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function_graph: Add pid tracing back to function graph tracer

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Now that the function_graph has a main callback that handles the function
graph subops tracing, it no longer honors the pid filtering of ftrace. Add
back this logic in the function_graph code to update the gops callback for
the entry function to test if it should trace the current task or not.

Link: https://lore.kernel.org/linux-trace-kernel/20240603190822.991720703@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Guo Ren <guoren@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt (Google) 2024-06-03 15:07:17 -04:00
parent c132be2c4f
commit df3ec5da6a
4 changed files with 47 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/linux/ftrace.h
View File

@ -1040,6 +1040,7 @@ typedef int (*trace_func_graph_ent_t)(struct ftrace_graph_ent *,
struct fgraph_ops *); /* entry */
extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace, struct fgraph_ops *gops);
bool ftrace_pids_enabled(struct ftrace_ops *ops);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
@ -1048,6 +1049,7 @@ struct fgraph_ops {
trace_func_graph_ret_t retfunc;
struct ftrace_ops ops; /* for the hash lists */
void *private;
trace_func_graph_ent_t saved_func;
int idx;
};

40
kernel/trace/fgraph.c
View File

@ -854,6 +854,41 @@ void ftrace_graph_exit_task(struct task_struct *t)
kfree(ret_stack);
}
static int fgraph_pid_func(struct ftrace_graph_ent *trace,
struct fgraph_ops *gops)
{
struct trace_array *tr = gops->ops.private;
int pid;
if (tr) {
pid = this_cpu_read(tr->array_buffer.data->ftrace_ignore_pid);
if (pid == FTRACE_PID_IGNORE)
return 0;
if (pid != FTRACE_PID_TRACE &&
pid != current->pid)
return 0;
}
return gops->saved_func(trace, gops);
}
void fgraph_update_pid_func(void)
{
struct fgraph_ops *gops;
struct ftrace_ops *op;
if (!(graph_ops.flags & FTRACE_OPS_FL_INITIALIZED))
return;
list_for_each_entry(op, &graph_ops.subop_list, list) {
if (op->flags & FTRACE_OPS_FL_PID) {
gops = container_of(op, struct fgraph_ops, ops);
gops->entryfunc = ftrace_pids_enabled(op) ?
fgraph_pid_func : gops->saved_func;
}
}
}
/* Allocate a return stack for each task */
static int start_graph_tracing(void)
{
@ -931,11 +966,15 @@ int register_ftrace_graph(struct fgraph_ops *gops)
command = FTRACE_START_FUNC_RET;
}
/* Always save the function, and reset at unregistering */
gops->saved_func = gops->entryfunc;
ret = ftrace_startup_subops(&graph_ops, &gops->ops, command);
error:
if (ret) {
fgraph_array[i] = &fgraph_stub;
ftrace_graph_active--;
gops->saved_func = NULL;
}
out:
mutex_unlock(&ftrace_lock);
@ -979,5 +1018,6 @@ void unregister_ftrace_graph(struct fgraph_ops *gops)
unregister_trace_sched_switch(ftrace_graph_probe_sched_switch, NULL);
}
out:
gops->saved_func = NULL;
mutex_unlock(&ftrace_lock);
}

5
kernel/trace/ftrace.c
View File

@ -100,7 +100,7 @@ struct ftrace_ops *function_trace_op __read_mostly = &ftrace_list_end;
/* What to set function_trace_op to */
static struct ftrace_ops *set_function_trace_op;
static bool ftrace_pids_enabled(struct ftrace_ops *ops)
bool ftrace_pids_enabled(struct ftrace_ops *ops)
{
struct trace_array *tr;
@ -402,10 +402,11 @@ static void ftrace_update_pid_func(void)
if (op->flags & FTRACE_OPS_FL_PID) {
op->func = ftrace_pids_enabled(op) ?
ftrace_pid_func : op->saved_func;
ftrace_update_trampoline(op);
}
} while_for_each_ftrace_op(op);
fgraph_update_pid_func();
update_ftrace_function();
}

2
kernel/trace/ftrace_internal.h
View File

@ -43,8 +43,10 @@ ftrace_ops_test(struct ftrace_ops *ops, unsigned long ip, void *regs)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
extern int ftrace_graph_active;
extern void fgraph_update_pid_func(void);
#else /* !CONFIG_FUNCTION_GRAPH_TRACER */
# define ftrace_graph_active 0
static inline void fgraph_update_pid_func(void) {}
#endif /* CONFIG_FUNCTION_GRAPH_TRACER */
#else /* !CONFIG_FUNCTION_TRACER */