mm: use stack_depot for recording kmemleak's backtrace

Using stack_depot to record kmemleak's backtrace which has been
implemented on slub for reducing redundant information.

[akpm@linux-foundation.org: fix build - remove now-unused __save_stack_trace()]
[zhaoyang.huang@unisoc.com: v3]
Link: https://lkml.kernel.org/r/1667101354-4669-1-git-send-email-zhaoyang.huang@unisoc.com
[akpm@linux-foundation.org: fix v3 layout oddities]
[akpm@linux-foundation.org: coding-style cleanups]
Link: https://lkml.kernel.org/r/1666864224-27541-1-git-send-email-zhaoyang.huang@unisoc.com
Signed-off-by: Zhaoyang Huang <zhaoyang.huang@unisoc.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: ke.wang <ke.wang@unisoc.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zhaoyang Huang <huangzhaoyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index a93c45e..4a23b37 100644 (file)
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -728,6 +728,7 @@ config DEBUG_KMEMLEAK
        select STACKTRACE if STACKTRACE_SUPPORT
        select KALLSYMS
        select CRC32
+       select STACKDEPOT
        help
          Say Y here if you want to enable the memory leak
          detector. The memory allocation/freeing is traced in a way

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index 2673329..dc7db6a 100644 (file)
--- 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 */
@@ -346,18 +346,21 @@ 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);
+                         object->pointer, object->size);
        warn_or_seq_printf(seq, "  comm \"%s\", pid %d, jiffies %lu (age %d.%03ds)\n",
-                  object->comm, object->pid, object->jiffies,
-                  msecs_age / 1000, msecs_age % 1000);
+                          object->comm, object->pid, object->jiffies,
+                          msecs_age / 1000, msecs_age % 1000);
        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];
+       for (i = 0; i < nr_entries; i++) {
+               void *ptr = (void *)entries[i];
                warn_or_seq_printf(seq, "    [<%p>] %pS\n", ptr, ptr);
        }
 }
@@ -370,15 +373,16 @@ static void print_unreferenced(struct seq_file *seq,
 static void dump_object_info(struct kmemleak_object *object)
 {
        pr_notice("Object 0x%08lx (size %zu):\n",
-                 object->pointer, object->size);
+                       object->pointer, object->size);
        pr_notice("  comm \"%s\", pid %d, jiffies %lu\n",
-                 object->comm, object->pid, object->jiffies);
+                       object->comm, object->pid, object->jiffies);
        pr_notice("  min_count = %d\n", object->min_count);
        pr_notice("  count = %d\n", object->count);
        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);
 }
 
 /*
@@ -591,12 +595,18 @@ static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int ali
        return object;
 }
 
-/*
- * Save stack trace to the given array of MAX_TRACE size.
- */
-static int __save_stack_trace(unsigned long *trace)
+static noinline depot_stack_handle_t set_track_prepare(void)
 {
-       return stack_trace_save(trace, MAX_TRACE, 2);
+       depot_stack_handle_t trace_handle;
+       unsigned long entries[MAX_TRACE];
+       unsigned int nr_entries;
+
+       if (!kmemleak_initialized)
+               return 0;
+       nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
+       trace_handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
+
+       return trace_handle;
 }
 
 /*
@@ -653,7 +663,7 @@ static void __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);
 
@@ -692,7 +702,6 @@ static void __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);
@@ -1091,7 +1100,7 @@ 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);
@@ -2084,6 +2093,7 @@ 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);