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From: Marco Elver <elver@google.com>
To: elver@google.com, peterz@infradead.org,
	alexander.shishkin@linux.intel.com, acme@kernel.org,
	mingo@redhat.com, jolsa@redhat.com, mark.rutland@arm.com,
	namhyung@kernel.org, tglx@linutronix.de
Cc: glider@google.com, viro@zeniv.linux.org.uk, arnd@arndb.de,
	christian@brauner.io, dvyukov@google.com, jannh@google.com,
	axboe@kernel.dk, mascasa@google.com, pcc@google.com,
	irogers@google.com, kasan-dev@googlegroups.com,
	linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, x86@kernel.org,
	linux-kselftest@vger.kernel.org
Subject: [PATCH v3 03/11] perf: Support only inheriting events if cloned with CLONE_THREAD
Date: Wed, 24 Mar 2021 12:24:55 +0100	[thread overview]
Message-ID: <20210324112503.623833-4-elver@google.com> (raw)
In-Reply-To: <20210324112503.623833-1-elver@google.com>

Adds bit perf_event_attr::inherit_thread, to restricting inheriting
events only if the child was cloned with CLONE_THREAD.

This option supports the case where an event is supposed to be
process-wide only (including subthreads), but should not propagate
beyond the current process's shared environment.

Link: https://lore.kernel.org/lkml/YBvj6eJR%2FDY2TsEB@hirez.programming.kicks-ass.net/
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Marco Elver <elver@google.com>
---
v2:
* Add patch to series.
---
 include/linux/perf_event.h      |  5 +++--
 include/uapi/linux/perf_event.h |  3 ++-
 kernel/events/core.c            | 21 ++++++++++++++-------
 kernel/fork.c                   |  2 +-
 4 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 3d478abf411c..1660039199b2 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -958,7 +958,7 @@ extern void __perf_event_task_sched_in(struct task_struct *prev,
 				       struct task_struct *task);
 extern void __perf_event_task_sched_out(struct task_struct *prev,
 					struct task_struct *next);
-extern int perf_event_init_task(struct task_struct *child);
+extern int perf_event_init_task(struct task_struct *child, u64 clone_flags);
 extern void perf_event_exit_task(struct task_struct *child);
 extern void perf_event_free_task(struct task_struct *task);
 extern void perf_event_delayed_put(struct task_struct *task);
@@ -1449,7 +1449,8 @@ perf_event_task_sched_in(struct task_struct *prev,
 static inline void
 perf_event_task_sched_out(struct task_struct *prev,
 			  struct task_struct *next)			{ }
-static inline int perf_event_init_task(struct task_struct *child)	{ return 0; }
+static inline int perf_event_init_task(struct task_struct *child,
+				       u64 clone_flags)			{ return 0; }
 static inline void perf_event_exit_task(struct task_struct *child)	{ }
 static inline void perf_event_free_task(struct task_struct *task)	{ }
 static inline void perf_event_delayed_put(struct task_struct *task)	{ }
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index ad15e40d7f5d..813efb65fea8 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -389,7 +389,8 @@ struct perf_event_attr {
 				cgroup         :  1, /* include cgroup events */
 				text_poke      :  1, /* include text poke events */
 				build_id       :  1, /* use build id in mmap2 events */
-				__reserved_1   : 29;
+				inherit_thread :  1, /* children only inherit if cloned with CLONE_THREAD */
+				__reserved_1   : 28;
 
 	union {
 		__u32		wakeup_events;	  /* wakeup every n events */
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 37d106837962..224cbcf6125a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -11649,6 +11649,9 @@ static int perf_copy_attr(struct perf_event_attr __user *uattr,
 	    (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
 		return -EINVAL;
 
+	if (!attr->inherit && attr->inherit_thread)
+		return -EINVAL;
+
 out:
 	return ret;
 
@@ -12869,12 +12872,13 @@ static int
 inherit_task_group(struct perf_event *event, struct task_struct *parent,
 		   struct perf_event_context *parent_ctx,
 		   struct task_struct *child, int ctxn,
-		   int *inherited_all)
+		   u64 clone_flags, int *inherited_all)
 {
 	int ret;
 	struct perf_event_context *child_ctx;
 
-	if (!event->attr.inherit) {
+	if (!event->attr.inherit ||
+	    (event->attr.inherit_thread && !(clone_flags & CLONE_THREAD))) {
 		*inherited_all = 0;
 		return 0;
 	}
@@ -12906,7 +12910,8 @@ inherit_task_group(struct perf_event *event, struct task_struct *parent,
 /*
  * Initialize the perf_event context in task_struct
  */
-static int perf_event_init_context(struct task_struct *child, int ctxn)
+static int perf_event_init_context(struct task_struct *child, int ctxn,
+				   u64 clone_flags)
 {
 	struct perf_event_context *child_ctx, *parent_ctx;
 	struct perf_event_context *cloned_ctx;
@@ -12946,7 +12951,8 @@ static int perf_event_init_context(struct task_struct *child, int ctxn)
 	 */
 	perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
 		ret = inherit_task_group(event, parent, parent_ctx,
-					 child, ctxn, &inherited_all);
+					 child, ctxn, clone_flags,
+					 &inherited_all);
 		if (ret)
 			goto out_unlock;
 	}
@@ -12962,7 +12968,8 @@ static int perf_event_init_context(struct task_struct *child, int ctxn)
 
 	perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
 		ret = inherit_task_group(event, parent, parent_ctx,
-					 child, ctxn, &inherited_all);
+					 child, ctxn, clone_flags,
+					 &inherited_all);
 		if (ret)
 			goto out_unlock;
 	}
@@ -13004,7 +13011,7 @@ static int perf_event_init_context(struct task_struct *child, int ctxn)
 /*
  * Initialize the perf_event context in task_struct
  */
-int perf_event_init_task(struct task_struct *child)
+int perf_event_init_task(struct task_struct *child, u64 clone_flags)
 {
 	int ctxn, ret;
 
@@ -13013,7 +13020,7 @@ int perf_event_init_task(struct task_struct *child)
 	INIT_LIST_HEAD(&child->perf_event_list);
 
 	for_each_task_context_nr(ctxn) {
-		ret = perf_event_init_context(child, ctxn);
+		ret = perf_event_init_context(child, ctxn, clone_flags);
 		if (ret) {
 			perf_event_free_task(child);
 			return ret;
diff --git a/kernel/fork.c b/kernel/fork.c
index 54cc905e5fe0..aeccd7f46ce3 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2078,7 +2078,7 @@ static __latent_entropy struct task_struct *copy_process(
 	if (retval)
 		goto bad_fork_cleanup_policy;
 
-	retval = perf_event_init_task(p);
+	retval = perf_event_init_task(p, clone_flags);
 	if (retval)
 		goto bad_fork_cleanup_policy;
 	retval = audit_alloc(p);
-- 
2.31.0.291.g576ba9dcdaf-goog


  parent reply	other threads:[~2021-03-24 11:26 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-24 11:24 [PATCH v3 00/11] Add support for synchronous signals on perf events Marco Elver
2021-03-24 11:24 ` [PATCH v3 01/11] perf: Rework perf_event_exit_event() Marco Elver
2021-03-25 10:17   ` Marco Elver
2021-03-25 16:17     ` Marco Elver
2021-03-25 19:10       ` Marco Elver
2021-03-29 11:50         ` Peter Zijlstra
2021-03-24 11:24 ` [PATCH v3 02/11] perf: Apply PERF_EVENT_IOC_MODIFY_ATTRIBUTES to children Marco Elver
2021-03-24 11:24 ` Marco Elver [this message]
2021-03-24 11:24 ` [PATCH v3 04/11] perf: Add support for event removal on exec Marco Elver
2021-03-24 11:24 ` [PATCH v3 05/11] signal: Introduce TRAP_PERF si_code and si_perf to siginfo Marco Elver
2021-03-24 11:24 ` [PATCH v3 06/11] perf: Add support for SIGTRAP on perf events Marco Elver
2021-03-25  8:14   ` Marco Elver
2021-03-29 12:07     ` Peter Zijlstra
2021-03-29 14:27       ` Oleg Nesterov
2021-03-29 14:32         ` Marco Elver
2021-03-30  7:04           ` Peter Zijlstra
2021-03-29 18:22         ` Marco Elver
2021-03-29 18:33           ` Oleg Nesterov
2021-03-31 12:32       ` Marco Elver
2021-03-31 14:51         ` Peter Zijlstra
2021-03-31 16:50           ` Marco Elver
2021-03-24 11:24 ` [PATCH v3 07/11] perf: Add breakpoint information to siginfo on SIGTRAP Marco Elver
2021-03-24 12:53   ` Peter Zijlstra
2021-03-24 13:01     ` Peter Zijlstra
2021-03-24 13:21       ` Peter Zijlstra
2021-03-24 13:43         ` Peter Zijlstra
2021-03-24 14:00           ` Peter Zijlstra
2021-03-24 14:05             ` Marco Elver
2021-03-24 14:12               ` Dmitry Vyukov
2021-03-24 14:15                 ` Dmitry Vyukov
2021-03-25  7:00                   ` Marco Elver
2021-03-25 14:18                 ` Ingo Molnar
2021-03-25 15:17                   ` Marco Elver
2021-03-25 15:35                     ` Ingo Molnar
2021-03-24 13:47         ` Marco Elver
2021-03-24 11:25 ` [PATCH v3 08/11] selftests/perf_events: Add kselftest for process-wide sigtrap handling Marco Elver
2021-03-24 11:25 ` [PATCH v3 09/11] selftests/perf_events: Add kselftest for remove_on_exec Marco Elver
2021-03-24 11:25 ` [PATCH v3 10/11] tools headers uapi: Sync tools/include/uapi/linux/perf_event.h Marco Elver
2021-03-24 11:25 ` [PATCH v3 11/11] perf test: Add basic stress test for sigtrap handling Marco Elver

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