tracing: Make tp_printk work on syscall tracepoints

[ Upstream commit cb1c45fb68b8a4285ccf750842b1136f26cfe267 ]

Currently the tp_printk option has no effect on syscall tracepoint.
When adding the kernel option parameter tp_printk, then:

echo 1 > /sys/kernel/debug/tracing/events/syscalls/enable

When running any application, no trace information is printed on the
terminal.

Now added printk for syscall tracepoints.

Link: https://lkml.kernel.org/r/20220410145025.681144-1-xiehuan09@gmail.com
Signed-off-by: Jeff Xie <xiehuan09@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index f755bde..b69e207 100644 (file)
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -154,7 +154,7 @@ print_syscall_enter(struct trace_iterator *iter, int flags,
                        goto end;
 
                /* parameter types */
-               if (tr->trace_flags & TRACE_ITER_VERBOSE)
+               if (tr && tr->trace_flags & TRACE_ITER_VERBOSE)
                        trace_seq_printf(s, "%s ", entry->types[i]);
 
                /* parameter values */
@@ -296,9 +296,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
        struct trace_event_file *trace_file;
        struct syscall_trace_enter *entry;
        struct syscall_metadata *sys_data;
-       struct ring_buffer_event *event;
-       struct trace_buffer *buffer;
-       unsigned int trace_ctx;
+       struct trace_event_buffer fbuffer;
        unsigned long args[6];
        int syscall_nr;
        int size;
@@ -321,20 +319,16 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
 
        size = sizeof(*entry) + sizeof(unsigned long) * sys_data->nb_args;
 
-       trace_ctx = tracing_gen_ctx();
-
-       event = trace_event_buffer_lock_reserve(&buffer, trace_file,
-                       sys_data->enter_event->event.type, size, trace_ctx);
-       if (!event)
+       entry = trace_event_buffer_reserve(&fbuffer, trace_file, size);
+       if (!entry)
                return;
 
-       entry = ring_buffer_event_data(event);
+       entry = ring_buffer_event_data(fbuffer.event);
        entry->nr = syscall_nr;
        syscall_get_arguments(current, regs, args);
        memcpy(entry->args, args, sizeof(unsigned long) * sys_data->nb_args);
 
-       event_trigger_unlock_commit(trace_file, buffer, event, entry,
-                                   trace_ctx);
+       trace_event_buffer_commit(&fbuffer);
 }
 
 static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
@@ -343,9 +337,7 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
        struct trace_event_file *trace_file;
        struct syscall_trace_exit *entry;
        struct syscall_metadata *sys_data;
-       struct ring_buffer_event *event;
-       struct trace_buffer *buffer;
-       unsigned int trace_ctx;
+       struct trace_event_buffer fbuffer;
        int syscall_nr;
 
        syscall_nr = trace_get_syscall_nr(current, regs);
@@ -364,20 +356,15 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
        if (!sys_data)
                return;
 
-       trace_ctx = tracing_gen_ctx();
-
-       event = trace_event_buffer_lock_reserve(&buffer, trace_file,
-                       sys_data->exit_event->event.type, sizeof(*entry),
-                       trace_ctx);
-       if (!event)
+       entry = trace_event_buffer_reserve(&fbuffer, trace_file, sizeof(*entry));
+       if (!entry)
                return;
 
-       entry = ring_buffer_event_data(event);
+       entry = ring_buffer_event_data(fbuffer.event);
        entry->nr = syscall_nr;
        entry->ret = syscall_get_return_value(current, regs);
 
-       event_trigger_unlock_commit(trace_file, buffer, event, entry,
-                                   trace_ctx);
+       trace_event_buffer_commit(&fbuffer);
 }
 
 static int reg_event_syscall_enter(struct trace_event_file *file,