The patch titled
Subject: mm: kmemleak: add support for dumping physical and __percpu object info
has been added to the -mm mm-unstable branch. Its filename is
mm-kmemleak-add-support-for-dumping-physical-and-__percpu-object-info.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-kmemleak-add-support-for-dumping-physical-and-__percpu-object-info.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Catalin Marinas <catalin.marinas@xxxxxxx>
Subject: mm: kmemleak: add support for dumping physical and __percpu object info
Date: Thu, 6 Feb 2025 11:45:36 +0000
Patch series "mm: kmemleak: Usability improvements".
Following a recent false positive tracking that led to commit 488b5b9eca68
("mm: kmemleak: fix upper boundary check for physical address objects"), I
needed kmemleak to give me more debug information about the objects it is
tracking. This lead to the first patch of this series. The second patch
changes the kmemleak-test module to show the raw pointers for debugging
purposes.
This patch (of 2):
Currently, echo dump=... > /sys/kernel/debug/kmemleak only looks up the
main virtual address object tree. However, for debugging, it's useful to
dump information about physical address and __percpu objects.
Search all three object trees for the dump= command and also print the
type of the object if not virtual: "(phys)" or "(percpu)". In addition,
allow search by alias (pointer within the object).
Link: https://lkml.kernel.org/r/20250206114537.2597764-1-catalin.marinas@xxxxxxx
Link: https://lkml.kernel.org/r/20250206114537.2597764-2-catalin.marinas@xxxxxxx
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kmemleak.c | 52 ++++++++++++++++++++++++++++++++++++------------
1 file changed, 39 insertions(+), 13 deletions(-)
--- a/mm/kmemleak.c~mm-kmemleak-add-support-for-dumping-physical-and-__percpu-object-info
+++ a/mm/kmemleak.c
@@ -352,6 +352,15 @@ static bool unreferenced_object(struct k
jiffies_last_scan);
}
+static const char *__object_type_str(struct kmemleak_object *object)
+{
+ if (object->flags & OBJECT_PHYS)
+ return " (phys)";
+ if (object->flags & OBJECT_PERCPU)
+ return " (percpu)";
+ return "";
+}
+
/*
* Printing of the unreferenced objects information to the seq file. The
* print_unreferenced function must be called with the object->lock held.
@@ -364,8 +373,9 @@ static void print_unreferenced(struct se
unsigned int nr_entries;
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, "unreferenced object%s 0x%08lx (size %zu):\n",
+ __object_type_str(object),
+ object->pointer, object->size);
warn_or_seq_printf(seq, " comm \"%s\", pid %d, jiffies %lu\n",
object->comm, object->pid, object->jiffies);
hex_dump_object(seq, object);
@@ -384,10 +394,10 @@ static void print_unreferenced(struct se
*/
static void dump_object_info(struct kmemleak_object *object)
{
- pr_notice("Object 0x%08lx (size %zu):\n",
- object->pointer, object->size);
+ pr_notice("Object%s 0x%08lx (size %zu):\n",
+ __object_type_str(object), 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);
@@ -1998,25 +2008,41 @@ static int kmemleak_open(struct inode *i
return seq_open(file, &kmemleak_seq_ops);
}
-static int dump_str_object_info(const char *str)
+static bool __dump_str_object_info(unsigned long addr, unsigned int objflags)
{
unsigned long flags;
struct kmemleak_object *object;
+
+ object = __find_and_get_object(addr, 1, objflags);
+ if (!object)
+ return false;
+
+ raw_spin_lock_irqsave(&object->lock, flags);
+ dump_object_info(object);
+ raw_spin_unlock_irqrestore(&object->lock, flags);
+
+ put_object(object);
+
+ return true;
+}
+
+static int dump_str_object_info(const char *str)
+{
unsigned long addr;
+ bool found = false;
if (kstrtoul(str, 0, &addr))
return -EINVAL;
- object = find_and_get_object(addr, 0);
- if (!object) {
+
+ found |= __dump_str_object_info(addr, 0);
+ found |= __dump_str_object_info(addr, OBJECT_PHYS);
+ found |= __dump_str_object_info(addr, OBJECT_PERCPU);
+
+ if (!found) {
pr_info("Unknown object at 0x%08lx\n", addr);
return -EINVAL;
}
- raw_spin_lock_irqsave(&object->lock, flags);
- dump_object_info(object);
- raw_spin_unlock_irqrestore(&object->lock, flags);
-
- put_object(object);
return 0;
}
_
Patches currently in -mm which might be from catalin.marinas@xxxxxxx are
mm-kmemleak-add-support-for-dumping-physical-and-__percpu-object-info.patch
samples-kmemleak-print-the-raw-pointers-for-debugging-purposes.patch
