Merge tag 'perf_urgent_for_v6.2_rc2' of git://git.kernel.org/pub/scm/linux/kernel...

Pull perf fixes from Borislav Petkov:

 - Pass only an initialized perf event attribute to the LSM hook

 - Fix a use-after-free on the perf syscall's error path

 - A potential integer overflow fix in amd_core_pmu_init()

 - Fix the cgroup events tracking after the context handling rewrite

 - Return the proper value from the inherit_event() function on error

* tag 'perf_urgent_for_v6.2_rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Call LSM hook after copying perf_event_attr
  perf: Fix use-after-free in error path
  perf/x86/amd: fix potential integer overflow on shift of a int
  perf/core: Fix cgroup events tracking
  perf core: Return error pointer if inherit_event() fails to find pmu_ctx

diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c
index d6f3703..4386b10 100644 (file)
--- a/arch/x86/events/amd/core.c
+++ b/arch/x86/events/amd/core.c
@@ -1387,7 +1387,7 @@ static int __init amd_core_pmu_init(void)
                 * numbered counter following it.
                 */
                for (i = 0; i < x86_pmu.num_counters - 1; i += 2)
-                       even_ctr_mask |= 1 << i;
+                       even_ctr_mask |= BIT_ULL(i);
 
                pair_constraint = (struct event_constraint)
                                    __EVENT_CONSTRAINT(0, even_ctr_mask, 0,

diff --git a/kernel/events/core.c b/kernel/events/core.c
index eacc370..d56328e 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -380,7 +380,6 @@ enum event_type_t {
 
 /*
  * perf_sched_events : >0 events exist
- * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
  */
 
 static void perf_sched_delayed(struct work_struct *work);
@@ -389,7 +388,6 @@ static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
 static DEFINE_MUTEX(perf_sched_mutex);
 static atomic_t perf_sched_count;
 
-static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
 static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
 
 static atomic_t nr_mmap_events __read_mostly;
@@ -844,9 +842,16 @@ static void perf_cgroup_switch(struct task_struct *task)
        struct perf_cpu_context *cpuctx = this_cpu_ptr(&perf_cpu_context);
        struct perf_cgroup *cgrp;
 
-       cgrp = perf_cgroup_from_task(task, NULL);
+       /*
+        * cpuctx->cgrp is set when the first cgroup event enabled,
+        * and is cleared when the last cgroup event disabled.
+        */
+       if (READ_ONCE(cpuctx->cgrp) == NULL)
+               return;
 
        WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
+
+       cgrp = perf_cgroup_from_task(task, NULL);
        if (READ_ONCE(cpuctx->cgrp) == cgrp)
                return;
 
@@ -3631,8 +3636,7 @@ void __perf_event_task_sched_out(struct task_struct *task,
         * to check if we have to switch out PMU state.
         * cgroup event are system-wide mode only
         */
-       if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
-               perf_cgroup_switch(next);
+       perf_cgroup_switch(next);
 }
 
 static bool perf_less_group_idx(const void *l, const void *r)
@@ -4974,15 +4978,6 @@ static void unaccount_pmu_sb_event(struct perf_event *event)
                detach_sb_event(event);
 }
 
-static void unaccount_event_cpu(struct perf_event *event, int cpu)
-{
-       if (event->parent)
-               return;
-
-       if (is_cgroup_event(event))
-               atomic_dec(&per_cpu(perf_cgroup_events, cpu));
-}
-
 #ifdef CONFIG_NO_HZ_FULL
 static DEFINE_SPINLOCK(nr_freq_lock);
 #endif
@@ -5048,8 +5043,6 @@ static void unaccount_event(struct perf_event *event)
                        schedule_delayed_work(&perf_sched_work, HZ);
        }
 
-       unaccount_event_cpu(event, event->cpu);
-
        unaccount_pmu_sb_event(event);
 }
 
@@ -11679,15 +11672,6 @@ static void account_pmu_sb_event(struct perf_event *event)
                attach_sb_event(event);
 }
 
-static void account_event_cpu(struct perf_event *event, int cpu)
-{
-       if (event->parent)
-               return;
-
-       if (is_cgroup_event(event))
-               atomic_inc(&per_cpu(perf_cgroup_events, cpu));
-}
-
 /* Freq events need the tick to stay alive (see perf_event_task_tick). */
 static void account_freq_event_nohz(void)
 {
@@ -11775,8 +11759,6 @@ static void account_event(struct perf_event *event)
        }
 enabled:
 
-       account_event_cpu(event, event->cpu);
-
        account_pmu_sb_event(event);
 }
 
@@ -12339,12 +12321,12 @@ SYSCALL_DEFINE5(perf_event_open,
        if (flags & ~PERF_FLAG_ALL)
                return -EINVAL;
 
-       /* Do we allow access to perf_event_open(2) ? */
-       err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
+       err = perf_copy_attr(attr_uptr, &attr);
        if (err)
                return err;
 
-       err = perf_copy_attr(attr_uptr, &attr);
+       /* Do we allow access to perf_event_open(2) ? */
+       err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
        if (err)
                return err;
 
@@ -12689,7 +12671,8 @@ SYSCALL_DEFINE5(perf_event_open,
        return event_fd;
 
 err_context:
-       /* event->pmu_ctx freed by free_event() */
+       put_pmu_ctx(event->pmu_ctx);
+       event->pmu_ctx = NULL; /* _free_event() */
 err_locked:
        mutex_unlock(&ctx->mutex);
        perf_unpin_context(ctx);
@@ -12802,6 +12785,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
 
 err_pmu_ctx:
        put_pmu_ctx(pmu_ctx);
+       event->pmu_ctx = NULL; /* _free_event() */
 err_unlock:
        mutex_unlock(&ctx->mutex);
        perf_unpin_context(ctx);
@@ -12822,13 +12806,11 @@ static void __perf_pmu_remove(struct perf_event_context *ctx,
 
        perf_event_groups_for_cpu_pmu(event, groups, cpu, pmu) {
                perf_remove_from_context(event, 0);
-               unaccount_event_cpu(event, cpu);
                put_pmu_ctx(event->pmu_ctx);
                list_add(&event->migrate_entry, events);
 
                for_each_sibling_event(sibling, event) {
                        perf_remove_from_context(sibling, 0);
-                       unaccount_event_cpu(sibling, cpu);
                        put_pmu_ctx(sibling->pmu_ctx);
                        list_add(&sibling->migrate_entry, events);
                }
@@ -12847,7 +12829,6 @@ static void __perf_pmu_install_event(struct pmu *pmu,
 
        if (event->state >= PERF_EVENT_STATE_OFF)
                event->state = PERF_EVENT_STATE_INACTIVE;
-       account_event_cpu(event, cpu);
        perf_install_in_context(ctx, event, cpu);
 }
 
@@ -13231,7 +13212,7 @@ inherit_event(struct perf_event *parent_event,
        pmu_ctx = find_get_pmu_context(child_event->pmu, child_ctx, child_event);
        if (IS_ERR(pmu_ctx)) {
                free_event(child_event);
-               return NULL;
+               return ERR_CAST(pmu_ctx);
        }
        child_event->pmu_ctx = pmu_ctx;
 
@@ -13742,8 +13723,7 @@ static int __perf_cgroup_move(void *info)
        struct task_struct *task = info;
 
        preempt_disable();
-       if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
-               perf_cgroup_switch(task);
+       perf_cgroup_switch(task);
        preempt_enable();
 
        return 0;