diff options
| -rw-r--r-- | Documentation/kmemleak.txt | 15 | ||||
| -rw-r--r-- | mm/kmemleak.c | 46 |
2 files changed, 46 insertions, 15 deletions
diff --git a/Documentation/kmemleak.txt b/Documentation/kmemleak.txt index b6e39739a36d..6c18be97f3dd 100644 --- a/Documentation/kmemleak.txt +++ b/Documentation/kmemleak.txt @@ -53,7 +53,8 @@ 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 @@ -120,6 +121,18 @@ 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 474379ea3cff..06cd22035a92 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); } |