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From: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Florent Revest <revest@chromium.org>
Cc: linux-trace-kernel@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	bpf <bpf@vger.kernel.org>, Sven Schnelle <svens@linux.ibm.com>,
	Alexei Starovoitov <ast@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Alan Maguire <alan.maguire@oracle.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>, Guo Ren <guoren@kernel.org>
Subject: [RFC PATCH v2 14/31] function_graph: Move set_graph_function tests to shadow stack global var
Date: Wed,  8 Nov 2023 23:27:04 +0900	[thread overview]
Message-ID: <169945362406.55307.7939383981224458445.stgit@devnote2> (raw)
In-Reply-To: <169945345785.55307.5003201137843449313.stgit@devnote2>

From: Steven Rostedt (VMware) <rostedt@goodmis.org>

The use of the task->trace_recursion for the logic used for the
set_graph_funnction was a bit of an abuse of that variable. Now that there
exists global vars that are per stack for registered graph traces, use that
instead.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
---
 include/linux/trace_recursion.h      |    5 +----
 kernel/trace/trace.h                 |   32 +++++++++++++++++++++-----------
 kernel/trace/trace_functions_graph.c |    6 +++---
 kernel/trace/trace_irqsoff.c         |    4 ++--
 kernel/trace/trace_sched_wakeup.c    |    4 ++--
 5 files changed, 29 insertions(+), 22 deletions(-)

diff --git a/include/linux/trace_recursion.h b/include/linux/trace_recursion.h
index d48cd92d2364..2efd5ec46d7f 100644
--- a/include/linux/trace_recursion.h
+++ b/include/linux/trace_recursion.h
@@ -44,9 +44,6 @@ enum {
  */
 	TRACE_IRQ_BIT,
 
-	/* Set if the function is in the set_graph_function file */
-	TRACE_GRAPH_BIT,
-
 	/*
 	 * In the very unlikely case that an interrupt came in
 	 * at a start of graph tracing, and we want to trace
@@ -60,7 +57,7 @@ enum {
 	 * that preempted a softirq start of a function that
 	 * preempted normal context!!!! Luckily, it can't be
 	 * greater than 3, so the next two bits are a mask
-	 * of what the depth is when we set TRACE_GRAPH_BIT
+	 * of what the depth is when we set TRACE_GRAPH_FL
 	 */
 
 	TRACE_GRAPH_DEPTH_START_BIT,
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index f77322e3b177..60d38709ab91 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -889,11 +889,16 @@ extern void init_array_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops
 extern int allocate_fgraph_ops(struct trace_array *tr, struct ftrace_ops *ops);
 extern void free_fgraph_ops(struct trace_array *tr);
 
+enum {
+	TRACE_GRAPH_FL		= 1,
+};
+
 #ifdef CONFIG_DYNAMIC_FTRACE
 extern struct ftrace_hash __rcu *ftrace_graph_hash;
 extern struct ftrace_hash __rcu *ftrace_graph_notrace_hash;
 
-static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
+static inline int
+ftrace_graph_addr(unsigned long *task_var, struct ftrace_graph_ent *trace)
 {
 	unsigned long addr = trace->func;
 	int ret = 0;
@@ -915,12 +920,11 @@ static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
 	}
 
 	if (ftrace_lookup_ip(hash, addr)) {
-
 		/*
 		 * This needs to be cleared on the return functions
 		 * when the depth is zero.
 		 */
-		trace_recursion_set(TRACE_GRAPH_BIT);
+		*task_var |= TRACE_GRAPH_FL;
 		trace_recursion_set_depth(trace->depth);
 
 		/*
@@ -940,11 +944,14 @@ static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
 	return ret;
 }
 
-static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+static inline void
+ftrace_graph_addr_finish(struct fgraph_ops *gops, struct ftrace_graph_ret *trace)
 {
-	if (trace_recursion_test(TRACE_GRAPH_BIT) &&
+	unsigned long *task_var = fgraph_get_task_var(gops);
+
+	if ((*task_var & TRACE_GRAPH_FL) &&
 	    trace->depth == trace_recursion_depth())
-		trace_recursion_clear(TRACE_GRAPH_BIT);
+		*task_var &= ~TRACE_GRAPH_FL;
 }
 
 static inline int ftrace_graph_notrace_addr(unsigned long addr)
@@ -971,7 +978,7 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr)
 }
 
 #else
-static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
+static inline int ftrace_graph_addr(unsigned long *task_var, struct ftrace_graph_ent *trace)
 {
 	return 1;
 }
@@ -980,17 +987,20 @@ static inline int ftrace_graph_notrace_addr(unsigned long addr)
 {
 	return 0;
 }
-static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace)
+static inline void ftrace_graph_addr_finish(struct fgraph_ops *gops, struct ftrace_graph_ret *trace)
 { }
 #endif /* CONFIG_DYNAMIC_FTRACE */
 
 extern unsigned int fgraph_max_depth;
 
-static inline bool ftrace_graph_ignore_func(struct ftrace_graph_ent *trace)
+static inline bool
+ftrace_graph_ignore_func(struct fgraph_ops *gops, struct ftrace_graph_ent *trace)
 {
+	unsigned long *task_var = fgraph_get_task_var(gops);
+
 	/* trace it when it is-nested-in or is a function enabled. */
-	return !(trace_recursion_test(TRACE_GRAPH_BIT) ||
-		 ftrace_graph_addr(trace)) ||
+	return !((*task_var & TRACE_GRAPH_FL) ||
+		 ftrace_graph_addr(task_var, trace)) ||
 		(trace->depth < 0) ||
 		(fgraph_max_depth && trace->depth >= fgraph_max_depth);
 }
diff --git a/kernel/trace/trace_functions_graph.c b/kernel/trace/trace_functions_graph.c
index 7f30652f0e97..66cce73e94f8 100644
--- a/kernel/trace/trace_functions_graph.c
+++ b/kernel/trace/trace_functions_graph.c
@@ -160,7 +160,7 @@ int trace_graph_entry(struct ftrace_graph_ent *trace,
 	if (!ftrace_trace_task(tr))
 		return 0;
 
-	if (ftrace_graph_ignore_func(trace))
+	if (ftrace_graph_ignore_func(gops, trace))
 		return 0;
 
 	if (ftrace_graph_ignore_irqs())
@@ -247,7 +247,7 @@ void trace_graph_return(struct ftrace_graph_ret *trace,
 	long disabled;
 	int cpu;
 
-	ftrace_graph_addr_finish(trace);
+	ftrace_graph_addr_finish(gops, trace);
 
 	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
 		trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
@@ -269,7 +269,7 @@ void trace_graph_return(struct ftrace_graph_ret *trace,
 static void trace_graph_thresh_return(struct ftrace_graph_ret *trace,
 				      struct fgraph_ops *gops)
 {
-	ftrace_graph_addr_finish(trace);
+	ftrace_graph_addr_finish(gops, trace);
 
 	if (trace_recursion_test(TRACE_GRAPH_NOTRACE_BIT)) {
 		trace_recursion_clear(TRACE_GRAPH_NOTRACE_BIT);
diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index 5478f4c4f708..fce064e20570 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -184,7 +184,7 @@ static int irqsoff_graph_entry(struct ftrace_graph_ent *trace,
 	unsigned int trace_ctx;
 	int ret;
 
-	if (ftrace_graph_ignore_func(trace))
+	if (ftrace_graph_ignore_func(gops, trace))
 		return 0;
 	/*
 	 * Do not trace a function if it's filtered by set_graph_notrace.
@@ -214,7 +214,7 @@ static void irqsoff_graph_return(struct ftrace_graph_ret *trace,
 	unsigned long flags;
 	unsigned int trace_ctx;
 
-	ftrace_graph_addr_finish(trace);
+	ftrace_graph_addr_finish(gops, trace);
 
 	if (!func_prolog_dec(tr, &data, &flags))
 		return;
diff --git a/kernel/trace/trace_sched_wakeup.c b/kernel/trace/trace_sched_wakeup.c
index 49bcc812652c..130ca7e7787e 100644
--- a/kernel/trace/trace_sched_wakeup.c
+++ b/kernel/trace/trace_sched_wakeup.c
@@ -120,7 +120,7 @@ static int wakeup_graph_entry(struct ftrace_graph_ent *trace,
 	unsigned int trace_ctx;
 	int ret = 0;
 
-	if (ftrace_graph_ignore_func(trace))
+	if (ftrace_graph_ignore_func(gops, trace))
 		return 0;
 	/*
 	 * Do not trace a function if it's filtered by set_graph_notrace.
@@ -149,7 +149,7 @@ static void wakeup_graph_return(struct ftrace_graph_ret *trace,
 	struct trace_array_cpu *data;
 	unsigned int trace_ctx;
 
-	ftrace_graph_addr_finish(trace);
+	ftrace_graph_addr_finish(gops, trace);
 
 	if (!func_prolog_preempt_disable(tr, &data, &trace_ctx))
 		return;


  parent reply	other threads:[~2023-11-08 14:27 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-08 14:24 [RFC PATCH v2 00/31] tracing: fprobe: function_graph: Multi-function graph and fprobe on fgraph Masami Hiramatsu (Google)
2023-11-08 14:24 ` [RFC PATCH v2 01/31] tracing: Add a comment about ftrace_regs definition Masami Hiramatsu (Google)
2023-11-08 23:14   ` Masami Hiramatsu
2023-11-10 11:11     ` Mark Rutland
2023-11-11  2:24       ` Masami Hiramatsu
2023-11-08 14:24 ` [RFC PATCH v2 02/31] x86: tracing: Add ftrace_regs definition in the header Masami Hiramatsu (Google)
2023-11-08 14:24 ` [RFC PATCH v2 03/31] seq_buf: Export seq_buf_puts() Masami Hiramatsu (Google)
2023-11-08 14:25 ` [RFC PATCH v2 04/31] function_graph: Convert ret_stack to a series of longs Masami Hiramatsu (Google)
2023-11-08 14:25 ` [RFC PATCH v2 05/31] fgraph: Use BUILD_BUG_ON() to make sure we have structures divisible by long Masami Hiramatsu (Google)
2023-11-08 14:25 ` [RFC PATCH v2 06/31] function_graph: Add an array structure that will allow multiple callbacks Masami Hiramatsu (Google)
2023-11-08 14:25 ` [RFC PATCH v2 07/31] function_graph: Allow multiple users to attach to function graph Masami Hiramatsu (Google)
2023-11-08 14:25 ` [RFC PATCH v2 08/31] function_graph: Remove logic around ftrace_graph_entry and return Masami Hiramatsu (Google)
2023-11-08 14:26 ` [RFC PATCH v2 09/31] ftrace/function_graph: Pass fgraph_ops to function graph callbacks Masami Hiramatsu (Google)
2023-11-08 14:26 ` [RFC PATCH v2 10/31] ftrace: Allow function_graph tracer to be enabled in instances Masami Hiramatsu (Google)
2023-11-08 14:26 ` [RFC PATCH v2 11/31] ftrace: Allow ftrace startup flags exist without dynamic ftrace Masami Hiramatsu (Google)
2023-11-08 14:26 ` [RFC PATCH v2 12/31] function_graph: Have the instances use their own ftrace_ops for filtering Masami Hiramatsu (Google)
2023-11-10  1:51   ` Masami Hiramatsu
2023-11-10  2:18     ` Steven Rostedt
2023-11-10  3:09       ` Masami Hiramatsu
2023-11-08 14:26 ` [RFC PATCH v2 13/31] function_graph: Add "task variables" per task for fgraph_ops Masami Hiramatsu (Google)
2023-11-08 14:27 ` Masami Hiramatsu (Google) [this message]
2023-11-08 14:27 ` [RFC PATCH v2 15/31] function_graph: Move graph depth stored data to shadow stack global var Masami Hiramatsu (Google)
2023-11-08 14:27 ` [RFC PATCH v2 16/31] function_graph: Move graph notrace bit " Masami Hiramatsu (Google)
2023-11-08 14:27 ` [RFC PATCH v2 17/31] function_graph: Implement fgraph_reserve_data() and fgraph_retrieve_data() Masami Hiramatsu (Google)
2023-11-08 14:27 ` [RFC PATCH v2 18/31] function_graph: Add selftest for passing local variables Masami Hiramatsu (Google)
2023-11-08 14:28 ` [RFC PATCH v2 19/31] function_graph: Add a new entry handler with parent_ip and ftrace_regs Masami Hiramatsu (Google)
2023-11-08 14:28 ` [RFC PATCH v2 20/31] function_graph: Add a new exit " Masami Hiramatsu (Google)
2023-11-08 23:17   ` Masami Hiramatsu
2023-11-08 14:28 ` [RFC PATCH v2 21/31] x86/ftrace: Enable HAVE_FUNCTION_GRAPH_FREGS Masami Hiramatsu (Google)
2023-11-08 14:28 ` [RFC PATCH v2 22/31] fprobe: Use ftrace_regs in fprobe entry handler Masami Hiramatsu (Google)
2023-11-08 14:28 ` [RFC PATCH v2 23/31] fprobe: Use ftrace_regs in fprobe exit handler Masami Hiramatsu (Google)
2023-11-08 14:28 ` [RFC PATCH v2 24/31] tracing: Add ftrace_partial_regs() for converting ftrace_regs to pt_regs Masami Hiramatsu (Google)
2023-11-08 14:29 ` [RFC PATCH v2 25/31] tracing: Add ftrace_fill_perf_regs() for perf event Masami Hiramatsu (Google)
2023-11-08 14:29 ` [RFC PATCH v2 26/31] fprobe: Rewrite fprobe on function-graph tracer Masami Hiramatsu (Google)
2023-11-10  7:17   ` Masami Hiramatsu
2023-11-11  1:44     ` Steven Rostedt
2023-11-11  3:01       ` Masami Hiramatsu
2023-11-08 14:29 ` [RFC PATCH v2 27/31] tracing/fprobe: Remove nr_maxactive from fprobe Masami Hiramatsu (Google)
2023-11-08 14:29 ` [RFC PATCH v2 28/31] tracing/fprobe: Enable fprobe events with CONFIG_DYNAMIC_FTRACE_WITH_ARGS Masami Hiramatsu (Google)
2023-11-08 14:29 ` [RFC PATCH v2 29/31] bpf: Enable kprobe_multi feature if CONFIG_FPROBE is enabled Masami Hiramatsu (Google)
2023-11-08 14:30 ` [RFC PATCH v2 30/31] selftests: ftrace: Remove obsolate maxactive syntax check Masami Hiramatsu (Google)
2023-11-08 14:30 ` [RFC PATCH v2 31/31] Documentation: probes: Update fprobe on function-graph tracer Masami Hiramatsu (Google)

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