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Date: Wed, 27 Sep 2017 14:42:20 -0700
From: Govindarajulu Varadarajan <gvaradar@...co.com>
To: benve@...co.com, bhelgaas@...gle.com, linux-pci@...r.kernel.org,
linux-kernel@...r.kernel.org, jlbec@...lplan.org, hch@....de,
mingo@...hat.com, peterz@...radead.org
Cc: Govindarajulu Varadarajan <gvaradar@...co.com>
Subject: [PATCH 4/4] lockdep: make MAX_LOCK_DEPTH configurable from Kconfig
Make MAX_LOCK_DEPTH configurable. It is set to 48 right now. Number of
VFs under a PCI pf bus can exceed 48 and this disables lockdep.
lockdep currently allows max of 63 held_locks.
Signed-off-by: Govindarajulu Varadarajan <gvaradar@...co.com>
---
fs/configfs/inode.c | 2 +-
include/linux/sched.h | 3 +--
kernel/locking/lockdep.c | 13 +++++++------
lib/Kconfig.debug | 10 ++++++++++
4 files changed, 19 insertions(+), 9 deletions(-)
diff --git a/fs/configfs/inode.c b/fs/configfs/inode.c
index ad718e5e37bb..a1e2a7ce69d0 100644
--- a/fs/configfs/inode.c
+++ b/fs/configfs/inode.c
@@ -41,7 +41,7 @@
#include "configfs_internal.h"
#ifdef CONFIG_LOCKDEP
-static struct lock_class_key default_group_class[MAX_LOCK_DEPTH];
+static struct lock_class_key default_group_class[CONFIG_MAX_LOCK_DEPTH];
#endif
static const struct address_space_operations configfs_aops = {
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 92fb8dd5a9e4..9a81eec702be 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -841,11 +841,10 @@ struct task_struct {
#endif
#ifdef CONFIG_LOCKDEP
-# define MAX_LOCK_DEPTH 48UL
u64 curr_chain_key;
int lockdep_depth;
unsigned int lockdep_recursion;
- struct held_lock held_locks[MAX_LOCK_DEPTH];
+ struct held_lock held_locks[CONFIG_MAX_LOCK_DEPTH];
#endif
#ifdef CONFIG_LOCKDEP_CROSSRELEASE
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 44c8d0d17170..22a4a338616d 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -3404,7 +3404,7 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
/*
* Ran out of static storage for our per-task lock stack again have we?
*/
- if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
+ if (DEBUG_LOCKS_WARN_ON(depth >= CONFIG_MAX_LOCK_DEPTH))
return 0;
class_idx = class - lock_classes + 1;
@@ -3513,11 +3513,11 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
if (unlikely(!debug_locks))
return 0;
#endif
- if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
+ if (unlikely(curr->lockdep_depth >= CONFIG_MAX_LOCK_DEPTH)) {
debug_locks_off();
print_lockdep_off("BUG: MAX_LOCK_DEPTH too low!");
printk(KERN_DEBUG "depth: %i max: %lu!\n",
- curr->lockdep_depth, MAX_LOCK_DEPTH);
+ curr->lockdep_depth, CONFIG_MAX_LOCK_DEPTH);
lockdep_print_held_locks(current);
debug_show_all_locks();
@@ -4276,7 +4276,8 @@ void lockdep_reset(void)
current->curr_chain_key = 0;
current->lockdep_depth = 0;
current->lockdep_recursion = 0;
- memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
+ memset(current->held_locks, 0,
+ CONFIG_MAX_LOCK_DEPTH * sizeof(struct held_lock));
nr_hardirq_chains = 0;
nr_softirq_chains = 0;
nr_process_chains = 0;
@@ -4421,7 +4422,7 @@ void __init lockdep_info(void)
printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
printk("... MAX_LOCKDEP_SUBCLASSES: %lu\n", MAX_LOCKDEP_SUBCLASSES);
- printk("... MAX_LOCK_DEPTH: %lu\n", MAX_LOCK_DEPTH);
+ printk("... MAX_LOCK_DEPTH: %lu\n", CONFIG_MAX_LOCK_DEPTH);
printk("... MAX_LOCKDEP_KEYS: %lu\n", MAX_LOCKDEP_KEYS);
printk("... CLASSHASH_SIZE: %lu\n", CLASSHASH_SIZE);
printk("... MAX_LOCKDEP_ENTRIES: %lu\n", MAX_LOCKDEP_ENTRIES);
@@ -4441,7 +4442,7 @@ void __init lockdep_info(void)
);
printk(" per task-struct memory footprint: %lu bytes\n",
- sizeof(struct held_lock) * MAX_LOCK_DEPTH);
+ sizeof(struct held_lock) * CONFIG_MAX_LOCK_DEPTH);
}
static void
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 2689b7c50c52..60bc084315a6 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1187,6 +1187,16 @@ config DEBUG_LOCKDEP
additional runtime checks to debug itself, at the price
of more runtime overhead.
+config MAX_LOCK_DEPTH
+ int "Maximum held_locks depth"
+ depends on DEBUG_LOCKDEP
+ default 48
+ range 1 63
+ help
+ This is maximum held_lock depth in task_struct for debugging.
+ Increment if you think a task can hold more than default(48) locks.
+ If unsure, set to default value, 48.
+
config DEBUG_ATOMIC_SLEEP
bool "Sleep inside atomic section checking"
select PREEMPT_COUNT
--
2.14.1
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