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
On Thu, 3 Oct 2024 11:16:37 -0400 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> 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@efficios.com> > Cc: Michael Jeanson <mjeanson@efficios.com> > 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 <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> > --- > 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);
On 2024-10-04 00:37, Steven Rostedt wrote: > On Thu, 3 Oct 2024 11:16:37 -0400 > Mathieu Desnoyers <mathieu.desnoyers@efficios.com> 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@efficios.com> >> Cc: Michael Jeanson <mjeanson@efficios.com> >> 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 <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> >> --- >> 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. You're also missing the context: #undef DECLARE_EVENT_SYSCALL_CLASS #define DECLARE_EVENT_SYSCALL_CLASS(call, proto, args, tstruct, assign, print) \ __DECLARE_EVENT_CLASS(call, PARAMS(proto), PARAMS(args), PARAMS(tstruct), \ PARAMS(assign), PARAMS(print)) \ static notrace void \ 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); \ } Not an issue. Thanks, Mathieu > > -- 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); >
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); \ } 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);
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@efficios.com> Cc: Michael Jeanson <mjeanson@efficios.com> 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 <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> --- include/trace/perf.h | 1 + kernel/trace/trace_syscalls.c | 2 ++ 2 files changed, 3 insertions(+)