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()
This commit is contained in:
Linus Torvalds
commit
7b367f5dba
9 changed files with 158 additions and 58 deletions
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@ -1999,6 +1999,77 @@ static inline int get_first_held_lock(struct task_struct *curr,
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return ++i;
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}
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/*
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* Returns the next chain_key iteration
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*/
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static u64 print_chain_key_iteration(int class_idx, u64 chain_key)
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{
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u64 new_chain_key = iterate_chain_key(chain_key, class_idx);
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printk(" class_idx:%d -> chain_key:%016Lx",
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class_idx,
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(unsigned long long)new_chain_key);
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return new_chain_key;
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}
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static void
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print_chain_keys_held_locks(struct task_struct *curr, struct held_lock *hlock_next)
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{
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struct held_lock *hlock;
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u64 chain_key = 0;
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int depth = curr->lockdep_depth;
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int i;
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printk("depth: %u\n", depth + 1);
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for (i = get_first_held_lock(curr, hlock_next); i < depth; i++) {
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hlock = curr->held_locks + i;
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chain_key = print_chain_key_iteration(hlock->class_idx, chain_key);
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print_lock(hlock);
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}
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print_chain_key_iteration(hlock_next->class_idx, chain_key);
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print_lock(hlock_next);
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}
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static void print_chain_keys_chain(struct lock_chain *chain)
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{
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int i;
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u64 chain_key = 0;
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int class_id;
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printk("depth: %u\n", chain->depth);
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for (i = 0; i < chain->depth; i++) {
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class_id = chain_hlocks[chain->base + i];
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chain_key = print_chain_key_iteration(class_id + 1, chain_key);
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print_lock_name(lock_classes + class_id);
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printk("\n");
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}
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}
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static void print_collision(struct task_struct *curr,
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struct held_lock *hlock_next,
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struct lock_chain *chain)
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{
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printk("\n");
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printk("======================\n");
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printk("[chain_key collision ]\n");
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print_kernel_ident();
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printk("----------------------\n");
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printk("%s/%d: ", current->comm, task_pid_nr(current));
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printk("Hash chain already cached but the contents don't match!\n");
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printk("Held locks:");
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print_chain_keys_held_locks(curr, hlock_next);
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printk("Locks in cached chain:");
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print_chain_keys_chain(chain);
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printk("\nstack backtrace:\n");
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dump_stack();
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}
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/*
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* Checks whether the chain and the current held locks are consistent
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* in depth and also in content. If they are not it most likely means
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@ -2014,14 +2085,18 @@ static int check_no_collision(struct task_struct *curr,
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i = get_first_held_lock(curr, hlock);
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if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1)))
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if (DEBUG_LOCKS_WARN_ON(chain->depth != curr->lockdep_depth - (i - 1))) {
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print_collision(curr, hlock, chain);
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return 0;
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}
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for (j = 0; j < chain->depth - 1; j++, i++) {
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id = curr->held_locks[i].class_idx - 1;
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if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id))
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if (DEBUG_LOCKS_WARN_ON(chain_hlocks[chain->base + j] != id)) {
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print_collision(curr, hlock, chain);
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return 0;
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}
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}
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#endif
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return 1;
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@ -321,6 +321,24 @@ static inline void init_hrtick(void)
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}
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#endif /* CONFIG_SCHED_HRTICK */
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/*
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* cmpxchg based fetch_or, macro so it works for different integer types
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*/
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#define fetch_or(ptr, mask) \
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({ \
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typeof(ptr) _ptr = (ptr); \
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typeof(mask) _mask = (mask); \
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typeof(*_ptr) _old, _val = *_ptr; \
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\
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for (;;) { \
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_old = cmpxchg(_ptr, _val, _val | _mask); \
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if (_old == _val) \
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break; \
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_val = _old; \
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} \
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_old; \
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})
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#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
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/*
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* Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
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@ -157,52 +157,50 @@ static void tick_sched_handle(struct tick_sched *ts, struct pt_regs *regs)
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cpumask_var_t tick_nohz_full_mask;
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cpumask_var_t housekeeping_mask;
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bool tick_nohz_full_running;
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static unsigned long tick_dep_mask;
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static atomic_t tick_dep_mask;
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static void trace_tick_dependency(unsigned long dep)
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static bool check_tick_dependency(atomic_t *dep)
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{
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if (dep & TICK_DEP_MASK_POSIX_TIMER) {
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int val = atomic_read(dep);
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if (val & TICK_DEP_MASK_POSIX_TIMER) {
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trace_tick_stop(0, TICK_DEP_MASK_POSIX_TIMER);
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return;
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return true;
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}
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if (dep & TICK_DEP_MASK_PERF_EVENTS) {
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if (val & TICK_DEP_MASK_PERF_EVENTS) {
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trace_tick_stop(0, TICK_DEP_MASK_PERF_EVENTS);
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return;
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return true;
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}
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if (dep & TICK_DEP_MASK_SCHED) {
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if (val & TICK_DEP_MASK_SCHED) {
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trace_tick_stop(0, TICK_DEP_MASK_SCHED);
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return;
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return true;
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}
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if (dep & TICK_DEP_MASK_CLOCK_UNSTABLE)
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if (val & TICK_DEP_MASK_CLOCK_UNSTABLE) {
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trace_tick_stop(0, TICK_DEP_MASK_CLOCK_UNSTABLE);
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return true;
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}
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return false;
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}
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static bool can_stop_full_tick(struct tick_sched *ts)
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{
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WARN_ON_ONCE(!irqs_disabled());
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if (tick_dep_mask) {
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trace_tick_dependency(tick_dep_mask);
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if (check_tick_dependency(&tick_dep_mask))
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return false;
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}
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if (ts->tick_dep_mask) {
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trace_tick_dependency(ts->tick_dep_mask);
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if (check_tick_dependency(&ts->tick_dep_mask))
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return false;
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}
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if (current->tick_dep_mask) {
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trace_tick_dependency(current->tick_dep_mask);
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if (check_tick_dependency(¤t->tick_dep_mask))
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return false;
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}
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if (current->signal->tick_dep_mask) {
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trace_tick_dependency(current->signal->tick_dep_mask);
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if (check_tick_dependency(¤t->signal->tick_dep_mask))
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return false;
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}
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return true;
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}
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@ -259,12 +257,12 @@ static void tick_nohz_full_kick_all(void)
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preempt_enable();
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}
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static void tick_nohz_dep_set_all(unsigned long *dep,
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static void tick_nohz_dep_set_all(atomic_t *dep,
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enum tick_dep_bits bit)
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{
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unsigned long prev;
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int prev;
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prev = fetch_or(dep, BIT_MASK(bit));
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prev = atomic_fetch_or(dep, BIT(bit));
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if (!prev)
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tick_nohz_full_kick_all();
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}
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@ -280,7 +278,7 @@ void tick_nohz_dep_set(enum tick_dep_bits bit)
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void tick_nohz_dep_clear(enum tick_dep_bits bit)
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{
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clear_bit(bit, &tick_dep_mask);
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atomic_andnot(BIT(bit), &tick_dep_mask);
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}
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/*
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@ -289,12 +287,12 @@ void tick_nohz_dep_clear(enum tick_dep_bits bit)
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*/
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void tick_nohz_dep_set_cpu(int cpu, enum tick_dep_bits bit)
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{
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unsigned long prev;
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int prev;
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struct tick_sched *ts;
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ts = per_cpu_ptr(&tick_cpu_sched, cpu);
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prev = fetch_or(&ts->tick_dep_mask, BIT_MASK(bit));
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prev = atomic_fetch_or(&ts->tick_dep_mask, BIT(bit));
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if (!prev) {
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preempt_disable();
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/* Perf needs local kick that is NMI safe */
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@ -313,7 +311,7 @@ void tick_nohz_dep_clear_cpu(int cpu, enum tick_dep_bits bit)
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{
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struct tick_sched *ts = per_cpu_ptr(&tick_cpu_sched, cpu);
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clear_bit(bit, &ts->tick_dep_mask);
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atomic_andnot(BIT(bit), &ts->tick_dep_mask);
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}
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/*
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@ -331,7 +329,7 @@ void tick_nohz_dep_set_task(struct task_struct *tsk, enum tick_dep_bits bit)
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void tick_nohz_dep_clear_task(struct task_struct *tsk, enum tick_dep_bits bit)
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{
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clear_bit(bit, &tsk->tick_dep_mask);
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atomic_andnot(BIT(bit), &tsk->tick_dep_mask);
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}
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/*
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@ -345,7 +343,7 @@ void tick_nohz_dep_set_signal(struct signal_struct *sig, enum tick_dep_bits bit)
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void tick_nohz_dep_clear_signal(struct signal_struct *sig, enum tick_dep_bits bit)
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{
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clear_bit(bit, &sig->tick_dep_mask);
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atomic_andnot(BIT(bit), &sig->tick_dep_mask);
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}
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/*
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@ -366,7 +364,8 @@ void __tick_nohz_task_switch(void)
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ts = this_cpu_ptr(&tick_cpu_sched);
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if (ts->tick_stopped) {
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if (current->tick_dep_mask || current->signal->tick_dep_mask)
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if (atomic_read(¤t->tick_dep_mask) ||
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atomic_read(¤t->signal->tick_dep_mask))
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tick_nohz_full_kick();
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}
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out:
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@ -60,7 +60,7 @@ struct tick_sched {
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u64 next_timer;
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ktime_t idle_expires;
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int do_timer_last;
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unsigned long tick_dep_mask;
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atomic_t tick_dep_mask;
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};
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extern struct tick_sched *tick_get_tick_sched(int cpu);
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