[patch 8/8] mutex subsystem, more debugging code

[Ingo Molnar <mingo@elte.hu>]

more mutex debugging: check for held locks during memory freeing,
task exit, enable sysrq printouts, etc.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

----

 arch/i386/mm/pageattr.c |    4 ++++
 drivers/char/sysrq.c    |   19 +++++++++++++++++++
 include/linux/mm.h      |    4 ++++
 kernel/exit.c           |    5 +++++
 kernel/sched.c          |    1 +
 lib/spinlock_debug.c    |   18 ++++++++++--------
 mm/page_alloc.c         |    3 +++
 mm/slab.c               |    1 +
 8 files changed, 47 insertions(+), 8 deletions(-)

Index: linux/arch/i386/mm/pageattr.c
===================================================================
--- linux.orig/arch/i386/mm/pageattr.c
+++ linux/arch/i386/mm/pageattr.c
@@ -207,6 +207,10 @@ void kernel_map_pages(struct page *page,
 {
 	if (PageHighMem(page))
 		return;
+	if (!enable)
+		mutex_debug_check_no_locks_freed(page_address(page),
+						 page_address(page+numpages));
+
 	/* the return value is ignored - the calls cannot fail,
 	 * large pages are disabled at boot time.
 	 */
Index: linux/drivers/char/sysrq.c
===================================================================
--- linux.orig/drivers/char/sysrq.c
+++ linux/drivers/char/sysrq.c
@@ -153,6 +153,21 @@ static struct sysrq_key_op sysrq_mountro
 
 /* END SYNC SYSRQ HANDLERS BLOCK */
 
+#ifdef CONFIG_DEBUG_MUTEXES
+
+static void
+sysrq_handle_showlocks(int key, struct pt_regs *pt_regs, struct tty_struct *tty)
+{
+	mutex_debug_show_all_locks();
+}
+
+static struct sysrq_key_op sysrq_showlocks_op = {
+	.handler	= sysrq_handle_showlocks,
+	.help_msg	= "show-all-locks(D)",
+	.action_msg	= "Show Locks Held",
+};
+
+#endif
 
 /* SHOW SYSRQ HANDLERS BLOCK */
 
@@ -294,7 +309,11 @@ static struct sysrq_key_op *sysrq_key_ta
 #else
 /* c */	NULL,
 #endif
+#ifdef CONFIG_DEBUG_MUTEXES
+/* d */ &sysrq_showlocks_op,
+#else
 /* d */ NULL,
+#endif
 /* e */	&sysrq_term_op,
 /* f */	&sysrq_moom_op,
 /* g */	NULL,
Index: linux/include/linux/mm.h
===================================================================
--- linux.orig/include/linux/mm.h
+++ linux/include/linux/mm.h
@@ -13,6 +13,7 @@
 #include <linux/rbtree.h>
 #include <linux/prio_tree.h>
 #include <linux/fs.h>
+#include <linux/mutex.h>
 
 struct mempolicy;
 struct anon_vma;
@@ -977,6 +978,9 @@ static inline void vm_stat_account(struc
 static inline void
 kernel_map_pages(struct page *page, int numpages, int enable)
 {
+	if (!PageHighMem(page) && !enable)
+		mutex_debug_check_no_locks_freed(page_address(page),
+						 page_address(page + numpages));
 }
 #endif
 
Index: linux/kernel/exit.c
===================================================================
--- linux.orig/kernel/exit.c
+++ linux/kernel/exit.c
@@ -29,6 +29,7 @@
 #include <linux/syscalls.h>
 #include <linux/signal.h>
 #include <linux/cn_proc.h>
+#include <linux/mutex.h>
 
 #include <asm/uaccess.h>
 #include <asm/unistd.h>
@@ -870,6 +871,10 @@ fastcall NORET_TYPE void do_exit(long co
 	mpol_free(tsk->mempolicy);
 	tsk->mempolicy = NULL;
 #endif
+	/*
+	 * If DEBUG_MUTEXES is on, make sure we are holding no locks:
+	 */
+	mutex_debug_check_no_locks_held(tsk);
 
 	/* PF_DEAD causes final put_task_struct after we schedule. */
 	preempt_disable();
Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c
+++ linux/kernel/sched.c
@@ -4379,6 +4379,7 @@ void show_state(void)
 	} while_each_thread(g, p);
 
 	read_unlock(&tasklist_lock);
+	mutex_debug_show_all_locks();
 }
 
 /**
Index: linux/lib/spinlock_debug.c
===================================================================
--- linux.orig/lib/spinlock_debug.c
+++ linux/lib/spinlock_debug.c
@@ -20,7 +20,8 @@ static void spin_bug(spinlock_t *lock, c
 		if (lock->owner && lock->owner != SPINLOCK_OWNER_INIT)
 			owner = lock->owner;
 		printk("BUG: spinlock %s on CPU#%d, %s/%d\n",
-			msg, smp_processor_id(), current->comm, current->pid);
+			msg, raw_smp_processor_id(),
+			current->comm, current->pid);
 		printk(" lock: %p, .magic: %08x, .owner: %s/%d, .owner_cpu: %d\n",
 			lock, lock->magic,
 			owner ? owner->comm : "<none>",
@@ -78,8 +79,8 @@ static void __spin_lock_debug(spinlock_t
 		if (print_once) {
 			print_once = 0;
 			printk("BUG: spinlock lockup on CPU#%d, %s/%d, %p\n",
-				smp_processor_id(), current->comm, current->pid,
-					lock);
+				raw_smp_processor_id(), current->comm,
+				current->pid, lock);
 			dump_stack();
 		}
 	}
@@ -120,7 +121,8 @@ static void rwlock_bug(rwlock_t *lock, c
 
 	if (xchg(&print_once, 0)) {
 		printk("BUG: rwlock %s on CPU#%d, %s/%d, %p\n", msg,
-			smp_processor_id(), current->comm, current->pid, lock);
+			raw_smp_processor_id(), current->comm,
+			current->pid, lock);
 		dump_stack();
 #ifdef CONFIG_SMP
 		/*
@@ -148,8 +150,8 @@ static void __read_lock_debug(rwlock_t *
 		if (print_once) {
 			print_once = 0;
 			printk("BUG: read-lock lockup on CPU#%d, %s/%d, %p\n",
-				smp_processor_id(), current->comm, current->pid,
-					lock);
+				raw_smp_processor_id(), current->comm,
+				current->pid, lock);
 			dump_stack();
 		}
 	}
@@ -220,8 +222,8 @@ static void __write_lock_debug(rwlock_t 
 		if (print_once) {
 			print_once = 0;
 			printk("BUG: write-lock lockup on CPU#%d, %s/%d, %p\n",
-				smp_processor_id(), current->comm, current->pid,
-					lock);
+				raw_smp_processor_id(), current->comm,
+				current->pid, lock);
 			dump_stack();
 		}
 	}
Index: linux/mm/page_alloc.c
===================================================================
--- linux.orig/mm/page_alloc.c
+++ linux/mm/page_alloc.c
@@ -400,6 +400,9 @@ void __free_pages_ok(struct page *page, 
 	int reserved = 0;
 
 	arch_free_page(page, order);
+	if (!PageHighMem(page))
+		mutex_debug_check_no_locks_freed(page_address(page),
+			page_address(page+(1<<order)));
 
 #ifndef CONFIG_MMU
 	if (order > 0)
Index: linux/mm/slab.c
===================================================================
--- linux.orig/mm/slab.c
+++ linux/mm/slab.c
@@ -3038,6 +3038,7 @@ void kfree(const void *objp)
 	local_irq_save(flags);
 	kfree_debugcheck(objp);
 	c = page_get_cache(virt_to_page(objp));
+	mutex_debug_check_no_locks_freed(objp, objp+obj_reallen(c));
 	__cache_free(c, (void*)objp);
 	local_irq_restore(flags);
 }