We can account and sort the output via backtrace under this change
On Tue, Oct 11, 2022 at 9:18 AM zhaoyang.huang
<zhaoyang.huang@xxxxxxxxxx> wrote:
>
> From: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
>
> Using stack_depot to record kmemleak's backtrace which has been implemented
> on slub for reducing redundant information.
>
> Signed-off-by: Zhaoyang Huang <zhaoyang.huang@xxxxxxxxxx>
> ---
> mm/kmemleak.c | 43 +++++++++++++++++++++++++++++++++----------
> 1 file changed, 33 insertions(+), 10 deletions(-)
>
> diff --git a/mm/kmemleak.c b/mm/kmemleak.c
> index 1eddc01..c9cee3a 100644
> --- a/mm/kmemleak.c
> +++ b/mm/kmemleak.c
> @@ -79,6 +79,7 @@
> #include <linux/mutex.h>
> #include <linux/rcupdate.h>
> #include <linux/stacktrace.h>
> +#include <linux/stackdepot.h>
> #include <linux/cache.h>
> #include <linux/percpu.h>
> #include <linux/memblock.h>
> @@ -159,8 +160,7 @@ struct kmemleak_object {
> u32 checksum;
> /* memory ranges to be scanned inside an object (empty for all) */
> struct hlist_head area_list;
> - unsigned long trace[MAX_TRACE];
> - unsigned int trace_len;
> + depot_stack_handle_t trace_handle;
> unsigned long jiffies; /* creation timestamp */
> pid_t pid; /* pid of the current task */
> char comm[TASK_COMM_LEN]; /* executable name */
> @@ -346,8 +346,11 @@ static void print_unreferenced(struct seq_file *seq,
> struct kmemleak_object *object)
> {
> int i;
> + unsigned long *entries;
> + unsigned int nr_entries;
> unsigned int msecs_age = jiffies_to_msecs(jiffies - object->jiffies);
>
> + nr_entries = stack_depot_fetch(object->trace_handle, &entries);
> warn_or_seq_printf(seq, "unreferenced object 0x%08lx (size %zu):\n",
> object->pointer, object->size);
> warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
> @@ -356,10 +359,10 @@ static void print_unreferenced(struct seq_file *seq,
> hex_dump_object(seq, object);
> warn_or_seq_printf(seq, " backtrace:\n");
>
> - for (i = 0; i < object->trace_len; i++) {
> - void *ptr = (void *)object->trace[i];
> - warn_or_seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
> - }
> + for (i = 0; i < nr_entries; i++) {
> + void *ptr = (void *)entries[i];
> + warn_or_seq_printf(seq, " [<%p>] %pS\n", ptr, ptr);
> + }
> }
>
> /*
> @@ -378,7 +381,8 @@ static void dump_object_info(struct kmemleak_object *object)
> pr_notice(" flags = 0x%x\n", object->flags);
> pr_notice(" checksum = %u\n", object->checksum);
> pr_notice(" backtrace:\n");
> - stack_trace_print(object->trace, object->trace_len, 4);
> + if(object->trace_handle)
> + stack_depot_print(object->trace_handle);
> }
>
> /*
> @@ -591,6 +595,25 @@ static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int ali
> return object;
> }
>
> +#ifdef CONFIG_STACKDEPOT
> +static noinline depot_stack_handle_t set_track_prepare(void)
> +{
> + depot_stack_handle_t trace_handle;
> + unsigned long entries[MAX_TRACE];
> + unsigned int nr_entries;
> +
> + nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
> + trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
> +
> + return trace_handle;
> +}
> +#else
> +static inline depot_stack_handle_t set_track_prepare(void)
> +{
> + return 0;
> +}
> +#endif
> +
> /*
> * Save stack trace to the given array of MAX_TRACE size.
> */
> @@ -654,7 +677,7 @@ static struct kmemleak_object *__create_object(unsigned long ptr, size_t size,
> }
>
> /* kernel backtrace */
> - object->trace_len = __save_stack_trace(object->trace);
> + object->trace_handle = set_track_prepare();
>
> raw_spin_lock_irqsave(&kmemleak_lock, flags);
>
> @@ -694,7 +717,6 @@ static struct kmemleak_object *__create_object(unsigned long ptr, size_t size,
> rb_link_node(&object->rb_node, rb_parent, link);
> rb_insert_color(&object->rb_node, is_phys ? &object_phys_tree_root :
> &object_tree_root);
> -
> list_add_tail_rcu(&object->object_list, &object_list);
> out:
> raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
> @@ -1094,7 +1116,7 @@ void __ref kmemleak_update_trace(const void *ptr)
> }
>
> raw_spin_lock_irqsave(&object->lock, flags);
> - object->trace_len = __save_stack_trace(object->trace);
> + object->trace_handle = set_track_prepare();
> raw_spin_unlock_irqrestore(&object->lock, flags);
>
> put_object(object);
> @@ -2064,6 +2086,7 @@ void __init kmemleak_init(void)
> if (kmemleak_error)
> return;
>
> + stack_depot_init();
> jiffies_min_age = msecs_to_jiffies(MSECS_MIN_AGE);
> jiffies_scan_wait = msecs_to_jiffies(SECS_SCAN_WAIT * 1000);
>
> --
> 1.9.1
>
