From d094595078d00b63839d0c5ccb8b184ef242cb45 Mon Sep 17 00:00:00 2001
From: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Date: Thu, 13 Sep 2012 11:39:51 +0200
Subject: [PATCH 1/2] 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>
---
kernel/lockdep.c | 39 +++++++++++++++++++++++++++++++++++++++
1 file changed, 39 insertions(+)
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index ea9ee4518c35..7981e5b2350d 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2998,6 +2998,42 @@ EXPORT_SYMBOL_GPL(lockdep_init_map);
struct lock_class_key __lockdep_no_validate__;
+static int
+print_lock_nested_lock_not_held(struct task_struct *curr,
+ struct held_lock *hlock,
+ unsigned long ip)
+{
+ if (!debug_locks_off())
+ return 0;
+ if (debug_locks_silent)
+ return 0;
+
+ printk("\n");
+ printk("==================================\n");
+ printk("[ BUG: Nested lock was not taken ]\n");
+ print_kernel_ident();
+ printk("----------------------------------\n");
+
+ printk("%s/%d is trying to lock:\n", curr->comm, task_pid_nr(curr));
+ print_lock(hlock);
+
+ printk("\nbut this task is not holding:\n");
+ printk("%s\n", hlock->nest_lock->name);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ printk("\nother info that might help us debug this:\n");
+ lockdep_print_held_locks(curr);
+
+ printk("\nstack backtrace:\n");
+ dump_stack();
+
+ return 0;
+}
+
+static int __lock_is_held(struct lockdep_map *lock);
+
/*
* This gets called for every mutex_lock*()/spin_lock*() operation.
* We maintain the dependency maps and validate the locking attempt:
@@ -3139,6 +3175,9 @@ static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
}
chain_key = iterate_chain_key(chain_key, id);
+ if (nest_lock && !__lock_is_held(nest_lock))
+ return print_lock_nested_lock_not_held(curr, hlock, ip);
+
if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
return 0;
From 4fe84fb8c6b5081f7364af63aee8e118a665b966 Mon Sep 17 00:00:00 2001
From: Jan Beulich <JBeulich@suse.com>
Date: Mon, 10 Sep 2012 13:01:16 +0100
Subject: [PATCH 2/2] locking: Adjust spin lock inlining Kconfig options
Break out the DEBUG_SPINLOCK dependency (requires moving up
UNINLINE_SPIN_UNLOCK, as this was the only one in that block not
depending on that option).
Avoid putting values not selected into the resulting .config -
they are not useful for anything, make the output less legible,
and just consume space: Use "depends on" rather than directly
setting the default from the combined dependency values.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/504DF2AC020000780009A2DF@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/Kconfig.locks | 103 ++++++++++++++++++++++++++-----------------
1 file changed, 63 insertions(+), 40 deletions(-)
diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
index 2251882daf53..44511d100eaa 100644
--- a/kernel/Kconfig.locks
+++ b/kernel/Kconfig.locks
@@ -87,6 +87,9 @@ config ARCH_INLINE_WRITE_UNLOCK_IRQ
config ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
bool
+config UNINLINE_SPIN_UNLOCK
+ bool
+
#
# lock_* functions are inlined when:
# - DEBUG_SPINLOCK=n and GENERIC_LOCKBREAK=n and ARCH_INLINE_*LOCK=y
@@ -103,100 +106,120 @@ config ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
# - DEBUG_SPINLOCK=n and ARCH_INLINE_*LOCK=y
#
+if !DEBUG_SPINLOCK
+
config INLINE_SPIN_TRYLOCK
- def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_TRYLOCK
+ def_bool y
+ depends on ARCH_INLINE_SPIN_TRYLOCK
config INLINE_SPIN_TRYLOCK_BH
- def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_TRYLOCK_BH
+ def_bool y
+ depends on ARCH_INLINE_SPIN_TRYLOCK_BH
config INLINE_SPIN_LOCK
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK
config INLINE_SPIN_LOCK_BH
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \
- ARCH_INLINE_SPIN_LOCK_BH
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_BH
config INLINE_SPIN_LOCK_IRQ
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \
- ARCH_INLINE_SPIN_LOCK_IRQ
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_IRQ
config INLINE_SPIN_LOCK_IRQSAVE
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \
- ARCH_INLINE_SPIN_LOCK_IRQSAVE
-
-config UNINLINE_SPIN_UNLOCK
- bool
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_SPIN_LOCK_IRQSAVE
config INLINE_SPIN_UNLOCK_BH
- def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_UNLOCK_BH
+ def_bool y
+ depends on ARCH_INLINE_SPIN_UNLOCK_BH
config INLINE_SPIN_UNLOCK_IRQ
- def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_SPIN_UNLOCK_BH)
+ def_bool y
+ depends on !PREEMPT || ARCH_INLINE_SPIN_UNLOCK_BH
config INLINE_SPIN_UNLOCK_IRQRESTORE
- def_bool !DEBUG_SPINLOCK && ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
+ def_bool y
+ depends on ARCH_INLINE_SPIN_UNLOCK_IRQRESTORE
config INLINE_READ_TRYLOCK
- def_bool !DEBUG_SPINLOCK && ARCH_INLINE_READ_TRYLOCK
+ def_bool y
+ depends on ARCH_INLINE_READ_TRYLOCK
config INLINE_READ_LOCK
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK
config INLINE_READ_LOCK_BH
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \
- ARCH_INLINE_READ_LOCK_BH
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_BH
config INLINE_READ_LOCK_IRQ
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \
- ARCH_INLINE_READ_LOCK_IRQ
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_IRQ
config INLINE_READ_LOCK_IRQSAVE
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \
- ARCH_INLINE_READ_LOCK_IRQSAVE
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_READ_LOCK_IRQSAVE
config INLINE_READ_UNLOCK
- def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_READ_UNLOCK)
+ def_bool y
+ depends on !PREEMPT || ARCH_INLINE_READ_UNLOCK
config INLINE_READ_UNLOCK_BH
- def_bool !DEBUG_SPINLOCK && ARCH_INLINE_READ_UNLOCK_BH
+ def_bool y
+ depends on ARCH_INLINE_READ_UNLOCK_BH
config INLINE_READ_UNLOCK_IRQ
- def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_READ_UNLOCK_BH)
+ def_bool y
+ depends on !PREEMPT || ARCH_INLINE_READ_UNLOCK_BH
config INLINE_READ_UNLOCK_IRQRESTORE
- def_bool !DEBUG_SPINLOCK && ARCH_INLINE_READ_UNLOCK_IRQRESTORE
+ def_bool y
+ depends on ARCH_INLINE_READ_UNLOCK_IRQRESTORE
config INLINE_WRITE_TRYLOCK
- def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_TRYLOCK
+ def_bool y
+ depends on ARCH_INLINE_WRITE_TRYLOCK
config INLINE_WRITE_LOCK
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK
config INLINE_WRITE_LOCK_BH
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \
- ARCH_INLINE_WRITE_LOCK_BH
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_BH
config INLINE_WRITE_LOCK_IRQ
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \
- ARCH_INLINE_WRITE_LOCK_IRQ
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_IRQ
config INLINE_WRITE_LOCK_IRQSAVE
- def_bool !DEBUG_SPINLOCK && !GENERIC_LOCKBREAK && \
- ARCH_INLINE_WRITE_LOCK_IRQSAVE
+ def_bool y
+ depends on !GENERIC_LOCKBREAK && ARCH_INLINE_WRITE_LOCK_IRQSAVE
config INLINE_WRITE_UNLOCK
- def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_WRITE_UNLOCK)
+ def_bool y
+ depends on !PREEMPT || ARCH_INLINE_WRITE_UNLOCK
config INLINE_WRITE_UNLOCK_BH
- def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_UNLOCK_BH
+ def_bool y
+ depends on ARCH_INLINE_WRITE_UNLOCK_BH
config INLINE_WRITE_UNLOCK_IRQ
- def_bool !DEBUG_SPINLOCK && (!PREEMPT || ARCH_INLINE_WRITE_UNLOCK_BH)
+ def_bool y
+ depends on !PREEMPT || ARCH_INLINE_WRITE_UNLOCK_BH
config INLINE_WRITE_UNLOCK_IRQRESTORE
- def_bool !DEBUG_SPINLOCK && ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
+ def_bool y
+ depends on ARCH_INLINE_WRITE_UNLOCK_IRQRESTORE
+
+endif
config MUTEX_SPIN_ON_OWNER
- def_bool SMP && !DEBUG_MUTEXES
+ def_bool y
+ depends on SMP && !DEBUG_MUTEXES