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authorLinus Torvalds <torvalds@linux-foundation.org>2012-01-14 18:11:11 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-14 18:11:11 -0800
commit892d208bcf79e4e1058707786a7b6d486697cd78 (patch)
tree15446e4d19f7f98078344ab0bc37ae6af4898c6d
parentdca88ad6915b65f6e037f8c3e632fcd92a70bd88 (diff)
parent029aeff5db879afd7760f11214b6fea45f76b58e (diff)
downloadlinux-892d208bcf79e4e1058707786a7b6d486697cd78.tar.gz
Merge tag 'kmemleak' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux
Kmemleak patches Main features: - Handle percpu memory allocations (only scanning them, not actually reporting). - Memory hotplug support. Usability improvements: - Show the origin of early allocations. - Report previously found leaks even if kmemleak has been disabled by some error. * tag 'kmemleak' of git://git.kernel.org/pub/scm/linux/kernel/git/cmarinas/linux: kmemleak: Add support for memory hotplug kmemleak: Handle percpu memory allocation kmemleak: Report previously found leaks even after an error kmemleak: When the early log buffer is exceeded, report the actual number kmemleak: Show where early_log issues come from
-rw-r--r--Documentation/kmemleak.txt3
-rw-r--r--include/linux/kmemleak.h8
-rw-r--r--lib/Kconfig.debug2
-rw-r--r--mm/kmemleak.c158
-rw-r--r--mm/percpu.c12
5 files changed, 155 insertions, 28 deletions
diff --git a/Documentation/kmemleak.txt b/Documentation/kmemleak.txt
index 51063e681ca..b6e39739a36 100644
--- a/Documentation/kmemleak.txt
+++ b/Documentation/kmemleak.txt
@@ -127,7 +127,10 @@ See the include/linux/kmemleak.h header for the functions prototype.
kmemleak_init - initialize kmemleak
kmemleak_alloc - notify of a memory block allocation
+kmemleak_alloc_percpu - notify of a percpu memory block allocation
kmemleak_free - notify of a memory block freeing
+kmemleak_free_part - notify of a partial memory block freeing
+kmemleak_free_percpu - notify of a percpu memory block freeing
kmemleak_not_leak - mark an object as not a leak
kmemleak_ignore - do not scan or report an object as leak
kmemleak_scan_area - add scan areas inside a memory block
diff --git a/include/linux/kmemleak.h b/include/linux/kmemleak.h
index 99d9a6766f7..2a5e5548a1d 100644
--- a/include/linux/kmemleak.h
+++ b/include/linux/kmemleak.h
@@ -26,8 +26,10 @@
extern void kmemleak_init(void) __ref;
extern void kmemleak_alloc(const void *ptr, size_t size, int min_count,
gfp_t gfp) __ref;
+extern void kmemleak_alloc_percpu(const void __percpu *ptr, size_t size) __ref;
extern void kmemleak_free(const void *ptr) __ref;
extern void kmemleak_free_part(const void *ptr, size_t size) __ref;
+extern void kmemleak_free_percpu(const void __percpu *ptr) __ref;
extern void kmemleak_padding(const void *ptr, unsigned long offset,
size_t size) __ref;
extern void kmemleak_not_leak(const void *ptr) __ref;
@@ -68,6 +70,9 @@ static inline void kmemleak_alloc_recursive(const void *ptr, size_t size,
gfp_t gfp)
{
}
+static inline void kmemleak_alloc_percpu(const void __percpu *ptr, size_t size)
+{
+}
static inline void kmemleak_free(const void *ptr)
{
}
@@ -77,6 +82,9 @@ static inline void kmemleak_free_part(const void *ptr, size_t size)
static inline void kmemleak_free_recursive(const void *ptr, unsigned long flags)
{
}
+static inline void kmemleak_free_percpu(const void __percpu *ptr)
+{
+}
static inline void kmemleak_not_leak(const void *ptr)
{
}
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 82928f5ea04..8745ac7d1f7 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -414,7 +414,7 @@ config SLUB_STATS
config DEBUG_KMEMLEAK
bool "Kernel memory leak detector"
- depends on DEBUG_KERNEL && EXPERIMENTAL && !MEMORY_HOTPLUG && \
+ depends on DEBUG_KERNEL && EXPERIMENTAL && \
(X86 || ARM || PPC || MIPS || S390 || SPARC64 || SUPERH || MICROBLAZE || TILE)
select DEBUG_FS
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index f3b2a00fe9c..c833addd94d 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -100,6 +100,7 @@
#include <linux/kmemcheck.h>
#include <linux/kmemleak.h>
+#include <linux/memory_hotplug.h>
/*
* Kmemleak configuration and common defines.
@@ -196,7 +197,9 @@ static atomic_t kmemleak_enabled = ATOMIC_INIT(0);
static atomic_t kmemleak_initialized = ATOMIC_INIT(0);
/* enables or disables early logging of the memory operations */
static atomic_t kmemleak_early_log = ATOMIC_INIT(1);
-/* set if a fata kmemleak error has occurred */
+/* set if a kmemleak warning was issued */
+static atomic_t kmemleak_warning = ATOMIC_INIT(0);
+/* set if a fatal kmemleak error has occurred */
static atomic_t kmemleak_error = ATOMIC_INIT(0);
/* minimum and maximum address that may be valid pointers */
@@ -228,8 +231,10 @@ static int kmemleak_skip_disable;
/* kmemleak operation type for early logging */
enum {
KMEMLEAK_ALLOC,
+ KMEMLEAK_ALLOC_PERCPU,
KMEMLEAK_FREE,
KMEMLEAK_FREE_PART,
+ KMEMLEAK_FREE_PERCPU,
KMEMLEAK_NOT_LEAK,
KMEMLEAK_IGNORE,
KMEMLEAK_SCAN_AREA,
@@ -259,9 +264,10 @@ static void kmemleak_disable(void);
/*
* Print a warning and dump the stack trace.
*/
-#define kmemleak_warn(x...) do { \
- pr_warning(x); \
- dump_stack(); \
+#define kmemleak_warn(x...) do { \
+ pr_warning(x); \
+ dump_stack(); \
+ atomic_set(&kmemleak_warning, 1); \
} while (0)
/*
@@ -403,8 +409,8 @@ static struct kmemleak_object *lookup_object(unsigned long ptr, int alias)
object = prio_tree_entry(node, struct kmemleak_object,
tree_node);
if (!alias && object->pointer != ptr) {
- pr_warning("Found object by alias at 0x%08lx\n", ptr);
- dump_stack();
+ kmemleak_warn("Found object by alias at 0x%08lx\n",
+ ptr);
dump_object_info(object);
object = NULL;
}
@@ -794,9 +800,13 @@ static void __init log_early(int op_type, const void *ptr, size_t size,
unsigned long flags;
struct early_log *log;
+ if (atomic_read(&kmemleak_error)) {
+ /* kmemleak stopped recording, just count the requests */
+ crt_early_log++;
+ return;
+ }
+
if (crt_early_log >= ARRAY_SIZE(early_log)) {
- pr_warning("Early log buffer exceeded, "
- "please increase DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n");
kmemleak_disable();
return;
}
@@ -811,8 +821,7 @@ static void __init log_early(int op_type, const void *ptr, size_t size,
log->ptr = ptr;
log->size = size;
log->min_count = min_count;
- if (op_type == KMEMLEAK_ALLOC)
- log->trace_len = __save_stack_trace(log->trace);
+ log->trace_len = __save_stack_trace(log->trace);
crt_early_log++;
local_irq_restore(flags);
}
@@ -846,6 +855,20 @@ out:
rcu_read_unlock();
}
+/*
+ * Log an early allocated block and populate the stack trace.
+ */
+static void early_alloc_percpu(struct early_log *log)
+{
+ unsigned int cpu;
+ const void __percpu *ptr = log->ptr;
+
+ for_each_possible_cpu(cpu) {
+ log->ptr = per_cpu_ptr(ptr, cpu);
+ early_alloc(log);
+ }
+}
+
/**
* kmemleak_alloc - register a newly allocated object
* @ptr: pointer to beginning of the object
@@ -873,6 +896,34 @@ void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
EXPORT_SYMBOL_GPL(kmemleak_alloc);
/**
+ * kmemleak_alloc_percpu - register a newly allocated __percpu object
+ * @ptr: __percpu pointer to beginning of the object
+ * @size: size of the object
+ *
+ * This function is called from the kernel percpu allocator when a new object
+ * (memory block) is allocated (alloc_percpu). It assumes GFP_KERNEL
+ * allocation.
+ */
+void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size)
+{
+ unsigned int cpu;
+
+ pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
+
+ /*
+ * Percpu allocations are only scanned and not reported as leaks
+ * (min_count is set to 0).
+ */
+ if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
+ for_each_possible_cpu(cpu)
+ create_object((unsigned long)per_cpu_ptr(ptr, cpu),
+ size, 0, GFP_KERNEL);
+ else if (atomic_read(&kmemleak_early_log))
+ log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
+}
+EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
+
+/**
* kmemleak_free - unregister a previously registered object
* @ptr: pointer to beginning of the object
*
@@ -911,6 +962,28 @@ void __ref kmemleak_free_part(const void *ptr, size_t size)
EXPORT_SYMBOL_GPL(kmemleak_free_part);
/**
+ * kmemleak_free_percpu - unregister a previously registered __percpu object
+ * @ptr: __percpu pointer to beginning of the object
+ *
+ * This function is called from the kernel percpu allocator when an object
+ * (memory block) is freed (free_percpu).
+ */
+void __ref kmemleak_free_percpu(const void __percpu *ptr)
+{
+ unsigned int cpu;
+
+ pr_debug("%s(0x%p)\n", __func__, ptr);
+
+ if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
+ for_each_possible_cpu(cpu)
+ delete_object_full((unsigned long)per_cpu_ptr(ptr,
+ cpu));
+ else if (atomic_read(&kmemleak_early_log))
+ log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
+}
+EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
+
+/**
* kmemleak_not_leak - mark an allocated object as false positive
* @ptr: pointer to beginning of the object
*
@@ -1220,9 +1293,9 @@ static void kmemleak_scan(void)
#endif
/*
- * Struct page scanning for each node. The code below is not yet safe
- * with MEMORY_HOTPLUG.
+ * Struct page scanning for each node.
*/
+ lock_memory_hotplug();
for_each_online_node(i) {
pg_data_t *pgdat = NODE_DATA(i);
unsigned long start_pfn = pgdat->node_start_pfn;
@@ -1241,6 +1314,7 @@ static void kmemleak_scan(void)
scan_block(page, page + 1, NULL, 1);
}
}
+ unlock_memory_hotplug();
/*
* Scanning the task stacks (may introduce false negatives).
@@ -1467,9 +1541,6 @@ static const struct seq_operations kmemleak_seq_ops = {
static int kmemleak_open(struct inode *inode, struct file *file)
{
- if (!atomic_read(&kmemleak_enabled))
- return -EBUSY;
-
return seq_open(file, &kmemleak_seq_ops);
}
@@ -1543,6 +1614,9 @@ static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
int buf_size;
int ret;
+ if (!atomic_read(&kmemleak_enabled))
+ return -EBUSY;
+
buf_size = min(size, (sizeof(buf) - 1));
if (strncpy_from_user(buf, user_buf, buf_size) < 0)
return -EFAULT;
@@ -1602,20 +1676,24 @@ static const struct file_operations kmemleak_fops = {
};
/*
- * Perform the freeing of the kmemleak internal objects after waiting for any
- * current memory scan to complete.
+ * Stop the memory scanning thread and free the kmemleak internal objects if
+ * no previous scan thread (otherwise, kmemleak may still have some useful
+ * information on memory leaks).
*/
static void kmemleak_do_cleanup(struct work_struct *work)
{
struct kmemleak_object *object;
+ bool cleanup = scan_thread == NULL;
mutex_lock(&scan_mutex);
stop_scan_thread();
- rcu_read_lock();
- list_for_each_entry_rcu(object, &object_list, object_list)
- delete_object_full(object->pointer);
- rcu_read_unlock();
+ if (cleanup) {
+ rcu_read_lock();
+ list_for_each_entry_rcu(object, &object_list, object_list)
+ delete_object_full(object->pointer);
+ rcu_read_unlock();
+ }
mutex_unlock(&scan_mutex);
}
@@ -1632,7 +1710,6 @@ static void kmemleak_disable(void)
return;
/* stop any memory operation tracing */
- atomic_set(&kmemleak_early_log, 0);
atomic_set(&kmemleak_enabled, 0);
/* check whether it is too early for a kernel thread */
@@ -1659,6 +1736,17 @@ static int kmemleak_boot_config(char *str)
}
early_param("kmemleak", kmemleak_boot_config);
+static void __init print_log_trace(struct early_log *log)
+{
+ struct stack_trace trace;
+
+ trace.nr_entries = log->trace_len;
+ trace.entries = log->trace;
+
+ pr_notice("Early log backtrace:\n");
+ print_stack_trace(&trace, 2);
+}
+
/*
* Kmemleak initialization.
*/
@@ -1681,12 +1769,18 @@ void __init kmemleak_init(void)
scan_area_cache = KMEM_CACHE(kmemleak_scan_area, SLAB_NOLEAKTRACE);
INIT_PRIO_TREE_ROOT(&object_tree_root);
+ if (crt_early_log >= ARRAY_SIZE(early_log))
+ pr_warning("Early log buffer exceeded (%d), please increase "
+ "DEBUG_KMEMLEAK_EARLY_LOG_SIZE\n", crt_early_log);
+
/* the kernel is still in UP mode, so disabling the IRQs is enough */
local_irq_save(flags);
- if (!atomic_read(&kmemleak_error)) {
+ atomic_set(&kmemleak_early_log, 0);
+ if (atomic_read(&kmemleak_error)) {
+ local_irq_restore(flags);
+ return;
+ } else
atomic_set(&kmemleak_enabled, 1);
- atomic_set(&kmemleak_early_log, 0);
- }
local_irq_restore(flags);
/*
@@ -1701,12 +1795,18 @@ void __init kmemleak_init(void)
case KMEMLEAK_ALLOC:
early_alloc(log);
break;
+ case KMEMLEAK_ALLOC_PERCPU:
+ early_alloc_percpu(log);
+ break;
case KMEMLEAK_FREE:
kmemleak_free(log->ptr);
break;
case KMEMLEAK_FREE_PART:
kmemleak_free_part(log->ptr, log->size);
break;
+ case KMEMLEAK_FREE_PERCPU:
+ kmemleak_free_percpu(log->ptr);
+ break;
case KMEMLEAK_NOT_LEAK:
kmemleak_not_leak(log->ptr);
break;
@@ -1720,7 +1820,13 @@ void __init kmemleak_init(void)
kmemleak_no_scan(log->ptr);
break;
default:
- WARN_ON(1);
+ kmemleak_warn("Unknown early log operation: %d\n",
+ log->op_type);
+ }
+
+ if (atomic_read(&kmemleak_warning)) {
+ print_log_trace(log);
+ atomic_set(&kmemleak_warning, 0);
}
}
}
diff --git a/mm/percpu.c b/mm/percpu.c
index 716eb4acf2f..f47af9123af 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -67,6 +67,7 @@
#include <linux/spinlock.h>
#include <linux/vmalloc.h>
#include <linux/workqueue.h>
+#include <linux/kmemleak.h>
#include <asm/cacheflush.h>
#include <asm/sections.h>
@@ -710,6 +711,7 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved)
const char *err;
int slot, off, new_alloc;
unsigned long flags;
+ void __percpu *ptr;
if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) {
WARN(true, "illegal size (%zu) or align (%zu) for "
@@ -802,7 +804,9 @@ area_found:
mutex_unlock(&pcpu_alloc_mutex);
/* return address relative to base address */
- return __addr_to_pcpu_ptr(chunk->base_addr + off);
+ ptr = __addr_to_pcpu_ptr(chunk->base_addr + off);
+ kmemleak_alloc_percpu(ptr, size);
+ return ptr;
fail_unlock:
spin_unlock_irqrestore(&pcpu_lock, flags);
@@ -916,6 +920,8 @@ void free_percpu(void __percpu *ptr)
if (!ptr)
return;
+ kmemleak_free_percpu(ptr);
+
addr = __pcpu_ptr_to_addr(ptr);
spin_lock_irqsave(&pcpu_lock, flags);
@@ -1639,6 +1645,8 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
rc = -ENOMEM;
goto out_free_areas;
}
+ /* kmemleak tracks the percpu allocations separately */
+ kmemleak_free(ptr);
areas[group] = ptr;
base = min(ptr, base);
@@ -1753,6 +1761,8 @@ int __init pcpu_page_first_chunk(size_t reserved_size,
"for cpu%u\n", psize_str, cpu);
goto enomem;
}
+ /* kmemleak tracks the percpu allocations separately */
+ kmemleak_free(ptr);
pages[j++] = virt_to_page(ptr);
}