lockdep: Check if nested lock is actually held
It is considered good form to lock the lock you claim to be nested in. Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> [ removed nest_lock arg to print_lock_nested_lock_not_held in favour of hlock->nest_lock, also renamed the lock arg to hlock since its a held_lock type ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/5051A9E7.5040501@canonical.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -2998,6 +2998,42 @@ EXPORT_SYMBOL_GPL(lockdep_init_map);
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struct lock_class_key __lockdep_no_validate__;
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struct lock_class_key __lockdep_no_validate__;
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static int
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print_lock_nested_lock_not_held(struct task_struct *curr,
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struct held_lock *hlock,
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unsigned long ip)
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{
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if (!debug_locks_off())
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return 0;
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if (debug_locks_silent)
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return 0;
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printk("\n");
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printk("==================================\n");
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printk("[ BUG: Nested lock was not taken ]\n");
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print_kernel_ident();
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printk("----------------------------------\n");
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printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
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print_lock(hlock);
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printk("\nbut this task is not holding:\n");
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printk("%s\n", hlock->nest_lock->name);
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printk("\nstack backtrace:\n");
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dump_stack();
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printk("\nother info that might help us debug this:\n");
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lockdep_print_held_locks(curr);
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printk("\nstack backtrace:\n");
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dump_stack();
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return 0;
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}
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static int __lock_is_held(struct lockdep_map *lock);
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/*
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/*
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* This gets called for every mutex_lock*()/spin_lock*() operation.
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* This gets called for every mutex_lock*()/spin_lock*() operation.
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* We maintain the dependency maps and validate the locking attempt:
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* We maintain the dependency maps and validate the locking attempt:
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@ -3139,6 +3175,9 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
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}
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}
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chain_key = iterate_chain_key(chain_key, id);
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chain_key = iterate_chain_key(chain_key, id);
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if (nest_lock && !__lock_is_held(nest_lock))
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return print_lock_nested_lock_not_held(curr, hlock, ip);
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if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
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if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
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return 0;
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return 0;
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