* [PATCH v4 2/4] kmemleak: allow freeing internal objects after kmemleak was disabled
2014-03-28 10:50 [PATCH v4 1/4] kmemleak: free internal objects only if there're no leaks to be reported Li Zefan
@ 2014-03-28 10:50 ` Li Zefan
2014-03-28 10:50 ` [PATCH v4 3/4] kmemleak: remove redundant code Li Zefan
2014-03-28 10:51 ` [PATCH v4 4/4] kmemleak: change some global variables to int Li Zefan
2 siblings, 0 replies; 4+ messages in thread
From: Li Zefan @ 2014-03-28 10:50 UTC (permalink / raw)
To: Andrew Morton; +Cc: Catalin Marinas, LKML, Cgroups
Currently if kmemleak is disabled, the kmemleak objects can never be
freed, no matter if it's disabled by a user or due to fatal errors.
Those objects can be a big waste of memory.
OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME
1200264 1197433 99% 0.30K 46164 26 369312K kmemleak_object
With this patch, after kmemleak was disabled you can reclaim memory with:
# echo clear > /sys/kernel/debug/kmemleak
Also inform users about this with a printk.
v4: rephrase the printk string.
v3: Catalin wasn't suggesting to use "off" handler, but he wants to be
able to read memory leaks even when kmemleak is explicitly disabled.
v2: use "off" handler instead of "clear" handler to do this, suggested
by Catalin.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
---
Documentation/kmemleak.txt | 15 ++++++++++++++-
mm/kmemleak.c | 46 ++++++++++++++++++++++++++++++++--------------
2 files changed, 46 insertions(+), 15 deletions(-)
diff --git a/Documentation/kmemleak.txt b/Documentation/kmemleak.txt
index 6dc8013..a7563ec 100644
--- a/Documentation/kmemleak.txt
+++ b/Documentation/kmemleak.txt
@@ -51,7 +51,8 @@ Memory scanning parameters can be modified at run-time by writing to the
(default 600, 0 to stop the automatic scanning)
scan - trigger a memory scan
clear - clear list of current memory leak suspects, done by
- marking all current reported unreferenced objects grey
+ marking all current reported unreferenced objects grey,
+ or free all kmemleak objects if kmemleak has been disabled.
dump=<addr> - dump information about the object found at <addr>
Kmemleak can also be disabled at boot-time by passing "kmemleak=off" on
@@ -118,6 +119,18 @@ Then as usual to get your report with:
# cat /sys/kernel/debug/kmemleak
+Freeing kmemleak internal objects
+---------------------------------
+
+To allow access to previosuly found memory leaks after kmemleak has been
+disabled by the user or due to an fatal error, internal kmemleak objects
+won't be freed when kmemleak is disabled, and those objects may occupy
+a large part of physical memory.
+
+In this situation, you may reclaim memory with:
+
+ # echo clear > /sys/kernel/debug/kmemleak
+
Kmemleak API
------------
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 474379e..06cd220 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1600,6 +1600,8 @@ static void kmemleak_clear(void)
kmemleak_found_leaks = false;
}
+static void __kmemleak_do_cleanup(void);
+
/*
* File write operation to configure kmemleak at run-time. The following
* commands can be written to the /sys/kernel/debug/kmemleak file:
@@ -1612,7 +1614,8 @@ static void kmemleak_clear(void)
* disable it)
* scan - trigger a memory scan
* clear - mark all current reported unreferenced kmemleak objects as
- * grey to ignore printing them
+ * grey to ignore printing them, or free all kmemleak objects
+ * if kmemleak has been disabled.
* dump=... - dump information about the object found at the given address
*/
static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
@@ -1622,9 +1625,6 @@ 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;
@@ -1634,6 +1634,19 @@ static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
if (ret < 0)
return ret;
+ if (strncmp(buf, "clear", 5) == 0) {
+ if (atomic_read(&kmemleak_enabled))
+ kmemleak_clear();
+ else
+ __kmemleak_do_cleanup();
+ goto out;
+ }
+
+ if (!atomic_read(&kmemleak_enabled)) {
+ ret = -EBUSY;
+ goto out;
+ }
+
if (strncmp(buf, "off", 3) == 0)
kmemleak_disable();
else if (strncmp(buf, "stack=on", 8) == 0)
@@ -1657,8 +1670,6 @@ static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
}
} else if (strncmp(buf, "scan", 4) == 0)
kmemleak_scan();
- else if (strncmp(buf, "clear", 5) == 0)
- kmemleak_clear();
else if (strncmp(buf, "dump=", 5) == 0)
ret = dump_str_object_info(buf + 5);
else
@@ -1683,6 +1694,16 @@ static const struct file_operations kmemleak_fops = {
.release = kmemleak_release,
};
+static void __kmemleak_do_cleanup(void)
+{
+ struct kmemleak_object *object;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(object, &object_list, object_list)
+ delete_object_full(object->pointer);
+ rcu_read_unlock();
+}
+
/*
* Stop the memory scanning thread and free the kmemleak internal objects if
* no previous scan thread (otherwise, kmemleak may still have some useful
@@ -1690,17 +1711,14 @@ static const struct file_operations kmemleak_fops = {
*/
static void kmemleak_do_cleanup(struct work_struct *work)
{
- struct kmemleak_object *object;
-
mutex_lock(&scan_mutex);
stop_scan_thread();
- if (!kmemleak_found_leaks) {
- rcu_read_lock();
- list_for_each_entry_rcu(object, &object_list, object_list)
- delete_object_full(object->pointer);
- rcu_read_unlock();
- }
+ if (!kmemleak_found_leaks)
+ __kmemleak_do_cleanup();
+ else
+ pr_info("Kmemleak disabled without freeing internal data. "
+ "Reclaim the memory with \"echo clear > /sys/kernel/debug/kmemleak\"\n");
mutex_unlock(&scan_mutex);
}
--
1.8.0.2
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v4 4/4] kmemleak: change some global variables to int
2014-03-28 10:50 [PATCH v4 1/4] kmemleak: free internal objects only if there're no leaks to be reported Li Zefan
2014-03-28 10:50 ` [PATCH v4 2/4] kmemleak: allow freeing internal objects after kmemleak was disabled Li Zefan
2014-03-28 10:50 ` [PATCH v4 3/4] kmemleak: remove redundant code Li Zefan
@ 2014-03-28 10:51 ` Li Zefan
2 siblings, 0 replies; 4+ messages in thread
From: Li Zefan @ 2014-03-28 10:51 UTC (permalink / raw)
To: Andrew Morton; +Cc: Catalin Marinas, LKML, Cgroups
They don't have to be atomic_t, because they are simple boolean
toggles.
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
---
mm/kmemleak.c | 80 +++++++++++++++++++++++++++++------------------------------
1 file changed, 40 insertions(+), 40 deletions(-)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 6f90d00..91d67ea 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -192,15 +192,15 @@ static struct kmem_cache *object_cache;
static struct kmem_cache *scan_area_cache;
/* set if tracing memory operations is enabled */
-static atomic_t kmemleak_enabled = ATOMIC_INIT(0);
+static int kmemleak_enabled;
/* set in the late_initcall if there were no errors */
-static atomic_t kmemleak_initialized = ATOMIC_INIT(0);
+static int kmemleak_initialized;
/* enables or disables early logging of the memory operations */
-static atomic_t kmemleak_early_log = ATOMIC_INIT(1);
+static int kmemleak_early_log = 1;
/* set if a kmemleak warning was issued */
-static atomic_t kmemleak_warning = ATOMIC_INIT(0);
+static int kmemleak_warning;
/* set if a fatal kmemleak error has occurred */
-static atomic_t kmemleak_error = ATOMIC_INIT(0);
+static int kmemleak_error;
/* minimum and maximum address that may be valid pointers */
static unsigned long min_addr = ULONG_MAX;
@@ -268,7 +268,7 @@ static void kmemleak_disable(void);
#define kmemleak_warn(x...) do { \
pr_warning(x); \
dump_stack(); \
- atomic_set(&kmemleak_warning, 1); \
+ kmemleak_warning = 1; \
} while (0)
/*
@@ -806,7 +806,7 @@ 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)) {
+ if (kmemleak_error) {
/* kmemleak stopped recording, just count the requests */
crt_early_log++;
return;
@@ -841,7 +841,7 @@ static void early_alloc(struct early_log *log)
unsigned long flags;
int i;
- if (!atomic_read(&kmemleak_enabled) || !log->ptr || IS_ERR(log->ptr))
+ if (!kmemleak_enabled || !log->ptr || IS_ERR(log->ptr))
return;
/*
@@ -894,9 +894,9 @@ void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
{
pr_debug("%s(0x%p, %zu, %d)\n", __func__, ptr, size, min_count);
- if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
+ if (kmemleak_enabled && ptr && !IS_ERR(ptr))
create_object((unsigned long)ptr, size, min_count, gfp);
- else if (atomic_read(&kmemleak_early_log))
+ else if (kmemleak_early_log)
log_early(KMEMLEAK_ALLOC, ptr, size, min_count);
}
EXPORT_SYMBOL_GPL(kmemleak_alloc);
@@ -920,11 +920,11 @@ void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t 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))
+ if (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))
+ else if (kmemleak_early_log)
log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
}
EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
@@ -940,9 +940,9 @@ void __ref kmemleak_free(const void *ptr)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
- if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
+ if (kmemleak_enabled && ptr && !IS_ERR(ptr))
delete_object_full((unsigned long)ptr);
- else if (atomic_read(&kmemleak_early_log))
+ else if (kmemleak_early_log)
log_early(KMEMLEAK_FREE, ptr, 0, 0);
}
EXPORT_SYMBOL_GPL(kmemleak_free);
@@ -960,9 +960,9 @@ void __ref kmemleak_free_part(const void *ptr, size_t size)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
- if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
+ if (kmemleak_enabled && ptr && !IS_ERR(ptr))
delete_object_part((unsigned long)ptr, size);
- else if (atomic_read(&kmemleak_early_log))
+ else if (kmemleak_early_log)
log_early(KMEMLEAK_FREE_PART, ptr, size, 0);
}
EXPORT_SYMBOL_GPL(kmemleak_free_part);
@@ -980,11 +980,11 @@ void __ref kmemleak_free_percpu(const void __percpu *ptr)
pr_debug("%s(0x%p)\n", __func__, ptr);
- if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
+ if (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))
+ else if (kmemleak_early_log)
log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
}
EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
@@ -1000,9 +1000,9 @@ void __ref kmemleak_not_leak(const void *ptr)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
- if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
+ if (kmemleak_enabled && ptr && !IS_ERR(ptr))
make_gray_object((unsigned long)ptr);
- else if (atomic_read(&kmemleak_early_log))
+ else if (kmemleak_early_log)
log_early(KMEMLEAK_NOT_LEAK, ptr, 0, 0);
}
EXPORT_SYMBOL(kmemleak_not_leak);
@@ -1020,9 +1020,9 @@ void __ref kmemleak_ignore(const void *ptr)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
- if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
+ if (kmemleak_enabled && ptr && !IS_ERR(ptr))
make_black_object((unsigned long)ptr);
- else if (atomic_read(&kmemleak_early_log))
+ else if (kmemleak_early_log)
log_early(KMEMLEAK_IGNORE, ptr, 0, 0);
}
EXPORT_SYMBOL(kmemleak_ignore);
@@ -1042,9 +1042,9 @@ void __ref kmemleak_scan_area(const void *ptr, size_t size, gfp_t gfp)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
- if (atomic_read(&kmemleak_enabled) && ptr && size && !IS_ERR(ptr))
+ if (kmemleak_enabled && ptr && size && !IS_ERR(ptr))
add_scan_area((unsigned long)ptr, size, gfp);
- else if (atomic_read(&kmemleak_early_log))
+ else if (kmemleak_early_log)
log_early(KMEMLEAK_SCAN_AREA, ptr, size, 0);
}
EXPORT_SYMBOL(kmemleak_scan_area);
@@ -1062,9 +1062,9 @@ void __ref kmemleak_no_scan(const void *ptr)
{
pr_debug("%s(0x%p)\n", __func__, ptr);
- if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
+ if (kmemleak_enabled && ptr && !IS_ERR(ptr))
object_no_scan((unsigned long)ptr);
- else if (atomic_read(&kmemleak_early_log))
+ else if (kmemleak_early_log)
log_early(KMEMLEAK_NO_SCAN, ptr, 0, 0);
}
EXPORT_SYMBOL(kmemleak_no_scan);
@@ -1089,7 +1089,7 @@ static bool update_checksum(struct kmemleak_object *object)
*/
static int scan_should_stop(void)
{
- if (!atomic_read(&kmemleak_enabled))
+ if (!kmemleak_enabled)
return 1;
/*
@@ -1630,14 +1630,14 @@ static ssize_t kmemleak_write(struct file *file, const char __user *user_buf,
return ret;
if (strncmp(buf, "clear", 5) == 0) {
- if (atomic_read(&kmemleak_enabled))
+ if (kmemleak_enabled)
kmemleak_clear();
else
__kmemleak_do_cleanup();
goto out;
}
- if (!atomic_read(&kmemleak_enabled)) {
+ if (!kmemleak_enabled) {
ret = -EBUSY;
goto out;
}
@@ -1726,14 +1726,14 @@ static DECLARE_WORK(cleanup_work, kmemleak_do_cleanup);
static void kmemleak_disable(void)
{
/* atomically check whether it was already invoked */
- if (atomic_cmpxchg(&kmemleak_error, 0, 1))
+ if (cmpxchg(&kmemleak_error, 0, 1))
return;
/* stop any memory operation tracing */
- atomic_set(&kmemleak_enabled, 0);
+ kmemleak_enabled = 0;
/* check whether it is too early for a kernel thread */
- if (atomic_read(&kmemleak_initialized))
+ if (kmemleak_initialized)
schedule_work(&cleanup_work);
pr_info("Kernel memory leak detector disabled\n");
@@ -1775,9 +1775,10 @@ void __init kmemleak_init(void)
int i;
unsigned long flags;
+ kmemleak_early_log = 0;
+
#ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
if (!kmemleak_skip_disable) {
- atomic_set(&kmemleak_early_log, 0);
kmemleak_disable();
return;
}
@@ -1795,12 +1796,11 @@ void __init kmemleak_init(void)
/* the kernel is still in UP mode, so disabling the IRQs is enough */
local_irq_save(flags);
- atomic_set(&kmemleak_early_log, 0);
- if (atomic_read(&kmemleak_error)) {
+ if (kmemleak_error) {
local_irq_restore(flags);
return;
} else
- atomic_set(&kmemleak_enabled, 1);
+ kmemleak_enabled = 1;
local_irq_restore(flags);
/*
@@ -1844,9 +1844,9 @@ void __init kmemleak_init(void)
log->op_type);
}
- if (atomic_read(&kmemleak_warning)) {
+ if (kmemleak_warning) {
print_log_trace(log);
- atomic_set(&kmemleak_warning, 0);
+ kmemleak_warning = 0;
}
}
}
@@ -1858,9 +1858,9 @@ static int __init kmemleak_late_init(void)
{
struct dentry *dentry;
- atomic_set(&kmemleak_initialized, 1);
+ kmemleak_initialized = 1;
- if (atomic_read(&kmemleak_error)) {
+ if (kmemleak_error) {
/*
* Some error occurred and kmemleak was disabled. There is a
* small chance that kmemleak_disable() was called immediately
--
1.8.0.2
^ permalink raw reply related [flat|nested] 4+ messages in thread