6 files changed, 143 insertions, 38 deletions

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 2a2efe1bc76c..adc5e4bd74f8 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -137,11 +137,13 @@ static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
                    "map_type:\t%u\n"
                    "key_size:\t%u\n"
                    "value_size:\t%u\n"
-                   "max_entries:\t%u\n",
+                   "max_entries:\t%u\n"
+                   "map_flags:\t%#x\n",
                    map->map_type,
                    map->key_size,
                    map->value_size,
-                   map->max_entries);
+                   map->max_entries,
+                   map->map_flags);
 }
 #endif
 
diff --git a/kernel/events/core.c b/kernel/events/core.c
index de24fbce5277..52bedc5a5aaa 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -2417,14 +2417,24 @@ static void ctx_sched_out(struct perf_event_context *ctx,
                         cpuctx->task_ctx = NULL;
         }
 
-        is_active ^= ctx->is_active; /* changed bits */
-
+        /*
+         * Always update time if it was set; not only when it changes.
+         * Otherwise we can 'forget' to update time for any but the last
+         * context we sched out. For example:
+         *
+         *   ctx_sched_out(.event_type = EVENT_FLEXIBLE)
+         *   ctx_sched_out(.event_type = EVENT_PINNED)
+         *
+         * would only update time for the pinned events.
+         */
         if (is_active & EVENT_TIME) {
                 /* update (and stop) ctx time */
                 update_context_time(ctx);
                 update_cgrp_time_from_cpuctx(cpuctx);
         }
 
+        is_active ^= ctx->is_active; /* changed bits */
+
         if (!ctx->nr_active || !(is_active & EVENT_ALL))
                 return;
 
@@ -8532,6 +8542,7 @@ SYSCALL_DEFINE5(perf_event_open,
                                         f_flags);
         if (IS_ERR(event_file)) {
                 err = PTR_ERR(event_file);
+                event_file = NULL;
                 goto err_context;
         }
 
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 53ab2f85d77e..2324ba5310db 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2000,6 +2000,77 @@ static inline int get_first_held_lock(struct task_struct *curr,
 }
 
 /*
+ * Returns the next chain_key iteration
+ */
+static u64 print_chain_key_iteration(int class_idx, u64 chain_key)
+{
+        u64 new_chain_key = iterate_chain_key(chain_key, class_idx);
+
+        printk(" class_idx:%d -> chain_key:%016Lx",
+                class_idx,
+                (unsigned long long)new_chain_key);
+        return new_chain_key;
+}
+
+static void
+print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next)
+{
+        struct held_lock *hlock;
+        u64 chain_key = 0;
+        int depth = curr->lockdep_depth;
+        int i;
+
+        printk("depth: %u\n", depth + 1);
+        for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) {
+                hlock = curr->held_locks + i;
+                chain_key = print_chain_key_iteration(hlock->class_idx, chain_key);
+
+                print_lock(hlock);
+        }
+
+        print_chain_key_iteration(hlock_next->class_idx, chain_key);
+        print_lock(hlock_next);
+}
+
+static void print_chain_keys_chain(struct lock_chain *chain)
+{
+        int i;
+        u64 chain_key = 0;
+        int class_id;
+
+        printk("depth: %u\n", chain->depth);
+        for (i = 0; i < chain->depth; i++) {
+                class_id = chain_hlocks[chain->base + i];
+                chain_key = print_chain_key_iteration(class_id + 1, chain_key);
+
+                print_lock_name(lock_classes + class_id);
+                printk("\n");
+        }
+}
+
+static void print_collision(struct task_struct *curr,
+                        struct held_lock *hlock_next,
+                        struct lock_chain *chain)
+{
+        printk("\n");
+        printk("======================\n");
+        printk("[chain_key collision ]\n");
+        print_kernel_ident();
+        printk("----------------------\n");
+        printk("%s/%d: ", current->comm, task_pid_nr(current));
+        printk("Hash chain already cached but the contents don't match!\n");
+
+        printk("Held locks:");
+        print_chain_keys_held_locks(curr, hlock_next);
+
+        printk("Locks in cached chain:");
+        print_chain_keys_chain(chain);
+
+        printk("\nstack backtrace:\n");
+        dump_stack();
+}
+
+/*
  * Checks whether the chain and the current held locks are consistent
  * in depth and also in content. If they are not it most likely means
  * that there was a collision during the calculation of the chain_key.
@@ -2014,14 +2085,18 @@ static int check_no_collision(struct task_struct *curr,
 
         i = get_first_held_lock(curr, hlock);
 
-        if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1)))
+        if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) {
+                print_collision(curr, hlock, chain);
                 return 0;
+        }
 
         for (j = 0; j < chain->depth - 1; j++, i++) {
                 id = curr->held_locks[i].class_idx - 1;
 
-                if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id))
+                if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) {
+                        print_collision(curr, hlock, chain);
                         return 0;
+                }
         }
 #endif
         return 1;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d8465eeab8b3..8b489fcac37b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -321,6 +321,24 @@ static inline void init_hrtick(void)
 }
 #endif  /* CONFIG_SCHED_HRTICK */
 
+/*
+ * cmpxchg based fetch_or, macro so it works for different integer types
+ */
+#define fetch_or(ptr, mask)                                             \
+        ({                                                              \
+                typeof(ptr) _ptr = (ptr);                               \
+                typeof(mask) _mask = (mask);                            \
+                typeof(*_ptr) _old, _val = *_ptr;                       \
+                                                                        \
+                for (;;) {                                              \
+                        _old = cmpxchg(_ptr, _val, _val | _mask);       \
+                        if (_old == _val)                               \
+                                break;                                  \
+                        _val = _old;                                    \
+                }                                                       \
+        _old;                                                           \
+})
+
 #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
 /*
  * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 084b79f5917e..58e3310c9b21 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -157,52 +157,50 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
 cpumask_var_t tick_nohz_full_mask;
 cpumask_var_t housekeeping_mask;