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authorLinus Torvalds <torvalds@linux-foundation.org>2023-06-27 14:14:30 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2023-06-27 14:14:30 -0700
commitbc6cb4d5bc3a44197de30784eae71d8ba28483eb (patch)
treefdd00391c6068c217eeb8a4a06afc40cc1fc6853 /kernel/locking/lockdep.c
parented3b7923a816ded62dccef377c9ee346c7d3b1b4 (diff)
parentb33eb50a92b0a298fa8a6ac350e741c3ec100f6d (diff)
Merge tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar: - Introduce cmpxchg128() -- aka. the demise of cmpxchg_double() The cmpxchg128() family of functions is basically & functionally the same as cmpxchg_double(), but with a saner interface. Instead of a 6-parameter horror that forced u128 - u64/u64-halves layout details on the interface and exposed users to complexity, fragility & bugs, use a natural 3-parameter interface with u128 types. - Restructure the generated atomic headers, and add kerneldoc comments for all of the generic atomic{,64,_long}_t operations. The generated definitions are much cleaner now, and come with documentation. - Implement lock_set_cmp_fn() on lockdep, for defining an ordering when taking multiple locks of the same type. This gets rid of one use of lockdep_set_novalidate_class() in the bcache code. - Fix raw_cpu_generic_try_cmpxchg() bug due to an unintended variable shadowing generating garbage code on Clang on certain ARM builds. * tag 'locking-core-2023-06-27' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (43 commits) locking/atomic: scripts: fix ${atomic}_dec_if_positive() kerneldoc percpu: Fix self-assignment of __old in raw_cpu_generic_try_cmpxchg() locking/atomic: treewide: delete arch_atomic_*() kerneldoc locking/atomic: docs: Add atomic operations to the driver basic API documentation locking/atomic: scripts: generate kerneldoc comments docs: scripts: kernel-doc: accept bitwise negation like ~@var locking/atomic: scripts: simplify raw_atomic*() definitions locking/atomic: scripts: simplify raw_atomic_long*() definitions locking/atomic: scripts: split pfx/name/sfx/order locking/atomic: scripts: restructure fallback ifdeffery locking/atomic: scripts: build raw_atomic_long*() directly locking/atomic: treewide: use raw_atomic*_<op>() locking/atomic: scripts: add trivial raw_atomic*_<op>() locking/atomic: scripts: factor out order template generation locking/atomic: scripts: remove leftover "${mult}" locking/atomic: scripts: remove bogus order parameter locking/atomic: xtensa: add preprocessor symbols locking/atomic: x86: add preprocessor symbols locking/atomic: sparc: add preprocessor symbols locking/atomic: sh: add preprocessor symbols ...
Diffstat (limited to 'kernel/locking/lockdep.c')
-rw-r--r--kernel/locking/lockdep.c118
1 files changed, 87 insertions, 31 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 4dfd2f3e09b2..111607d91489 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -709,7 +709,7 @@ 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 __print_lock_name(struct held_lock *hlock, struct lock_class *class)
{
char str[KSYM_NAME_LEN];
const char *name;
@@ -724,17 +724,19 @@ static void __print_lock_name(struct lock_class *class)
printk(KERN_CONT "#%d", class->name_version);
if (class->subclass)
printk(KERN_CONT "/%d", class->subclass);
+ if (hlock && class->print_fn)
+ class->print_fn(hlock->instance);
}
}
-static void print_lock_name(struct lock_class *class)
+static void print_lock_name(struct held_lock *hlock, struct lock_class *class)
{
char usage[LOCK_USAGE_CHARS];
get_usage_chars(class, usage);
printk(KERN_CONT " (");
- __print_lock_name(class);
+ __print_lock_name(hlock, class);
printk(KERN_CONT "){%s}-{%d:%d}", usage,
class->wait_type_outer ?: class->wait_type_inner,
class->wait_type_inner);
@@ -772,7 +774,7 @@ static void print_lock(struct held_lock *hlock)
}
printk(KERN_CONT "%px", hlock->instance);
- print_lock_name(lock);
+ print_lock_name(hlock, lock);
printk(KERN_CONT ", at: %pS\n", (void *)hlock->acquire_ip);
}
@@ -1868,7 +1870,7 @@ print_circular_bug_entry(struct lock_list *target, int depth)
if (debug_locks_silent)
return;
printk("\n-> #%u", depth);
- print_lock_name(target->class);
+ print_lock_name(NULL, target->class);
printk(KERN_CONT ":\n");
print_lock_trace(target->trace, 6);
}
@@ -1899,11 +1901,11 @@ print_circular_lock_scenario(struct held_lock *src,
*/
if (parent != source) {
printk("Chain exists of:\n ");
- __print_lock_name(source);
+ __print_lock_name(src, source);
printk(KERN_CONT " --> ");
- __print_lock_name(parent);
+ __print_lock_name(NULL, parent);
printk(KERN_CONT " --> ");
- __print_lock_name(target);
+ __print_lock_name(tgt, target);
printk(KERN_CONT "\n\n");
}
@@ -1914,13 +1916,13 @@ print_circular_lock_scenario(struct held_lock *src,
printk(" rlock(");
else
printk(" lock(");
- __print_lock_name(target);
+ __print_lock_name(tgt, target);
printk(KERN_CONT ");\n");
printk(" lock(");
- __print_lock_name(parent);
+ __print_lock_name(NULL, parent);
printk(KERN_CONT ");\n");
printk(" lock(");
- __print_lock_name(target);
+ __print_lock_name(tgt, target);
printk(KERN_CONT ");\n");
if (src_read != 0)
printk(" rlock(");
@@ -1928,7 +1930,7 @@ print_circular_lock_scenario(struct held_lock *src,
printk(" sync(");
else
printk(" lock(");
- __print_lock_name(source);
+ __print_lock_name(src, source);
printk(KERN_CONT ");\n");
printk("\n *** DEADLOCK ***\n\n");
}
@@ -2154,6 +2156,8 @@ check_path(struct held_lock *target, struct lock_list *src_entry,
return ret;
}
+static void print_deadlock_bug(struct task_struct *, struct held_lock *, struct held_lock *);
+
/*
* Prove that the dependency graph starting at <src> can not
* lead to <target>. If it can, there is a circle when adding
@@ -2185,7 +2189,10 @@ check_noncircular(struct held_lock *src, struct held_lock *target,
*trace = save_trace();
}
- print_circular_bug(&src_entry, target_entry, src, target);
+ if (src->class_idx == target->class_idx)
+ print_deadlock_bug(current, src, target);
+ else
+ print_circular_bug(&src_entry, target_entry, src, target);
}
return ret;
@@ -2346,7 +2353,7 @@ static void print_lock_class_header(struct lock_class *class, int depth)
int bit;
printk("%*s->", depth, "");
- print_lock_name(class);
+ print_lock_name(NULL, class);
#ifdef CONFIG_DEBUG_LOCKDEP
printk(KERN_CONT " ops: %lu", debug_class_ops_read(class));
#endif
@@ -2528,11 +2535,11 @@ print_irq_lock_scenario(struct lock_list *safe_entry,
*/
if (middle_class != unsafe_class) {
printk("Chain exists of:\n ");
- __print_lock_name(safe_class);
+ __print_lock_name(NULL, safe_class);
printk(KERN_CONT " --> ");
- __print_lock_name(middle_class);
+ __print_lock_name(NULL, middle_class);
printk(KERN_CONT " --> ");
- __print_lock_name(unsafe_class);
+ __print_lock_name(NULL, unsafe_class);
printk(KERN_CONT "\n\n");
}
@@ -2540,18 +2547,18 @@ print_irq_lock_scenario(struct lock_list *safe_entry,
printk(" CPU0 CPU1\n");
printk(" ---- ----\n");
printk(" lock(");
- __print_lock_name(unsafe_class);
+ __print_lock_name(NULL, unsafe_class);
printk(KERN_CONT ");\n");
printk(" local_irq_disable();\n");
printk(" lock(");
- __print_lock_name(safe_class);
+ __print_lock_name(NULL, safe_class);
printk(KERN_CONT ");\n");
printk(" lock(");
- __print_lock_name(middle_class);
+ __print_lock_name(NULL, middle_class);
printk(KERN_CONT ");\n");
printk(" <Interrupt>\n");
printk(" lock(");
- __print_lock_name(safe_class);
+ __print_lock_name(NULL, safe_class);
printk(KERN_CONT ");\n");
printk("\n *** DEADLOCK ***\n\n");
}
@@ -2588,20 +2595,20 @@ print_bad_irq_dependency(struct task_struct *curr,
pr_warn("\nand this task is already holding:\n");
print_lock(prev);
pr_warn("which would create a new lock dependency:\n");
- print_lock_name(hlock_class(prev));
+ print_lock_name(prev, hlock_class(prev));
pr_cont(" ->");
- print_lock_name(hlock_class(next));
+ print_lock_name(next, hlock_class(next));
pr_cont("\n");
pr_warn("\nbut this new dependency connects a %s-irq-safe lock:\n",
irqclass);
- print_lock_name(backwards_entry->class);
+ print_lock_name(NULL, backwards_entry->class);
pr_warn("\n... which became %s-irq-safe at:\n", irqclass);
print_lock_trace(backwards_entry->class->usage_traces[bit1], 1);
pr_warn("\nto a %s-irq-unsafe lock:\n", irqclass);
- print_lock_name(forwards_entry->class);
+ print_lock_name(NULL, forwards_entry->class);
pr_warn("\n... which became %s-irq-unsafe at:\n", irqclass);
pr_warn("...");
@@ -2971,10 +2978,10 @@ print_deadlock_scenario(struct held_lock *nxt, struct held_lock *prv)
printk(" CPU0\n");
printk(" ----\n");
printk(" lock(");
- __print_lock_name(prev);
+ __print_lock_name(prv, prev);
printk(KERN_CONT ");\n");
printk(" lock(");
- __print_lock_name(next);
+ __print_lock_name(nxt, next);
printk(KERN_CONT ");\n");
printk("\n *** DEADLOCK ***\n\n");
printk(" May be due to missing lock nesting notation\n\n");
@@ -2984,6 +2991,8 @@ static void
print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
struct held_lock *next)
{
+ struct lock_class *class = hlock_class(prev);
+
if (!debug_locks_off_graph_unlock() || debug_locks_silent)
return;
@@ -2998,6 +3007,11 @@ print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
pr_warn("\nbut task is already holding lock:\n");
print_lock(prev);
+ if (class->cmp_fn) {
+ pr_warn("and the lock comparison function returns %i:\n",
+ class->cmp_fn(prev->instance, next->instance));
+ }
+
pr_warn("\nother info that might help us debug this:\n");
print_deadlock_scenario(next, prev);
lockdep_print_held_locks(curr);
@@ -3019,6 +3033,7 @@ print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
static int
check_deadlock(struct task_struct *curr, struct held_lock *next)
{
+ struct lock_class *class;
struct held_lock *prev;
struct held_lock *nest = NULL;
int i;
@@ -3039,6 +3054,12 @@ check_deadlock(struct task_struct *curr, struct held_lock *next)
if ((next->read == 2) && prev->read)
continue;
+ class = hlock_class(prev);
+
+ if (class->cmp_fn &&
+ class->cmp_fn(prev->instance, next->instance) < 0)
+ continue;
+
/*
* We're holding the nest_lock, which serializes this lock's
* nesting behaviour.
@@ -3100,6 +3121,14 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
return 2;
}
+ if (prev->class_idx == next->class_idx) {
+ struct lock_class *class = hlock_class(prev);
+
+ if (class->cmp_fn &&
+ class->cmp_fn(prev->instance, next->instance) < 0)
+ return 2;
+ }
+
/*
* Prove that the new <prev> -> <next> dependency would not
* create a circular dependency in the graph. (We do this by
@@ -3576,7 +3605,7 @@ static void print_chain_keys_chain(struct lock_chain *chain)
hlock_id = chain_hlocks[chain->base + i];
chain_key = print_chain_key_iteration(hlock_id, chain_key);
- print_lock_name(lock_classes + chain_hlock_class_idx(hlock_id));
+ print_lock_name(NULL, lock_classes + chain_hlock_class_idx(hlock_id));
printk("\n");
}
}
@@ -3933,11 +3962,11 @@ static void print_usage_bug_scenario(struct held_lock *lock)
printk(" CPU0\n");
printk(" ----\n");
printk(" lock(");
- __print_lock_name(class);
+ __print_lock_name(lock, class);
printk(KERN_CONT ");\n");
printk(" <Interrupt>\n");
printk(" lock(");
- __print_lock_name(class);
+ __print_lock_name(lock, class);
printk(KERN_CONT ");\n");
printk("\n *** DEADLOCK ***\n\n");
}
@@ -4023,7 +4052,7 @@ print_irq_inversion_bug(struct task_struct *curr,
pr_warn("but this lock took another, %s-unsafe lock in the past:\n", irqclass);
else
pr_warn("but this lock was taken by another, %s-safe lock in the past:\n", irqclass);
- print_lock_name(other->class);
+ print_lock_name(NULL, other->class);
pr_warn("\n\nand interrupts could create inverse lock ordering between them.\n\n");
pr_warn("\nother info that might help us debug this:\n");
@@ -4896,6 +4925,33 @@ EXPORT_SYMBOL_GPL(lockdep_init_map_type);
struct lock_class_key __lockdep_no_validate__;
EXPORT_SYMBOL_GPL(__lockdep_no_validate__);
+#ifdef CONFIG_PROVE_LOCKING
+void lockdep_set_lock_cmp_fn(struct lockdep_map *lock, lock_cmp_fn cmp_fn,
+ lock_print_fn print_fn)
+{
+ struct lock_class *class = lock->class_cache[0];
+ unsigned long flags;
+
+ raw_local_irq_save(flags);
+ lockdep_recursion_inc();
+
+ if (!class)
+ class = register_lock_class(lock, 0, 0);
+
+ if (class) {
+ WARN_ON(class->cmp_fn && class->cmp_fn != cmp_fn);
+ WARN_ON(class->print_fn && class->print_fn != print_fn);
+
+ class->cmp_fn = cmp_fn;
+ class->print_fn = print_fn;
+ }
+
+ lockdep_recursion_finish();
+ raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lockdep_set_lock_cmp_fn);
+#endif
+
static void
print_lock_nested_lock_not_held(struct task_struct *curr,
struct held_lock *hlock)