Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core kernel fixes from Ingo Molnar:
 "This contains the nohz/atomic cleanup/fix for the fetch_or() ugliness
  you noted during the original nohz pull request, plus there's also
  misc fixes:

   - fix liblockdep build bug
   - fix uapi header build bug
   - print more lockdep hash collision info to help debug recent reports
     of hash collisions
   - update MAINTAINERS email address"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Update my email address
  locking/lockdep: Print chain_key collision information
  uapi/linux/stddef.h: Provide __always_inline to userspace headers
  tools/lib/lockdep: Fix unsupported 'basename -s' in run_tests.sh
  locking/atomic, sched: Unexport fetch_or()
  timers/nohz: Convert tick dependency mask to atomic_t
  locking/atomic: Introduce atomic_fetch_or()

9 files changed, 158 insertions, 58 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index fbd6f5288116..1c32f8a3d6c4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6403,7 +6403,7 @@ KPROBES
 M:      Ananth N Mavinakayanahalli <ananth@in.ibm.com>
 M:      Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
 M:      "David S. Miller" <davem@davemloft.net>
-M:      Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
+M:      Masami Hiramatsu <mhiramat@kernel.org>
 S:      Maintained
 F:      Documentation/kprobes.txt
 F:      include/linux/kprobes.h
diff --git a/include/linux/atomic.h b/include/linux/atomic.h
index df4f369254c0..506c3531832e 100644
--- a/include/linux/atomic.h
+++ b/include/linux/atomic.h
@@ -559,25 +559,25 @@ static inline int atomic_dec_if_positive(atomic_t *v)
 #endif
 
 /**
- * fetch_or - perform *ptr |= mask and return old value of *ptr
- * @ptr: pointer to value
- * @mask: mask to OR on the value
- *
- * cmpxchg based fetch_or, macro so it works for different integer types
+ * atomic_fetch_or - perform *p |= mask and return old value of *p
+ * @p: pointer to atomic_t
+ * @mask: mask to OR on the atomic_t
  */
-#ifndef fetch_or
-#define fetch_or(ptr, mask)                                             \
-({      typeof(*(ptr)) __old, __val = *(ptr);                           \
-        for (;;) {                                                      \
-                __old = cmpxchg((ptr), __val, __val | (mask));          \
-                if (__old == __val)                                     \
-                        break;                                          \
-                __val = __old;                                          \
-        }                                                               \
-        __old;                                                          \
-})
-#endif
+#ifndef atomic_fetch_or
+static inline int atomic_fetch_or(atomic_t *p, int mask)
+{
+        int old, val = atomic_read(p);
+
+        for (;;) {
+                old = atomic_cmpxchg(p, val, val | mask);
+                if (old == val)
+                        break;
+                val = old;
+        }
 
+        return old;
+}
+#endif
 
 #ifdef CONFIG_GENERIC_ATOMIC64
 #include <asm-generic/atomic64.h>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 60bba7e032dc..52c4847b05e2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -720,7 +720,7 @@ struct signal_struct {
         struct task_cputime cputime_expires;
 
 #ifdef CONFIG_NO_HZ_FULL
-        unsigned long tick_dep_mask;
+        atomic_t tick_dep_mask;
 #endif
 
         struct list_head cpu_timers[3];
@@ -1549,7 +1549,7 @@ struct task_struct {
 #endif
 
 #ifdef CONFIG_NO_HZ_FULL
-        unsigned long tick_dep_mask;
+        atomic_t tick_dep_mask;
 #endif
         unsigned long nvcsw, nivcsw; /* context switch counts */
         u64 start_time;         /* monotonic time in nsec */
diff --git a/include/uapi/linux/stddef.h b/include/uapi/linux/stddef.h
index aa9f10428743..621fa8ac4425 100644
--- a/include/uapi/linux/stddef.h
+++ b/include/uapi/linux/stddef.h
@@ -1 +1,5 @@
 #include <linux/compiler.h>
+
+#ifndef __always_inline
+#define __always_inline inline
+#endif
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;
 bool tick_nohz_full_running;
-static unsigned long tick_dep_mask;
+static atomic_t tick_dep_mask;
 
-static void trace_tick_dependency(unsigned long dep)
+static bool check_tick_dependency(atomic_t *dep)
 {
-        if (dep & TICK_DEP_MASK_POSIX_TIMER) {
+        int val = atomic_read(dep);
+
+        if (val & TICK_DEP_MASK_POSIX_TIMER) {
                 trace_tick_stop(0, TICK_DEP_MASK_POSIX_TIMER);
-                return;
+                return true;
         }
 
-        if (dep & TICK_DEP_MASK_PERF_EVENTS) {
+        if (val & TICK_DEP_MASK_PERF_EVENTS) {
                 trace_tick_stop(0, TICK_DEP_MASK_PERF_EVENTS);
-                return;
+                return true;
         }
 
-        if (dep & TICK_DEP_MASK_SCHED) {
+        if (val & TICK_DEP_MASK_SCHED) {
                 trace_tick_stop(0, TICK_DEP_MASK_SCHED);
-                return;
+                return true;
         }
 
-        if (dep & TICK_DEP_MASK_CLOCK_UNSTABLE)
+        if (val & TICK_DEP_MASK_CLOCK_UNSTABLE) {
                 trace_tick_stop(0, TICK_DEP_MASK_CLOCK_UNSTABLE);
+                return true;
+        }
+
+        return false;
 }
 
 static bool can_stop_full_tick(struct tick_sched *ts)
 {
         WARN_ON_ONCE(!irqs_disabled());
 
-        if (tick_dep_mask) {
-                trace_tick_dependency(tick_dep_mask);
+        if (check_tick_dependency(&tick_dep_mask))
                 return false;
-        }
 
-        if (ts->tick_dep_mask) {
-                trace_tick_dependency(ts->tick_dep_mask);
+        if (check_tick_dependency(&ts->tick_dep_mask))
                 return false;
-        }
 
-        if (current->tick_dep_mask) {
-                trace_tick_dependency(current->tick_dep_mask);
+        if (check_tick_dependency(&current->tick_dep_mask))
                 return false;
-        }
 
-        if (current->signal->tick_dep_mask) {
-                trace_tick_dependency(current->signal->tick_dep_mask);
+        if (check_tick_dependency(&current->signal->tick_dep_mask))
                 return false;
-        }
 
         return true;
 }
@@ -259,12 +257,12 @@ static void tick_nohz_full_kick_all(void)
         preempt_enable();
 }
 
-static void tick_nohz_dep_set_all(unsigned long *dep,
+static void tick_nohz_dep_set_all(atomic_t *dep,
                                   enum tick_dep_bits bit)
 {
-        unsigned long prev;
+        int prev;
 
-        prev = fetch_or(dep, BIT_MASK(bit));
+        prev = atomic_fetch_or(dep, BIT(bit));
         if (!prev)
                 tick_nohz_full_kick_all();
 }
@@ -280,7 +278,7 @@ void tick_nohz_dep_set(enum tick_dep_bits bit)
 
 void tick_nohz_dep_clear(enum tick_dep_bits bit)
 {
-        clear_bit(bit, &tick_dep_mask);
+        atomic_andnot(BIT(bit), &tick_dep_mask);
 }
 
 /*
@@ -289,12 +287,12 @@ void tick_nohz_dep_clear(enum tick_dep_bits bit)
  */
 void tick_nohz_dep_set_cpu(int cpu, enum tick_dep_bits bit)
 {
-        unsigned long prev;
+        int prev;
         struct tick_sched *ts;
 
         ts = per_cpu_ptr(&tick_cpu_sched, cpu);
 
-        prev = fetch_or(&ts->tick_dep_mask, BIT_MASK(bit));
+        prev = atomic_fetch_or(&ts->tick_dep_mask, BIT(bit));
         if (!prev) {
                 preempt_disable();
                 /* Perf needs local kick that is NMI safe */
@@ -313,7 +311,7 @@ void tick_nohz_dep_clear_cpu(int cpu, enum tick_dep_bits bit)
 {
         struct tick_sched *ts = per_cpu_ptr(&tick_cpu_sched, cpu);
 
-        clear_bit(bit, &ts->tick_dep_mask);
+        atomic_andnot(BIT(bit), &ts->tick_dep_mask);
 }
 
 /*
@@ -331,7 +329,7 @@ void tick_nohz_dep_set_task(struct task_struct *tsk, enum tick_dep_bits bit)
 
 void tick_nohz_dep_clear_task(struct task_struct *tsk, enum tick_dep_bits bit)
 {
-        clear_bit(bit, &tsk->tick_dep_mask);
+        atomic_andnot(BIT(bit), &tsk->tick_dep_mask);
 }
 
 /*
@@ -345,7 +343,7 @@ void tick_nohz_dep_set_signal(struct signal_struct *sig, enum tick_dep_bits bit)
 
 void tick_nohz_dep_clear_signal(struct signal_struct *sig, enum tick_dep_bits bit)
 {
-        clear_bit(bit, &sig->tick_dep_mask);
+        atomic_andnot(BIT(bit), &sig->tick_dep_mask);
 }
 
 /*
@@ -366,7 +364,8 @@ void __tick_nohz_task_switch(void)
         ts = this_cpu_ptr(&tick_cpu_sched);
 
         if (ts->tick_stopped) {
-                if (current->tick_dep_mask || current->signal->tick_dep_mask)
+                if (atomic_read(&current->tick_dep_mask) ||
+                    atomic_read(&current->signal->tick_dep_mask))
                         tick_nohz_full_kick();
         }
 out:
diff --git a/kernel/time/tick-sched.h b/kernel/time/tick-sched.h
index eb4e32566a83..bf38226e5c17 100644
--- a/kernel/time/tick-sched.h
+++ b/kernel/time/tick-sched.h
@@ -60,7 +60,7 @@ struct tick_sched {
         u64                             next_timer;
         ktime_t                         idle_expires;
         int                             do_timer_last;
-        unsigned long                   tick_dep_mask;
+        atomic_t                        tick_dep_mask;
 };
 
 extern struct tick_sched *tick_get_tick_sched(int cpu);
diff --git a/tools/lib/lockdep/run_tests.sh b/tools/lib/lockdep/run_tests.sh
index 5334ad9d39b7..1069d96248c1 100755
--- a/tools/lib/lockdep/run_tests.sh
+++ b/tools/lib/lockdep/run_tests.sh
@@ -3,7 +3,7 @@
 make &> /dev/null
 
 for i in `ls tests/*.c`; do
-        testname=$(basename -s .c "$i")
+        testname=$(basename "$i" .c)
         gcc -o tests/$testname -pthread -lpthread $i liblockdep.a -Iinclude -D__USE_LIBLOCKDEP &> /dev/null
         echo -ne "$testname... "
         if [ $(timeout 1 ./tests/$testname | wc -l) -gt 0 ]; then
@@ -11,11 +11,13 @@ for i in `ls tests/*.c`; do
         else
                 echo "FAILED!"
         fi
-        rm tests/$testname
+        if [ -f "tests/$testname" ]; then
+                rm tests/$testname
+        fi
 done
 
 for i in `ls tests/*.c`; do
-        testname=$(basename -s .c "$i")
+        testname=$(basename "$i" .c)
         gcc -o tests/$testname -pthread -lpthread -Iinclude $i &> /dev/null
         echo -ne "(PRELOAD) $testname... "
         if [ $(timeout 1 ./lockdep ./tests/$testname | wc -l) -gt 0 ]; then
@@ -23,5 +25,7 @@ for i in `ls tests/*.c`; do
         else
                 echo "FAILED!"
         fi
-        rm tests/$testname
+        if [ -f "tests/$testname" ]; then
+                rm tests/$testname
+        fi
 done