From b351d164e860d1ffffdc501c32f55dd1446c385b Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Thu, 11 Oct 2007 22:11:12 +0200
Subject: [PATCH] lockdep: syscall exit check
Provide a check to validate that we do not hold any locks when switching
back to user-space.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
include/linux/lockdep.h | 2 ++
kernel/lockdep.c | 16 ++++++++++++++++
2 files changed, 18 insertions(+)
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 0e843bf65877..9dc46db2985e 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -238,6 +238,7 @@ extern void lockdep_info(void);
extern void lockdep_reset(void);
extern void lockdep_reset_lock(struct lockdep_map *lock);
extern void lockdep_free_key_range(void *start, unsigned long size);
+extern void lockdep_sys_exit(void);
extern void lockdep_off(void);
extern void lockdep_on(void);
@@ -317,6 +318,7 @@ static inline void lockdep_on(void)
# define INIT_LOCKDEP
# define lockdep_reset() do { debug_locks = 1; } while (0)
# define lockdep_free_key_range(start, size) do { } while (0)
+# define lockdep_sys_exit() do { } while (0)
/*
* The class key takes no space if lockdep is disabled:
*/
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 42ae4a5ab4dc..a6f1ee9c92d9 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -3199,3 +3199,19 @@ void debug_show_held_locks(struct task_struct *task)
}
EXPORT_SYMBOL_GPL(debug_show_held_locks);
+
+void lockdep_sys_exit(void)
+{
+ struct task_struct *curr = current;
+
+ if (unlikely(curr->lockdep_depth)) {
+ if (!debug_locks_off())
+ return;
+ printk("\n================================================\n");
+ printk( "[ BUG: lock held when returning to user space! ]\n");
+ printk( "------------------------------------------------\n");
+ printk("%s/%d is leaving the kernel with locks still held!\n",
+ curr->comm, curr->pid);
+ lockdep_print_held_locks(curr);
+ }
+}
--
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