[PATCH v3 03/11] perf: Support only inheriting events if cloned with CLONE_THREAD
STALE2013d
From: Marco Elver <elver@google.com>
Date: 2021-03-24 11:26:10
Also in:
linux-fsdevel, linux-kselftest, lkml
Subsystem:
exec & binfmt api, elf, memory management - core, performance events subsystem, scheduler, the rest · Maintainers:
Kees Cook, Andrew Morton, David Hildenbrand, Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Juri Lelli, Vincent Guittot, Linus Torvalds
Revision v3 of 4 in this series.
Revisions (4)
- rfc [diff vs current]
- v2 [diff vs current]
- v3 current
- v4 [diff vs current]
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/ (local) 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