[PATCH] lockdep: Dump info via tracing

Jan Kara
2014-10-10T14:24:14Z

kernel/locking/lockdep.c | 707 +++++++++++++++++++++++++++--------------------
1 file changed, 402 insertions(+), 305 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index d24e4339b46d..b15e7dec55f6 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -77,6 +77,26 @@ module_param(lock_stat, int, 0644);
*/
static arch_spinlock_t lockdep_lock = (arch_spinlock_t)__ARCH_SPIN_LOCK_UNLOCKED;

+static void sprint_ip_sym(char *buf, unsigned long ip)
+{
+ sprintf(buf, "[<%p>] %pS\n", (void *) ip, (void *) ip);
+}
+
+static void trace_print_stack_trace(struct stack_trace *trace, int spaces)
+{
+ int i, n;
+ char buf[256];
+
+ if (!trace->entries)
+ return;
+
+ for (i = 0; i < trace->nr_entries; i++) {
+ n = sprintf(buf, "%*c", 1 + spaces, ' ');
+ sprint_ip_sym(buf + n, trace->entries[i]);
+ trace_printk(buf);
+ }
+}
+
static int graph_lock(void)
{
arch_spin_lock(&lockdep_lock);
@@ -382,9 +402,9 @@ static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];

static void print_lockdep_off(const char *bug_msg)
{
- printk(KERN_DEBUG "%s\n", bug_msg);
- printk(KERN_DEBUG "turning off the locking correctness validator.\n");
- printk(KERN_DEBUG "Please attach the output of /proc/lock_stat to the bug report\n");
+ trace_printk("%s\n", bug_msg);
+ trace_printk("turning off the locking correctness validator.\n");
+ trace_printk("Please attach the output of /proc/lock_stat to the bug report\n");
}

static int save_trace(struct stack_trace *trace)
@@ -417,7 +437,7 @@ static int save_trace(struct stack_trace *trace)
return 0;

print_lockdep_off("BUG: MAX_STACK_TRACE_ENTRIES too low!");
- dump_stack();
+ trace_dump_stack(0);

return 0;
}
@@ -506,7 +526,7 @@ void get_usage_chars(struct lock_class *class, char usage[LOCK_USAGE_CHARS])
usage[i] = '\0';
}

-static void __print_lock_name(struct lock_class *class)
+static void __sprint_lock_name(char *buf, struct lock_class *class)
{
char str[KSYM_NAME_LEN];
const char *name;
@@ -514,28 +534,28 @@ static void __print_lock_name(struct lock_class *class)
name = class->name;
if (!name) {
name = __get_key_name(class->key, str);
- printk("%s", name);
+ strcpy(buf, name);
} else {
- printk("%s", name);
+ strcpy(buf, name);
if (class->name_version > 1)
- printk("#%d", class->name_version);
+ sprintf(buf + strlen(buf), "#%d", class->name_version);
if (class->subclass)
- printk("/%d", class->subclass);
+ sprintf(buf + strlen(buf), "/%d", class->subclass);
}
}

-static void print_lock_name(struct lock_class *class)
+static void sprint_lock_name(char *buf, struct lock_class *class)
{
char usage[LOCK_USAGE_CHARS];

get_usage_chars(class, usage);

- printk(" (");
- __print_lock_name(class);
- printk("){%s}", usage);
+ strcpy(buf, " (");
+ __sprint_lock_name(buf, class);
+ sprintf(buf + strlen(buf), "){%s}", usage);
}

-static void print_lockdep_cache(struct lockdep_map *lock)
+static void sprint_lockdep_cache(char *buf, struct lockdep_map *lock)
{
const char *name;
char str[KSYM_NAME_LEN];
@@ -544,14 +564,14 @@ static void print_lockdep_cache(struct lockdep_map *lock)
if (!name)
name = __get_key_name(lock->key->subkeys, str);

- printk("%s", name);
+ strcpy(buf, name);
}

-static void print_lock(struct held_lock *hlock)
+static void sprint_lock(char *buf, struct held_lock *hlock)
{
- print_lock_name(hlock_class(hlock));
- printk(", at: ");
- print_ip_sym(hlock->acquire_ip);
+ sprint_lock_name(buf, hlock_class(hlock));
+ strcat(buf, ", at: ");
+ sprint_ip_sym(buf + strlen(buf), hlock->acquire_ip);
}

static void lockdep_print_held_locks(struct task_struct *curr)
@@ -559,21 +579,24 @@ static void lockdep_print_held_locks(struct task_struct *curr)
int i, depth = curr->lockdep_depth;

if (!depth) {
- printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
+ trace_printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
return;
}
- printk("%d lock%s held by %s/%d:\n",
+ trace_printk("%d lock%s held by %s/%d:\n",
depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));

for (i = 0; i < depth; i++) {
- printk(" #%d: ", i);
- print_lock(curr->held_locks + i);
+ char buf[256];
+
+ sprintf(buf, " #%d: ", i);
+ sprint_lock(buf + strlen(buf), curr->held_locks + i);
+ trace_printk(buf);
}
}

static void print_kernel_ident(void)
{
- printk("%s %.*s %s\n", init_utsname()->release,
+ trace_printk("%s %.*s %s\n", init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version,
print_tainted());
@@ -669,11 +692,11 @@ look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)

if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
debug_locks_off();
- printk(KERN_ERR
+ trace_printk(
"BUG: looking up invalid subclass: %u\n", subclass);
- printk(KERN_ERR
+ trace_printk(KERN_ERR
"turning off the locking correctness validator.\n");
- dump_stack();
+ trace_dump_stack(0);
return NULL;
}

@@ -737,10 +760,10 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
*/
if (!static_obj(lock->key)) {
debug_locks_off();
- printk("INFO: trying to register non-static key.\n");
- printk("the code is fine but needs lockdep annotation.\n");
- printk("turning off the locking correctness validator.\n");
- dump_stack();
+ trace_printk("INFO: trying to register non-static key.\n");
+ trace_printk("the code is fine but needs lockdep annotation.\n");
+ trace_printk("turning off the locking correctness validator.\n");
+ trace_dump_stack(0);

return NULL;
}
@@ -772,7 +795,7 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
raw_local_irq_restore(flags);

print_lockdep_off("BUG: MAX_LOCKDEP_KEYS too low!");
- dump_stack();
+ trace_dump_stack(0);
return NULL;
}
class = lock_classes + nr_lock_classes++;
@@ -798,11 +821,11 @@ register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
graph_unlock();
raw_local_irq_restore(flags);

- printk("\nnew class %p: %s", class->key, class->name);
+ trace_printk("\nnew class %p: %s", class->key, class->name);
if (class->name_version > 1)
- printk("#%d", class->name_version);
- printk("\n");
- dump_stack();
+ trace_printk("#%d", class->name_version);
+ trace_printk("\n");
+ trace_dump_stack(0);

raw_local_irq_save(flags);
if (!graph_lock()) {
@@ -842,7 +865,7 @@ static struct lock_list *alloc_list_entry(void)
return NULL;

print_lockdep_off("BUG: MAX_LOCKDEP_ENTRIES too low!");
- dump_stack();
+ trace_dump_stack(0);
return NULL;
}
return list_entries + nr_list_entries++;
@@ -1078,12 +1101,15 @@ static inline int __bfs_backwards(struct lock_list *src_entry,
static noinline int
print_circular_bug_entry(struct lock_list *target, int depth)
{
+ char buf[256];
+
if (debug_locks_silent)
return 0;
- printk("\n-> #%u", depth);
- print_lock_name(target->class);
- printk(":\n");
- print_stack_trace(&target->trace, 6);
+ sprintf(buf, "\n-> #%u", depth);
+ sprint_lock_name(buf + strlen(buf), target->class);
+ strcat(buf, ":\n");
+ trace_printk(buf);
+ trace_print_stack_trace(&target->trace, 6);

return 0;
}
@@ -1096,6 +1122,7 @@ print_circular_lock_scenario(struct held_lock *src,
struct lock_class *source = hlock_class(src);
struct lock_class *target = hlock_class(tgt);
struct lock_class *parent = prt->class;
+ char buf[256];

/*
* A direct locking problem where unsafe_class lock is taken
@@ -1111,31 +1138,36 @@ print_circular_lock_scenario(struct held_lock *src,
* from the safe_class lock to the unsafe_class lock.
*/
if (parent != source) {
- printk("Chain exists of:\n ");
- __print_lock_name(source);
- printk(" --> ");
- __print_lock_name(parent);
- printk(" --> ");
- __print_lock_name(target);
- printk("\n\n");
+ trace_printk("Chain exists of:\n ");
+ __sprint_lock_name(buf, source);
+ strcat(buf, " --> ");
+ __sprint_lock_name(buf + strlen(buf), parent);
+ strcat(buf, " --> ");
+ __sprint_lock_name(buf + strlen(buf), target);
+ strcat(buf, "\n\n");
+ trace_printk(buf);
}

- printk(" Possible unsafe locking scenario:\n\n");
- printk(" CPU0 CPU1\n");
- printk(" ---- ----\n");
- printk(" lock(");
- __print_lock_name(target);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(parent);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(target);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(source);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
+ trace_printk(" Possible unsafe locking scenario:\n\n");
+ trace_printk(" CPU0 CPU1\n");
+ trace_printk(" ---- ----\n");
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), target);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), parent);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), target);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), source);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ trace_printk("\n *** DEADLOCK ***\n\n");
}

/*
@@ -1148,22 +1180,25 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth,
struct held_lock *check_tgt)
{
struct task_struct *curr = current;
+ char buf[256];

if (debug_locks_silent)
return 0;

- printk("\n");
- printk("======================================================\n");
- printk("[ INFO: possible circular locking dependency detected ]\n");
+ trace_printk("\n");
+ trace_printk("======================================================\n");
+ trace_printk("[ INFO: possible circular locking dependency detected ]\n");
print_kernel_ident();
- printk("-------------------------------------------------------\n");
- printk("%s/%d is trying to acquire lock:\n",
+ trace_printk("-------------------------------------------------------\n");
+ sprintf(buf, "%s/%d is trying to acquire lock:\n",
curr->comm, task_pid_nr(curr));
- print_lock(check_src);
- printk("\nbut task is already holding lock:\n");
- print_lock(check_tgt);
- printk("\nwhich lock already depends on the new lock.\n\n");
- printk("\nthe existing dependency chain (in reverse order) is:\n");
+ sprint_lock(buf + strlen(buf), check_src);
+ trace_printk(buf);
+ trace_printk("\nbut task is already holding lock:\n");
+ sprint_lock(buf, check_tgt);
+ trace_printk(buf);
+ trace_printk("\nwhich lock already depends on the new lock.\n\n");
+ trace_printk("\nthe existing dependency chain (in reverse order) is:\n");

print_circular_bug_entry(entry, depth);

@@ -1203,14 +1238,14 @@ static noinline int print_circular_bug(struct lock_list *this,
parent = get_lock_parent(parent);
}

- printk("\nother info that might help us debug this:\n\n");
+ trace_printk("\nother info that might help us debug this:\n\n");
print_circular_lock_scenario(check_src, check_tgt,
first_parent);

lockdep_print_held_locks(curr);

- printk("\nstack backtrace:\n");
- dump_stack();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);

return 0;
}
@@ -1367,25 +1402,28 @@ find_usage_backwards(struct lock_list *root, enum lock_usage_bit bit,
static void print_lock_class_header(struct lock_class *class, int depth)
{
int bit;
+ char buf[256];

- printk("%*s->", depth, "");
- print_lock_name(class);
- printk(" ops: %lu", class->ops);
- printk(" {\n");
+ sprintf(buf, "%*s->", depth, "");
+ sprint_lock_name(buf + strlen(buf), class);
+ sprintf(buf + strlen(buf), " ops: %lu {\n", class->ops);
+ trace_printk(buf);

for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
if (class->usage_mask & (1 << bit)) {
int len = depth;

- len += printk("%*s %s", depth, "", usage_str[bit]);
- len += printk(" at:\n");
- print_stack_trace(class->usage_traces + bit, len);
+ len += sprintf(buf, "%*s %s", depth, "", usage_str[bit]);
+ len += sprintf(buf + strlen(buf), " at:\n");
+ trace_printk(buf);
+ trace_print_stack_trace(class->usage_traces + bit, len);
}
}
- printk("%*s }\n", depth, "");
+ trace_printk("%*s }\n", depth, "");

- printk("%*s ... key at: ",depth,"");
- print_ip_sym((unsigned long)class->key);
+ sprintf(buf, "%*s ... key at: ",depth,"");
+ sprint_ip_sym(buf + strlen(buf), (unsigned long)class->key);
+ trace_printk(buf);
}

/*
@@ -1403,12 +1441,12 @@ print_shortest_lock_dependencies(struct lock_list *leaf,

do {
print_lock_class_header(entry->class, depth);
- printk("%*s ... acquired at:\n", depth, "");
- print_stack_trace(&entry->trace, 2);
- printk("\n");
+ trace_printk("%*s ... acquired at:\n", depth, "");
+ trace_print_stack_trace(&entry->trace, 2);
+ trace_printk("\n");

if (depth == 0 && (entry != root)) {
- printk("lockdep:%s bad path found in chain graph\n", __func__);
+ trace_printk("lockdep:%s bad path found in chain graph\n", __func__);
break;
}

@@ -1428,6 +1466,7 @@ print_irq_lock_scenario(struct lock_list *safe_entry,
struct lock_class *safe_class = safe_entry->class;
struct lock_class *unsafe_class = unsafe_entry->class;
struct lock_class *middle_class = prev_class;
+ char buf[256];

if (middle_class == safe_class)
middle_class = next_class;
@@ -1446,33 +1485,39 @@ print_irq_lock_scenario(struct lock_list *safe_entry,
* from the safe_class lock to the unsafe_class lock.
*/
if (middle_class != unsafe_class) {
- printk("Chain exists of:\n ");
- __print_lock_name(safe_class);
- printk(" --> ");
- __print_lock_name(middle_class);
- printk(" --> ");
- __print_lock_name(unsafe_class);
- printk("\n\n");
+ trace_printk("Chain exists of:\n");
+ strcpy(buf, " ");
+ __sprint_lock_name(buf + strlen(buf), safe_class);
+ strcat(buf, " --> ");
+ __sprint_lock_name(buf + strlen(buf), middle_class);
+ strcat(buf, " --> ");
+ __sprint_lock_name(buf + strlen(buf), unsafe_class);
+ strcat(buf, "\n\n");
+ trace_printk(buf);
}

- printk(" Possible interrupt unsafe locking scenario:\n\n");
- printk(" CPU0 CPU1\n");
- printk(" ---- ----\n");
- printk(" lock(");
- __print_lock_name(unsafe_class);
- printk(");\n");
- printk(" local_irq_disable();\n");
- printk(" lock(");
- __print_lock_name(safe_class);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(middle_class);
- printk(");\n");
- printk(" <Interrupt>\n");
- printk(" lock(");
- __print_lock_name(safe_class);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
+ trace_printk(" Possible interrupt unsafe locking scenario:\n\n");
+ trace_printk(" CPU0 CPU1\n");
+ trace_printk(" ---- ----\n");
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), unsafe_class);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ trace_printk(" local_irq_disable();\n");
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), safe_class);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), middle_class);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ trace_printk(" <Interrupt>\n");
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), safe_class);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ trace_printk("\n *** DEADLOCK ***\n\n");
}

static int
@@ -1487,65 +1532,74 @@ print_bad_irq_dependency(struct task_struct *curr,
enum lock_usage_bit bit2,
const char *irqclass)
{
+ char buf[256];
+
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return 0;

- printk("\n");
- printk("======================================================\n");
- printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
+ trace_printk("\n");
+ trace_printk("======================================================\n");
+ trace_printk("[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
irqclass, irqclass);
print_kernel_ident();
- printk("------------------------------------------------------\n");
- printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
+ trace_printk("------------------------------------------------------\n");
+ trace_printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
curr->comm, task_pid_nr(curr),
curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
curr->hardirqs_enabled,
curr->softirqs_enabled);
- print_lock(next);
-
- printk("\nand this task is already holding:\n");
- print_lock(prev);
- printk("which would create a new lock dependency:\n");
- print_lock_name(hlock_class(prev));
- printk(" ->");
- print_lock_name(hlock_class(next));
- printk("\n");
-
- printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
+ sprint_lock(buf, next);
+ trace_printk(buf);
+
+ trace_printk("\nand this task is already holding:\n");
+ sprint_lock(buf, prev);
+ trace_printk(buf);
+ trace_printk("which would create a new lock dependency:\n");
+ sprint_lock_name(buf, hlock_class(prev));
+ strcat(buf, " ->");
+ sprint_lock_name(buf + strlen(buf), hlock_class(next));
+ strcat(buf, "\n");
+ trace_printk(buf);
+
+ trace_printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
irqclass);
- print_lock_name(backwards_entry->class);
- printk("\n... which became %s-irq-safe at:\n", irqclass);
+ sprint_lock_name(buf, backwards_entry->class);
+ strcat(buf, "\n");
+ trace_printk(buf);
+ trace_printk("... which became %s-irq-safe at:\n", irqclass);

- print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);
+ trace_print_stack_trace(backwards_entry->class->usage_traces + bit1, 1);

- printk("\nto a %s-irq-unsafe lock:\n", irqclass);
- print_lock_name(forwards_entry->class);
- printk("\n... which became %s-irq-unsafe at:\n", irqclass);
- printk("...");
+ trace_printk("\nto a %s-irq-unsafe lock:\n", irqclass);
+ sprint_lock_name(buf, forwards_entry->class);
+ strcat(buf, "\n");
+ trace_printk(buf);
+ trace_printk("... which became %s-irq-unsafe at:\n", irqclass);
+ trace_printk("...");

- print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);
+ trace_print_stack_trace(forwards_entry->class->usage_traces + bit2, 1);

- printk("\nother info that might help us debug this:\n\n");
+ trace_printk("\nother info that might help us debug this:\n\n");
print_irq_lock_scenario(backwards_entry, forwards_entry,
hlock_class(prev), hlock_class(next));

lockdep_print_held_locks(curr);

- printk("\nthe dependencies between %s-irq-safe lock", irqclass);
- printk(" and the holding lock:\n");
+ trace_printk("\nthe dependencies between %s-irq-safe lock", irqclass);
+ trace_printk(" and the holding lock:\n");
if (!save_trace(&prev_root->trace))
return 0;
print_shortest_lock_dependencies(backwards_entry, prev_root);

- printk("\nthe dependencies between the lock to be acquired");
- printk(" and %s-irq-unsafe lock:\n", irqclass);
+ trace_printk("\nthe dependencies between the lock to be acquired");
+ trace_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();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);

return 0;
}
@@ -1699,44 +1753,51 @@ print_deadlock_scenario(struct held_lock *nxt,
{
struct lock_class *next = hlock_class(nxt);
struct lock_class *prev = hlock_class(prv);
-
- printk(" Possible unsafe locking scenario:\n\n");
- printk(" CPU0\n");
- printk(" ----\n");
- printk(" lock(");
- __print_lock_name(prev);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(next);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
- printk(" May be due to missing lock nesting notation\n\n");
+ char buf[256];
+
+ trace_printk(" Possible unsafe locking scenario:\n\n");
+ trace_printk(" CPU0\n");
+ trace_printk(" ----\n");
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), prev);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), next);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ trace_printk("\n *** DEADLOCK ***\n\n");
+ trace_printk(" May be due to missing lock nesting notation\n\n");
}

static int
print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
struct held_lock *next)
{
+ char buf[256];
+
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return 0;

- printk("\n");
- printk("=============================================\n");
- printk("[ INFO: possible recursive locking detected ]\n");
+ trace_printk("\n");
+ trace_printk("=============================================\n");
+ trace_printk("[ INFO: possible recursive locking detected ]\n");
print_kernel_ident();
- printk("---------------------------------------------\n");
- printk("%s/%d is trying to acquire lock:\n",
+ trace_printk("---------------------------------------------\n");
+ trace_printk("%s/%d is trying to acquire lock:\n",
curr->comm, task_pid_nr(curr));
- print_lock(next);
- printk("\nbut task is already holding lock:\n");
- print_lock(prev);
+ sprint_lock(buf, next);
+ trace_printk(buf);
+ trace_printk("\nbut task is already holding lock:\n");
+ sprint_lock(buf, prev);
+ trace_printk(buf);

- printk("\nother info that might help us debug this:\n");
+ trace_printk("\nother info that might help us debug this:\n");
print_deadlock_scenario(next, prev);
lockdep_print_held_locks(curr);

- printk("\nstack backtrace:\n");
- dump_stack();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);

return 0;
}
@@ -1894,13 +1955,16 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
* Debugging printouts:
*/
if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
+ char buf[256];
+
graph_unlock();
- printk("\n new dependency: ");
- print_lock_name(hlock_class(prev));
- printk(" => ");
- print_lock_name(hlock_class(next));
- printk("\n");
- dump_stack();
+ strcpy(buf, "\n new dependency: ");
+ sprint_lock_name(buf + strlen(buf), hlock_class(prev));
+ strcat(buf, " => ");
+ sprint_lock_name(buf + strlen(buf), hlock_class(next));
+ strcat(buf, "\n");
+ trace_printk(buf);
+ trace_dump_stack(0);
return graph_lock();
}
return 1;
@@ -2025,7 +2089,7 @@ static inline int lookup_chain_cache(struct task_struct *curr,
cache_hit:
debug_atomic_inc(chain_lookup_hits);
if (very_verbose(class))
- printk("\nhash chain already cached, key: "
+ trace_printk("\nhash chain already cached, key: "
"%016Lx tail class: [%p] %s\n",
(unsigned long long)chain_key,
class->key, class->name);
@@ -2033,7 +2097,7 @@ cache_hit:
}
}
if (very_verbose(class))
- printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
+ trace_printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
(unsigned long long)chain_key, class->key, class->name);
/*
* Allocate a new chain entry from the static array, and add
@@ -2055,7 +2119,7 @@ cache_hit:
return 0;

print_lockdep_off("BUG: MAX_LOCKDEP_CHAINS too low!");
- dump_stack();
+ trace_dump_stack(0);
return 0;
}
chain = lock_chains + nr_lock_chains++;
@@ -2203,55 +2267,61 @@ static void
print_usage_bug_scenario(struct held_lock *lock)
{
struct lock_class *class = hlock_class(lock);
-
- printk(" Possible unsafe locking scenario:\n\n");
- printk(" CPU0\n");
- printk(" ----\n");
- printk(" lock(");
- __print_lock_name(class);
- printk(");\n");
- printk(" <Interrupt>\n");
- printk(" lock(");
- __print_lock_name(class);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
+ char buf[256];
+
+ trace_printk(" Possible unsafe locking scenario:\n\n");
+ trace_printk(" CPU0\n");
+ trace_printk(" ----\n");
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), class);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ trace_printk(" <Interrupt>\n");
+ strcpy(buf, " lock(");
+ __sprint_lock_name(buf + strlen(buf), class);
+ strcat(buf, ");\n");
+ trace_printk(buf);
+ trace_printk("\n *** DEADLOCK ***\n\n");
}

static int
print_usage_bug(struct task_struct *curr, struct held_lock *this,
enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
{
+ char buf[256];
+
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return 0;

- printk("\n");
- printk("=================================\n");
- printk("[ INFO: inconsistent lock state ]\n");
+ trace_printk("\n");
+ trace_printk("=================================\n");
+ trace_printk("[ INFO: inconsistent lock state ]\n");
print_kernel_ident();
- printk("---------------------------------\n");
+ trace_printk("---------------------------------\n");

- printk("inconsistent {%s} -> {%s} usage.\n",
+ trace_printk("inconsistent {%s} -> {%s} usage.\n",
usage_str[prev_bit], usage_str[new_bit]);

- printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
+ trace_printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
curr->comm, task_pid_nr(curr),
trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
trace_hardirqs_enabled(curr),
trace_softirqs_enabled(curr));
- print_lock(this);
+ sprint_lock(buf, this);
+ trace_printk(buf);

- printk("{%s} state was registered at:\n", usage_str[prev_bit]);
- print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);
+ trace_printk("{%s} state was registered at:\n", usage_str[prev_bit]);
+ trace_print_stack_trace(hlock_class(this)->usage_traces + prev_bit, 1);

print_irqtrace_events(curr);
- printk("\nother info that might help us debug this:\n");
+ trace_printk("\nother info that might help us debug this:\n");
print_usage_bug_scenario(this);

lockdep_print_held_locks(curr);

- printk("\nstack backtrace:\n");
- dump_stack();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);

return 0;
}
@@ -2285,32 +2355,36 @@ print_irq_inversion_bug(struct task_struct *curr,
struct lock_list *entry = other;
struct lock_list *middle = NULL;
int depth;
+ char buf[256];

if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return 0;

- printk("\n");
- printk("=========================================================\n");
- printk("[ INFO: possible irq lock inversion dependency detected ]\n");
+ trace_printk("\n");
+ trace_printk("=========================================================\n");
+ trace_printk("[ INFO: possible irq lock inversion dependency detected ]\n");
print_kernel_ident();
- printk("---------------------------------------------------------\n");
- printk("%s/%d just changed the state of lock:\n",
+ trace_printk("---------------------------------------------------------\n");
+ trace_printk("%s/%d just changed the state of lock:\n",
curr->comm, task_pid_nr(curr));
- print_lock(this);
+ sprint_lock(buf, this);
+ trace_printk(buf);
if (forwards)
- printk("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
+ trace_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->class);
- printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
+ trace_printk("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
+ sprint_lock_name(buf, other->class);
+ strcat(buf, "\n");
+ trace_printk(buf);
+ trace_printk("\nand interrupts could create inverse lock ordering between them.\n\n");

- printk("\nother info that might help us debug this:\n");
+ trace_printk("\nother info that might help us debug this:\n");

/* Find a middle lock (if one exists) */
depth = get_lock_depth(other);
do {
if (depth == 0 && (entry != root)) {
- printk("lockdep:%s bad path found in chain graph\n", __func__);
+ trace_printk("lockdep:%s bad path found in chain graph\n", __func__);
break;
}
middle = entry;
@@ -2326,13 +2400,13 @@ print_irq_inversion_bug(struct task_struct *curr,

lockdep_print_held_locks(curr);

- printk("\nthe shortest dependencies between 2nd lock and 1st lock:\n");
+ trace_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();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);

return 0;
}
@@ -2387,15 +2461,21 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this,

void print_irqtrace_events(struct task_struct *curr)
{
- printk("irq event stamp: %u\n", curr->irq_events);
- printk("hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
- print_ip_sym(curr->hardirq_enable_ip);
- printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
- print_ip_sym(curr->hardirq_disable_ip);
- printk("softirqs last enabled at (%u): ", curr->softirq_enable_event);
- print_ip_sym(curr->softirq_enable_ip);
- printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
- print_ip_sym(curr->softirq_disable_ip);
+ char buf[256];
+
+ trace_printk("irq event stamp: %u\n", curr->irq_events);
+ sprintf(buf, "hardirqs last enabled at (%u): ", curr->hardirq_enable_event);
+ sprint_ip_sym(buf + strlen(buf), curr->hardirq_enable_ip);
+ trace_printk(buf);
+ sprintf(buf, "hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
+ sprint_ip_sym(buf + strlen(buf), curr->hardirq_disable_ip);
+ trace_printk(buf);
+ sprintf(buf, "softirqs last enabled at (%u): ", curr->softirq_enable_event);
+ sprint_ip_sym(buf + strlen(buf), curr->softirq_enable_ip);
+ trace_printk(buf);
+ sprintf(buf, "softirqs last disabled at (%u): ", curr->softirq_disable_event);
+ sprint_ip_sym(buf + strlen(buf), curr->softirq_disable_ip);
+ trace_printk(buf);
}

static int HARDIRQ_verbose(struct lock_class *class)
@@ -2937,10 +3017,13 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this,
* We must printk outside of the graph_lock:
*/
if (ret == 2) {
- printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
- print_lock(this);
+ char buf[256];
+
+ trace_printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
+ sprint_lock(buf, this);
+ trace_printk(buf);
print_irqtrace_events(curr);
- dump_stack();
+ trace_dump_stack(0);
}

return ret;
@@ -2982,7 +3065,7 @@ void lockdep_init_map(struct lockdep_map *lock, const char *name,
* Sanity check, the lock-class key must be persistent:
*/
if (!static_obj(key)) {
- printk("BUG: key %p not in .data!\n", key);
+ trace_printk("BUG: key %p not in .data!\n", key);
/*
* What it says above ^^^^^, I suggest you read it.
*/
@@ -3007,31 +3090,34 @@ print_lock_nested_lock_not_held(struct task_struct *curr,
struct held_lock *hlock,
unsigned long ip)
{
+ char buf[256];
+
if (!debug_locks_off())
return 0;
if (debug_locks_silent)
return 0;

- printk("\n");
- printk("==================================\n");
- printk("[ BUG: Nested lock was not taken ]\n");
+ trace_printk("\n");
+ trace_printk("==================================\n");
+ trace_printk("[ BUG: Nested lock was not taken ]\n");
print_kernel_ident();
- printk("----------------------------------\n");
+ trace_printk("----------------------------------\n");

- printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
- print_lock(hlock);
+ trace_printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
+ sprint_lock(buf, hlock);
+ trace_printk(buf);

- printk("\nbut this task is not holding:\n");
- printk("%s\n", hlock->nest_lock->name);
+ trace_printk("\nbut this task is not holding:\n");
+ trace_printk("%s\n", hlock->nest_lock->name);

- printk("\nstack backtrace:\n");
- dump_stack();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);

- printk("\nother info that might help us debug this:\n");
+ trace_printk("\nother info that might help us debug this:\n");
lockdep_print_held_locks(curr);

- printk("\nstack backtrace:\n");
- dump_stack();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);

return 0;
}
@@ -3081,11 +3167,11 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
}
atomic_inc((atomic_t *)&class->ops);
if (very_verbose(class)) {
- printk("\nacquire class [%p] %s", class->key, class->name);
+ trace_printk("\nacquire class [%p] %s", class->key, class->name);
if (class->name_version > 1)
- printk("#%d", class->name_version);
- printk("\n");
- dump_stack();
+ trace_printk("#%d", class->name_version);
+ trace_printk("\n");
+ trace_dump_stack(0);
}

/*
@@ -3192,12 +3278,12 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
debug_locks_off();
print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!");
- printk(KERN_DEBUG "depth: %i max: %lu!\n",
+ trace_printk("depth: %i max: %lu!\n",
curr->lockdep_depth, MAX_LOCK_DEPTH);

lockdep_print_held_locks(current);
debug_show_all_locks();
- dump_stack();
+ trace_dump_stack(0);

return 0;
}
@@ -3212,27 +3298,31 @@ static int
print_unlock_imbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
unsigned long ip)
{
+ char buf[256];
+
if (!debug_locks_off())
return 0;
if (debug_locks_silent)
return 0;

- printk("\n");
- printk("=====================================\n");
- printk("[ BUG: bad unlock balance detected! ]\n");
+ trace_printk("\n");
+ trace_printk("=====================================\n");
+ trace_printk("[ BUG: bad unlock balance detected! ]\n");
print_kernel_ident();
- printk("-------------------------------------\n");
- printk("%s/%d is trying to release lock (",
+ trace_printk("-------------------------------------\n");
+ sprintf(buf, "%s/%d is trying to release lock (",
curr->comm, task_pid_nr(curr));
- print_lockdep_cache(lock);
- printk(") at:\n");
- print_ip_sym(ip);
- printk("but there are no more locks to release!\n");
- printk("\nother info that might help us debug this:\n");
+ sprint_lockdep_cache(buf + strlen(buf), lock);
+ strcat(buf, ") at:\n");
+ trace_printk(buf);
+ sprint_ip_sym(buf, ip);
+ trace_printk(buf);
+ trace_printk("but there are no more locks to release!\n");
+ trace_printk("\nother info that might help us debug this:\n");
lockdep_print_held_locks(curr);

- printk("\nstack backtrace:\n");
- dump_stack();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);

return 0;
}
@@ -3532,11 +3622,11 @@ static void check_flags(unsigned long flags)

if (irqs_disabled_flags(flags)) {
if (DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled)) {
- printk("possible reason: unannotated irqs-off.\n");
+ trace_printk("possible reason: unannotated irqs-off.\n");
}
} else {
if (DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled)) {
- printk("possible reason: unannotated irqs-on.\n");
+ trace_printk("possible reason: unannotated irqs-on.\n");
}
}

@@ -3657,27 +3747,31 @@ static int
print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
unsigned long ip)
{
+ char buf[256];
+
if (!debug_locks_off())
return 0;
if (debug_locks_silent)
return 0;

- printk("\n");
- printk("=================================\n");
- printk("[ BUG: bad contention detected! ]\n");
+ trace_printk("\n");
+ trace_printk("=================================\n");
+ trace_printk("[ BUG: bad contention detected! ]\n");
print_kernel_ident();
- printk("---------------------------------\n");
- printk("%s/%d is trying to contend lock (",
+ trace_printk("---------------------------------\n");
+ sprintf(buf, "%s/%d is trying to contend lock (",
curr->comm, task_pid_nr(curr));
- print_lockdep_cache(lock);
- printk(") at:\n");
- print_ip_sym(ip);
- printk("but there are no locks held!\n");
- printk("\nother info that might help us debug this:\n");
+ sprint_lockdep_cache(buf + strlen(buf), lock);
+ strcat(buf, ") at:\n");
+ trace_printk(buf);
+ sprint_ip_sym(buf, ip);
+ trace_printk(buf);
+ trace_printk("but there are no locks held!\n");
+ trace_printk("\nother info that might help us debug this:\n");
lockdep_print_held_locks(curr);

- printk("\nstack backtrace:\n");
- dump_stack();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);

return 0;
}
@@ -4033,23 +4127,26 @@ static void
print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
const void *mem_to, struct held_lock *hlock)
{
+ char buf[256];
+
if (!debug_locks_off())
return;
if (debug_locks_silent)
return;

- printk("\n");
- printk("=========================\n");
- printk("[ BUG: held lock freed! ]\n");
+ trace_printk("\n");
+ trace_printk("=========================\n");
+ trace_printk("[ BUG: held lock freed! ]\n");
print_kernel_ident();
- printk("-------------------------\n");
- printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
+ trace_printk("-------------------------\n");
+ trace_printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
- print_lock(hlock);
+ sprint_lock(buf, hlock);
+ trace_printk(buf);
lockdep_print_held_locks(curr);

- printk("\nstack backtrace:\n");
- dump_stack();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);
}

static inline int not_in_range(const void* mem_from, unsigned long mem_len,
@@ -4096,15 +4193,15 @@ static void print_held_locks_bug(void)
if (debug_locks_silent)
return;

- printk("\n");
- printk("=====================================\n");
- printk("[ BUG: %s/%d still has locks held! ]\n",
+ trace_printk("\n");
+ trace_printk("=====================================\n");
+ trace_printk("[ BUG: %s/%d still has locks held! ]\n",
current->comm, task_pid_nr(current));
print_kernel_ident();
- printk("-------------------------------------\n");
+ trace_printk("-------------------------------------\n");
lockdep_print_held_locks(current);
- printk("\nstack backtrace:\n");
- dump_stack();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);
}

void debug_check_no_locks_held(void)
@@ -4195,12 +4292,12 @@ asmlinkage __visible void lockdep_sys_exit(void)
if (unlikely(curr->lockdep_depth)) {
if (!debug_locks_off())
return;
- printk("\n");
- printk("================================================\n");
- printk("[ BUG: lock held when returning to user space! ]\n");
+ trace_printk("\n");
+ trace_printk("================================================\n");
+ trace_printk("[ BUG: lock held when returning to user space! ]\n");
print_kernel_ident();
- printk("------------------------------------------------\n");
- printk("%s/%d is leaving the kernel with locks still held!\n",
+ trace_printk("------------------------------------------------\n");
+ trace_printk("%s/%d is leaving the kernel with locks still held!\n",
curr->comm, curr->pid);
lockdep_print_held_locks(curr);
}
@@ -4215,14 +4312,14 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
return;
#endif /* #ifdef CONFIG_PROVE_RCU_REPEATEDLY */
/* Note: the following can be executed concurrently, so be careful. */
- printk("\n");
- printk("===============================\n");
- printk("[ INFO: suspicious RCU usage. ]\n");
+ trace_printk("\n");
+ trace_printk("===============================\n");
+ trace_printk("[ INFO: suspicious RCU usage. ]\n");
print_kernel_ident();
- printk("-------------------------------\n");
- printk("%s:%d %s!\n", file, line, s);
- printk("\nother info that might help us debug this:\n\n");
- printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
+ trace_printk("-------------------------------\n");
+ trace_printk("%s:%d %s!\n", file, line, s);
+ trace_printk("\nother info that might help us debug this:\n\n");
+ trace_printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
!rcu_lockdep_current_cpu_online()
? "RCU used illegally from offline CPU!\n"
: !rcu_is_watching()
@@ -4249,10 +4346,10 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
* rcu_read_lock_bh() and so on from extended quiescent states.
*/
if (!rcu_is_watching())
- printk("RCU used illegally from extended quiescent state!\n");
+ trace_printk("RCU used illegally from extended quiescent state!\n");

lockdep_print_held_locks(curr);
- printk("\nstack backtrace:\n");
- dump_stack();
+ trace_printk("\nstack backtrace:\n");
+ trace_dump_stack(0);
}
EXPORT_SYMBOL_GPL(lockdep_rcu_suspicious);