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Message-Id: <20230804091136.1177-4-thunder.leizhen@huaweicloud.com>
Date: Fri, 4 Aug 2023 17:11:33 +0800
From: thunder.leizhen@...weicloud.com
To: Petr Mladek <pmladek@...e.com>,
Sergey Senozhatsky <senozhatsky@...omium.org>,
Steven Rostedt <rostedt@...dmis.org>,
John Ogness <john.ogness@...utronix.de>,
Christoph Lameter <cl@...ux.com>,
Pekka Enberg <penberg@...nel.org>,
David Rientjes <rientjes@...gle.com>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
Andrew Morton <akpm@...ux-foundation.org>,
Vlastimil Babka <vbabka@...e.cz>,
Roman Gushchin <roman.gushchin@...ux.dev>,
Hyeonggon Yoo <42.hyeyoo@...il.com>, linux-mm@...ck.org,
"Paul E . McKenney" <paulmck@...nel.org>,
Frederic Weisbecker <frederic@...nel.org>,
Neeraj Upadhyay <quic_neeraju@...cinc.com>,
Joel Fernandes <joel@...lfernandes.org>,
Josh Triplett <josh@...htriplett.org>,
Boqun Feng <boqun.feng@...il.com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Lai Jiangshan <jiangshanlai@...il.com>,
Zqiang <qiang.zhang1211@...il.com>, rcu@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Zhen Lei <thunder.leizhen@...wei.com>
Subject: [PATCH v6 3/5] mm: Remove kmem_valid_obj()
From: Zhen Lei <thunder.leizhen@...wei.com>
Function kmem_dump_obj() will splat if passed a pointer to a non-slab
object. So no one will call it directly. It is always necessary to call
kmem_valid_obj() first to determine whether the passed pointer to a
valid slab object. Then merging kmem_valid_obj() into kmem_dump_obj()
will make the code more concise. So convert kmem_dump_obj() to work the
same way as vmalloc_dump_obj(). After this, no one calls kmem_valid_obj()
anymore, and it can be safely removed.
Suggested-by: Matthew Wilcox <willy@...radead.org>
Signed-off-by: Zhen Lei <thunder.leizhen@...wei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@...radead.org>
Acked-by: Vlastimil Babka <vbabka@...e.cz>
---
include/linux/slab.h | 5 +++--
mm/slab_common.c | 41 +++++++++++------------------------------
mm/util.c | 4 +---
3 files changed, 15 insertions(+), 35 deletions(-)
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 848c7c82ad5ad0b..d8ed2e810ec4448 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -244,8 +244,9 @@ DEFINE_FREE(kfree, void *, if (_T) kfree(_T))
size_t ksize(const void *objp);
#ifdef CONFIG_PRINTK
-bool kmem_valid_obj(void *object);
-void kmem_dump_obj(void *object);
+bool kmem_dump_obj(void *object);
+#else
+static inline bool kmem_dump_obj(void *object) { return false; }
#endif
/*
diff --git a/mm/slab_common.c b/mm/slab_common.c
index d1555ea2981ac51..ee6ed6dd7ba9fa5 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -528,26 +528,6 @@ bool slab_is_available(void)
}
#ifdef CONFIG_PRINTK
-/**
- * kmem_valid_obj - does the pointer reference a valid slab object?
- * @object: pointer to query.
- *
- * Return: %true if the pointer is to a not-yet-freed object from
- * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer
- * is to an already-freed object, and %false otherwise.
- */
-bool kmem_valid_obj(void *object)
-{
- struct folio *folio;
-
- /* Some arches consider ZERO_SIZE_PTR to be a valid address. */
- if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))
- return false;
- folio = virt_to_folio(object);
- return folio_test_slab(folio);
-}
-EXPORT_SYMBOL_GPL(kmem_valid_obj);
-
static void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
{
if (__kfence_obj_info(kpp, object, slab))
@@ -566,11 +546,11 @@ static void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *
* and, if available, the slab name, return address, and stack trace from
* the allocation and last free path of that object.
*
- * This function will splat if passed a pointer to a non-slab object.
- * If you are not sure what type of object you have, you should instead
- * use mem_dump_obj().
+ * Return: %true if the pointer is to a not-yet-freed object from
+ * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer
+ * is to an already-freed object, and %false otherwise.
*/
-void kmem_dump_obj(void *object)
+bool kmem_dump_obj(void *object)
{
char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc";
int i;
@@ -578,13 +558,13 @@ void kmem_dump_obj(void *object)
unsigned long ptroffset;
struct kmem_obj_info kp = { };
- if (WARN_ON_ONCE(!virt_addr_valid(object)))
- return;
+ /* Some arches consider ZERO_SIZE_PTR to be a valid address. */
+ if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))
+ return false;
slab = virt_to_slab(object);
- if (WARN_ON_ONCE(!slab)) {
- pr_cont(" non-slab memory.\n");
- return;
- }
+ if (!slab)
+ return false;
+
kmem_obj_info(&kp, object, slab);
if (kp.kp_slab_cache)
pr_cont(" slab%s %s", cp, kp.kp_slab_cache->name);
@@ -621,6 +601,7 @@ void kmem_dump_obj(void *object)
pr_info(" %pS\n", kp.kp_free_stack[i]);
}
+ return true;
}
EXPORT_SYMBOL_GPL(kmem_dump_obj);
#endif
diff --git a/mm/util.c b/mm/util.c
index dd12b9531ac4cad..ddfbb22dc1876d3 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -1063,10 +1063,8 @@ void mem_dump_obj(void *object)
{
const char *type;
- if (kmem_valid_obj(object)) {
- kmem_dump_obj(object);
+ if (kmem_dump_obj(object))
return;
- }
if (vmalloc_dump_obj(object))
return;
--
2.34.1
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