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![Andrew Morton](/assets/img/avatar_default.png)
When a spinlock lockup occurs, arrange for the NMI code to emit an all-cpu backtrace, so we get to see which CPU is holding the lock, and where. Cc: Andi Kleen <ak@muc.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Badari Pulavarty <pbadari@us.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Andi Kleen <ak@suse.de>
297 lines
6.8 KiB
C
297 lines
6.8 KiB
C
/*
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* Copyright 2005, Red Hat, Inc., Ingo Molnar
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* Released under the General Public License (GPL).
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*
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* This file contains the spinlock/rwlock implementations for
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* DEBUG_SPINLOCK.
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*/
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#include <linux/spinlock.h>
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#include <linux/nmi.h>
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#include <linux/interrupt.h>
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#include <linux/debug_locks.h>
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#include <linux/delay.h>
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#include <linux/module.h>
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void __spin_lock_init(spinlock_t *lock, const char *name,
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struct lock_class_key *key)
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{
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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/*
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* Make sure we are not reinitializing a held lock:
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*/
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debug_check_no_locks_freed((void *)lock, sizeof(*lock));
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lockdep_init_map(&lock->dep_map, name, key, 0);
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#endif
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lock->raw_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
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lock->magic = SPINLOCK_MAGIC;
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lock->owner = SPINLOCK_OWNER_INIT;
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lock->owner_cpu = -1;
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}
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EXPORT_SYMBOL(__spin_lock_init);
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void __rwlock_init(rwlock_t *lock, const char *name,
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struct lock_class_key *key)
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{
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#ifdef CONFIG_DEBUG_LOCK_ALLOC
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/*
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* Make sure we are not reinitializing a held lock:
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*/
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debug_check_no_locks_freed((void *)lock, sizeof(*lock));
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lockdep_init_map(&lock->dep_map, name, key, 0);
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#endif
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lock->raw_lock = (raw_rwlock_t) __RAW_RW_LOCK_UNLOCKED;
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lock->magic = RWLOCK_MAGIC;
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lock->owner = SPINLOCK_OWNER_INIT;
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lock->owner_cpu = -1;
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}
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EXPORT_SYMBOL(__rwlock_init);
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static void spin_bug(spinlock_t *lock, const char *msg)
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{
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struct task_struct *owner = NULL;
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if (!debug_locks_off())
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return;
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if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
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owner = lock->owner;
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printk(KERN_EMERG "BUG: spinlock %s on CPU#%d, %s/%d\n",
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msg, raw_smp_processor_id(),
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current->comm, current->pid);
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printk(KERN_EMERG " lock: %p, .magic: %08x, .owner: %s/%d, "
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".owner_cpu: %d\n",
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lock, lock->magic,
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owner ? owner->comm : "<none>",
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owner ? owner->pid : -1,
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lock->owner_cpu);
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dump_stack();
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}
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#define SPIN_BUG_ON(cond, lock, msg) if (unlikely(cond)) spin_bug(lock, msg)
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static inline void
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debug_spin_lock_before(spinlock_t *lock)
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{
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SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
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SPIN_BUG_ON(lock->owner == current, lock, "recursion");
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SPIN_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
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lock, "cpu recursion");
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}
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static inline void debug_spin_lock_after(spinlock_t *lock)
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{
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lock->owner_cpu = raw_smp_processor_id();
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lock->owner = current;
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}
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static inline void debug_spin_unlock(spinlock_t *lock)
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{
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SPIN_BUG_ON(lock->magic != SPINLOCK_MAGIC, lock, "bad magic");
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SPIN_BUG_ON(!spin_is_locked(lock), lock, "already unlocked");
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SPIN_BUG_ON(lock->owner != current, lock, "wrong owner");
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SPIN_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
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lock, "wrong CPU");
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lock->owner = SPINLOCK_OWNER_INIT;
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lock->owner_cpu = -1;
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}
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static void __spin_lock_debug(spinlock_t *lock)
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{
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u64 i;
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u64 loops = loops_per_jiffy * HZ;
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int print_once = 1;
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for (;;) {
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for (i = 0; i < loops; i++) {
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if (__raw_spin_trylock(&lock->raw_lock))
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return;
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__delay(1);
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}
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/* lockup suspected: */
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if (print_once) {
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print_once = 0;
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printk(KERN_EMERG "BUG: spinlock lockup on CPU#%d, "
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"%s/%d, %p\n",
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raw_smp_processor_id(), current->comm,
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current->pid, lock);
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dump_stack();
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#ifdef CONFIG_SMP
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trigger_all_cpu_backtrace();
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#endif
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}
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}
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}
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void _raw_spin_lock(spinlock_t *lock)
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{
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debug_spin_lock_before(lock);
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if (unlikely(!__raw_spin_trylock(&lock->raw_lock)))
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__spin_lock_debug(lock);
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debug_spin_lock_after(lock);
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}
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int _raw_spin_trylock(spinlock_t *lock)
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{
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int ret = __raw_spin_trylock(&lock->raw_lock);
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if (ret)
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debug_spin_lock_after(lock);
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#ifndef CONFIG_SMP
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/*
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* Must not happen on UP:
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*/
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SPIN_BUG_ON(!ret, lock, "trylock failure on UP");
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#endif
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return ret;
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}
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void _raw_spin_unlock(spinlock_t *lock)
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{
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debug_spin_unlock(lock);
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__raw_spin_unlock(&lock->raw_lock);
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}
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static void rwlock_bug(rwlock_t *lock, const char *msg)
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{
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if (!debug_locks_off())
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return;
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printk(KERN_EMERG "BUG: rwlock %s on CPU#%d, %s/%d, %p\n",
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msg, raw_smp_processor_id(), current->comm,
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current->pid, lock);
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dump_stack();
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}
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#define RWLOCK_BUG_ON(cond, lock, msg) if (unlikely(cond)) rwlock_bug(lock, msg)
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#if 0 /* __write_lock_debug() can lock up - maybe this can too? */
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static void __read_lock_debug(rwlock_t *lock)
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{
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u64 i;
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u64 loops = loops_per_jiffy * HZ;
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int print_once = 1;
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for (;;) {
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for (i = 0; i < loops; i++) {
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if (__raw_read_trylock(&lock->raw_lock))
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return;
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__delay(1);
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}
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/* lockup suspected: */
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if (print_once) {
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print_once = 0;
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printk(KERN_EMERG "BUG: read-lock lockup on CPU#%d, "
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"%s/%d, %p\n",
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raw_smp_processor_id(), current->comm,
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current->pid, lock);
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dump_stack();
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}
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}
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}
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#endif
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void _raw_read_lock(rwlock_t *lock)
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{
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RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
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__raw_read_lock(&lock->raw_lock);
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}
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int _raw_read_trylock(rwlock_t *lock)
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{
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int ret = __raw_read_trylock(&lock->raw_lock);
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#ifndef CONFIG_SMP
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/*
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* Must not happen on UP:
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*/
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RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
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#endif
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return ret;
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}
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void _raw_read_unlock(rwlock_t *lock)
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{
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RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
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__raw_read_unlock(&lock->raw_lock);
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}
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static inline void debug_write_lock_before(rwlock_t *lock)
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{
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RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
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RWLOCK_BUG_ON(lock->owner == current, lock, "recursion");
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RWLOCK_BUG_ON(lock->owner_cpu == raw_smp_processor_id(),
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lock, "cpu recursion");
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}
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static inline void debug_write_lock_after(rwlock_t *lock)
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{
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lock->owner_cpu = raw_smp_processor_id();
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lock->owner = current;
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}
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static inline void debug_write_unlock(rwlock_t *lock)
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{
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RWLOCK_BUG_ON(lock->magic != RWLOCK_MAGIC, lock, "bad magic");
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RWLOCK_BUG_ON(lock->owner != current, lock, "wrong owner");
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RWLOCK_BUG_ON(lock->owner_cpu != raw_smp_processor_id(),
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lock, "wrong CPU");
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lock->owner = SPINLOCK_OWNER_INIT;
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lock->owner_cpu = -1;
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}
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#if 0 /* This can cause lockups */
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static void __write_lock_debug(rwlock_t *lock)
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{
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u64 i;
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u64 loops = loops_per_jiffy * HZ;
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int print_once = 1;
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for (;;) {
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for (i = 0; i < loops; i++) {
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if (__raw_write_trylock(&lock->raw_lock))
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return;
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__delay(1);
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}
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/* lockup suspected: */
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if (print_once) {
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print_once = 0;
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printk(KERN_EMERG "BUG: write-lock lockup on CPU#%d, "
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"%s/%d, %p\n",
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raw_smp_processor_id(), current->comm,
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current->pid, lock);
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dump_stack();
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}
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}
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}
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#endif
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void _raw_write_lock(rwlock_t *lock)
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{
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debug_write_lock_before(lock);
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__raw_write_lock(&lock->raw_lock);
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debug_write_lock_after(lock);
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}
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int _raw_write_trylock(rwlock_t *lock)
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{
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int ret = __raw_write_trylock(&lock->raw_lock);
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if (ret)
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debug_write_lock_after(lock);
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#ifndef CONFIG_SMP
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/*
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* Must not happen on UP:
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*/
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RWLOCK_BUG_ON(!ret, lock, "trylock failure on UP");
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#endif
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return ret;
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}
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void _raw_write_unlock(rwlock_t *lock)
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{
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debug_write_unlock(lock);
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__raw_write_unlock(&lock->raw_lock);
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}
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