[PATCH] mutex subsystem, more debugging code
more mutex debugging: check for held locks during memory freeing,
task exit, enable sysrq printouts, etc.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@infradead.org>
diff --git a/arch/i386/mm/pageattr.c b/arch/i386/mm/pageattr.c
index c30a16d..e8a5355 100644
--- a/arch/i386/mm/pageattr.c
+++ b/arch/i386/mm/pageattr.c
@@ -222,6 +222,10 @@
{
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.
*/
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index 145275e..5765f67 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -153,6 +153,21 @@
/* 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 @@
#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,
diff --git a/include/linux/mm.h b/include/linux/mm.h
index df80e63..3f1fafc 100644
--- a/include/linux/mm.h
+++ b/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;
@@ -1024,6 +1025,9 @@
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
diff --git a/kernel/exit.c b/kernel/exit.c
index caceabf..309a46f 100644
--- a/kernel/exit.c
+++ b/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>
@@ -869,6 +870,10 @@
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();
diff --git a/kernel/sched.c b/kernel/sched.c
index 9273309..34a945b 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -4386,6 +4386,7 @@
} while_each_thread(g, p);
read_unlock(&tasklist_lock);
+ mutex_debug_show_all_locks();
}
/**
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e0e8492..a5e6891 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -415,6 +415,9 @@
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
for (i = 1 ; i < (1 << order) ; ++i)
diff --git a/mm/slab.c b/mm/slab.c
index 1c46c63..33aab34 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3071,6 +3071,7 @@
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);
}