diff options
| -rw-r--r-- | kernel/lockdep.c | 93 | ||||
| -rw-r--r-- | kernel/lockdep_internals.h | 4 |
2 files changed, 69 insertions, 28 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index b3ade507c6ce..938dc500f1aa 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -576,6 +576,36 @@ static void print_lock_class_header(struct lock_class *class, int depth) } /* + * printk the shortest lock dependencies from @start to @end in reverse order: + */ +static void __used +print_shortest_lock_dependencies(struct lock_list *leaf, + struct lock_list *root) +{ + struct lock_list *entry = leaf; + int depth; + + /*compute depth from generated tree by BFS*/ + depth = get_lock_depth(leaf); + + do { + print_lock_class_header(entry->class, depth); + printk("%*s ... acquired at:\n", depth, ""); + print_stack_trace(&entry->trace, 2); + printk("\n"); + + if (depth == 0 && (entry != root)) { + printk("lockdep:%s bad BFS generated tree\n", __func__); + break; + } + + entry = get_lock_parent(entry); + depth--; + } while (entry && (depth >= 0)); + + return; +} +/* * printk all lock dependencies starting at <entry>: */ static void __used @@ -992,7 +1022,7 @@ static inline int __bfs_backwards(struct lock_list *src_entry, * has been detected): */ static noinline int -print_circular_bug_entry(struct lock_list *target, unsigned int depth) +print_circular_bug_entry(struct lock_list *target, int depth) { if (debug_locks_silent) return 0; @@ -1047,7 +1077,7 @@ static noinline int print_circular_bug(struct lock_list *this, { struct task_struct *curr = current; struct lock_list *parent; - unsigned long depth; + int depth; if (!debug_locks_off_graph_unlock() || debug_locks_silent) return 0; @@ -1169,7 +1199,6 @@ check_noncircular(struct lock_list *root, struct lock_class *target, * proving that two subgraphs can be connected by a new dependency * without creating any illegal irq-safe -> irq-unsafe lock dependency. */ -static struct lock_class *forwards_match, *backwards_match; #define BFS_PROCESS_RET(ret) do { \ @@ -1235,6 +1264,10 @@ find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit, static int print_bad_irq_dependency(struct task_struct *curr, + struct lock_list *prev_root, + struct lock_list *next_root, + struct lock_list *backwards_entry, + struct lock_list *forwards_entry, struct held_lock *prev, struct held_lock *next, enum lock_usage_bit bit1, @@ -1267,26 +1300,32 @@ print_bad_irq_dependency(struct task_struct *curr, printk("\nbut this new dependency connects a %s-irq-safe lock:\n", irqclass); - print_lock_name(backwards_match); + print_lock_name(backwards_entry->class); printk("\n... which became %s-irq-safe at:\n", irqclass); - print_stack_trace(backwards_match->usage_traces + bit1, 1); + print_stack_trace(backwards_entry->class->usage_traces + bit1, 1); printk("\nto a %s-irq-unsafe lock:\n", irqclass); - print_lock_name(forwards_match); + print_lock_name(forwards_entry->class); printk("\n... which became %s-irq-unsafe at:\n", irqclass); printk("..."); - print_stack_trace(forwards_match->usage_traces + bit2, 1); + print_stack_trace(forwards_entry->class->usage_traces + bit2, 1); printk("\nother info that might help us debug this:\n\n"); lockdep_print_held_locks(curr); - printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass); - print_lock_dependencies(backwards_match, 0); + printk("\nthe dependencies between %s-irq-safe lock", irqclass); + printk(" and the holding lock:\n"); + if (!save_trace(&prev_root->trace)) + return 0; + print_shortest_lock_dependencies(backwards_entry, prev_root); - printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass); - print_lock_dependencies(forwards_match, 0); + printk("\nthe dependencies between the lock to be acquired"); + printk(" and %s-irq-unsafe lock:\n", irqclass); + if (!save_trace(&next_root->trace)) + return 0; + print_shortest_lock_dependencies(forwards_entry, next_root); printk("\nstack backtrace:\n"); dump_stack(); @@ -1300,22 +1339,24 @@ check_usage(struct task_struct *curr, struct held_lock *prev, enum lock_usage_bit bit_forwards, const char *irqclass) { int ret; - struct lock_list this; + struct lock_list this, that; struct lock_list *uninitialized_var(target_entry); + struct lock_list *uninitialized_var(target_entry1); this.parent = NULL; this.class = hlock_class(prev); ret = find_usage_backwards(&this, bit_backwards, &target_entry); BFS_PROCESS_RET(ret); - backwards_match = target_entry->class; - this.class = hlock_class(next); - ret = find_usage_forwards(&this, bit_forwards, &target_entry); + that.parent = NULL; + that.class = hlock_class(next); + ret = find_usage_forwards(&that, bit_forwards, &target_entry1); BFS_PROCESS_RET(ret); - forwards_match = target_entry->class; - return print_bad_irq_dependency(curr, prev, next, + return print_bad_irq_dependency(curr, &this, &that, + target_entry, target_entry1, + prev, next, bit_backwards, bit_forwards, irqclass); } @@ -1944,7 +1985,8 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, * print irq inversion bug: */ static int -print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, +print_irq_inversion_bug(struct task_struct *curr, + struct lock_list *root, struct lock_list *other, struct held_lock *this, int forwards, const char *irqclass) { @@ -1962,17 +2004,16 @@ print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other, printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass); else printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass); - print_lock_name(other); + print_lock_name(other->class); printk("\n\nand interrupts could create inverse lock ordering between them.\n\n"); printk("\nother info that might help us debug this:\n"); lockdep_print_held_locks(curr); - printk("\nthe first lock's dependencies:\n"); - print_lock_dependencies(hlock_class(this), 0); - - printk("\nthe second lock's dependencies:\n"); - print_lock_dependencies(other, 0); + printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n"); + if (!save_trace(&root->trace)) + return 0; + print_shortest_lock_dependencies(other, root); printk("\nstack backtrace:\n"); dump_stack(); @@ -1997,7 +2038,7 @@ check_usage_forwards(struct task_struct *curr, struct held_lock *this, ret = find_usage_forwards(&root, bit, &target_entry); BFS_PROCESS_RET(ret); - return print_irq_inversion_bug(curr, target_entry->class, + return print_irq_inversion_bug(curr, &root, target_entry, this, 1, irqclass); } @@ -2018,7 +2059,7 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this, ret = find_usage_backwards(&root, bit, &target_entry); BFS_PROCESS_RET(ret); - return print_irq_inversion_bug(curr, target_entry->class, + return print_irq_inversion_bug(curr, &root, target_entry, this, 1, irqclass); } diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h index c2f6594966f3..b115aaa0bf35 100644 --- a/kernel/lockdep_internals.h +++ b/kernel/lockdep_internals.h @@ -219,9 +219,9 @@ static inline struct lock_list *get_lock_parent(struct lock_list *child) return child->parent; } -static inline unsigned long get_lock_depth(struct lock_list *child) +static inline int get_lock_depth(struct lock_list *child) { - unsigned long depth = 0; + int depth = 0; struct lock_list *parent; while ((parent = get_lock_parent(child))) { |