[PATCH tip/core/rcu 0/2] mm_dump_obj() updates for v5.13

[PATCH tip/core/rcu 0/2] mm_dump_obj() updates for v5.13

[Paul E. McKenney]

Hello!

This series contains the following:

1.	Don't build mm_dump_obj() on CONFIG_PRINTK=n kernels.

2.	Add crude tests for mem_dump_obj().

						Thanx, Paul

------------------------------------------------------------------------

 include/linux/mm.h      |    4 ++++
 include/linux/slab.h    |    2 ++
 include/linux/vmalloc.h |    2 +-
 kernel/rcu/rcutorture.c |   39 +++++++++++++++++++++++++++++++++++++++
 mm/slab.c               |    2 ++
 mm/slab.h               |    2 ++
 mm/slab_common.c        |    4 ++++
 mm/slob.c               |    2 ++
 mm/slub.c               |    2 ++
 mm/util.c               |    3 +++
 mm/vmalloc.c            |    2 ++
 11 files changed, 63 insertions(+), 1 deletion(-)

[PATCH tip/core/rcu 1/2] mm: Don't build mm_dump_obj() on CONFIG_PRINTK=n kernels

[paulmck]

From: "Paul E. McKenney" <paulmck@kernel.org>

The mem_dump_obj() functionality adds a few hundred bytes, which is a
small price to pay.  Except on kernels built with CONFIG_PRINTK=n, in
which mem_dump_obj() messages will be suppressed.  This commit therefore
makes mem_dump_obj() be a static inline empty function on kernels built
with CONFIG_PRINTK=n and excludes all of its support functions as well.
This avoids kernel bloat on systems that cannot use mem_dump_obj().

Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <linux-mm@kvack.org>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 include/linux/mm.h      | 4 ++++
 include/linux/slab.h    | 2 ++
 include/linux/vmalloc.h | 2 +-
 mm/slab.c               | 2 ++
 mm/slab.h               | 2 ++
 mm/slab_common.c        | 2 ++
 mm/slob.c               | 2 ++
 mm/slub.c               | 2 ++
 mm/util.c               | 2 ++
 mm/vmalloc.c            | 2 ++
 10 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 77e64e3..89fca44 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3135,7 +3135,11 @@ unsigned long wp_shared_mapping_range(struct address_space *mapping,
 
 extern int sysctl_nr_trim_pages;
 
+#ifdef CONFIG_PRINTK
 void mem_dump_obj(void *object);
+#else
+static inline void mem_dump_obj(void *object) {}
+#endif
 
 #endif /* __KERNEL__ */
 #endif /* _LINUX_MM_H */
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 7ae6040..0c97d78 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -186,8 +186,10 @@ void kfree(const void *);
 void kfree_sensitive(const void *);
 size_t __ksize(const void *);
 size_t ksize(const void *);
+#ifdef CONFIG_PRINTK
 bool kmem_valid_obj(void *object);
 void kmem_dump_obj(void *object);
+#endif
 
 #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index df92211..3de7be6 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -241,7 +241,7 @@ pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
 int register_vmap_purge_notifier(struct notifier_block *nb);
 int unregister_vmap_purge_notifier(struct notifier_block *nb);
 
-#ifdef CONFIG_MMU
+#if defined(CONFIG_MMU) && defined(CONFIG_PRINTK)
 bool vmalloc_dump_obj(void *object);
 #else
 static inline bool vmalloc_dump_obj(void *object) { return false; }
diff --git a/mm/slab.c b/mm/slab.c
index 51fd424..2e64efe 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -3651,6 +3651,7 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
 EXPORT_SYMBOL(__kmalloc_node_track_caller);
 #endif /* CONFIG_NUMA */
 
+#ifdef CONFIG_PRINTK
 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 {
 	struct kmem_cache *cachep;
@@ -3670,6 +3671,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 	if (DEBUG && cachep->flags & SLAB_STORE_USER)
 		kpp->kp_ret = *dbg_userword(cachep, objp);
 }
+#endif
 
 /**
  * __do_kmalloc - allocate memory
diff --git a/mm/slab.h b/mm/slab.h
index 076582f..120b1d0 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -619,6 +619,7 @@ static inline bool slab_want_init_on_free(struct kmem_cache *c)
 	return false;
 }
 
+#ifdef CONFIG_PRINTK
 #define KS_ADDRS_COUNT 16
 struct kmem_obj_info {
 	void *kp_ptr;
@@ -630,5 +631,6 @@ struct kmem_obj_info {
 	void *kp_stack[KS_ADDRS_COUNT];
 };
 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page);
+#endif
 
 #endif /* MM_SLAB_H */
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 88e8339..cec9536 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -526,6 +526,7 @@ bool slab_is_available(void)
 	return slab_state >= UP;
 }
 
+#ifdef CONFIG_PRINTK
 /**
  * kmem_valid_obj - does the pointer reference a valid slab object?
  * @object: pointer to query.
@@ -600,6 +601,7 @@ void kmem_dump_obj(void *object)
 		pr_info("    %pS\n", kp.kp_stack[i]);
 	}
 }
+#endif
 
 #ifndef CONFIG_SLOB
 /* Create a cache during boot when no slab services are available yet */
diff --git a/mm/slob.c b/mm/slob.c
index 0578429..74d3f6e 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -461,11 +461,13 @@ static void slob_free(void *block, int size)
 	spin_unlock_irqrestore(&slob_lock, flags);
 }
 
+#ifdef CONFIG_PRINTK
 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 {
 	kpp->kp_ptr = object;
 	kpp->kp_page = page;
 }
+#endif
 
 /*
  * End of slob allocator proper. Begin kmem_cache_alloc and kmalloc frontend.
diff --git a/mm/slub.c b/mm/slub.c
index e26c274..077a019 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -3963,6 +3963,7 @@ int __kmem_cache_shutdown(struct kmem_cache *s)
 	return 0;
 }
 
+#ifdef CONFIG_PRINTK
 void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 {
 	void *base;
@@ -4002,6 +4003,7 @@ void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page)
 #endif
 #endif
 }
+#endif
 
 /********************************************************************
  *		Kmalloc subsystem
diff --git a/mm/util.c b/mm/util.c
index 5487022..2d497fe 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -983,6 +983,7 @@ int __weak memcmp_pages(struct page *page1, struct page *page2)
 	return ret;
 }
 
+#ifdef CONFIG_PRINTK
 /**
  * mem_dump_obj - Print available provenance information
  * @object: object for which to find provenance information.
@@ -1013,3 +1014,4 @@ void mem_dump_obj(void *object)
 	}
 	pr_cont(" non-slab/vmalloc memory.\n");
 }
+#endif
diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 4f5f8c9..d5f2a84 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -3450,6 +3450,7 @@ void pcpu_free_vm_areas(struct vm_struct **vms, int nr_vms)
 }
 #endif	/* CONFIG_SMP */
 
+#ifdef CONFIG_PRINTK
 bool vmalloc_dump_obj(void *object)
 {
 	struct vm_struct *vm;
@@ -3462,6 +3463,7 @@ bool vmalloc_dump_obj(void *object)
 		vm->nr_pages, (unsigned long)vm->addr, vm->caller);
 	return true;
 }
+#endif
 
 #ifdef CONFIG_PROC_FS
 static void *s_start(struct seq_file *m, loff_t *pos)
-- 
2.9.5

[PATCH tip/core/rcu 2/2] rcutorture: Add crude tests for mem_dump_obj()

[paulmck]

From: "Paul E. McKenney" <paulmck@kernel.org>

This commit adds a few crude tests for mem_dump_obj() to rcutorture
runs.  Just to prevent bitrot, you understand!

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
 kernel/rcu/rcutorture.c | 39 +++++++++++++++++++++++++++++++++++++++
 mm/slab_common.c        |  2 ++
 mm/util.c               |  1 +
 3 files changed, 42 insertions(+)

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 99657ff..8e93f2e 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -1861,6 +1861,45 @@ rcu_torture_stats(void *arg)
 		torture_shutdown_absorb("rcu_torture_stats");
 	} while (!torture_must_stop());
 	torture_kthread_stopping("rcu_torture_stats");
+
+	{
+		struct rcu_head *rhp;
+		struct kmem_cache *kcp;
+		static int z;
+
+		kcp = kmem_cache_create("rcuscale", 136, 8, SLAB_STORE_USER, NULL);
+		rhp = kmem_cache_alloc(kcp, GFP_KERNEL);
+		pr_alert("mem_dump_obj() slab test: rcu_torture_stats = %px, &rhp = %px, rhp = %px, &z = %px\n", stats_task, &rhp, rhp, &z);
+		pr_alert("mem_dump_obj(ZERO_SIZE_PTR):");
+		mem_dump_obj(ZERO_SIZE_PTR);
+		pr_alert("mem_dump_obj(NULL):");
+		mem_dump_obj(NULL);
+		pr_alert("mem_dump_obj(%px):", &rhp);
+		mem_dump_obj(&rhp);
+		pr_alert("mem_dump_obj(%px):", rhp);
+		mem_dump_obj(rhp);
+		pr_alert("mem_dump_obj(%px):", &rhp->func);
+		mem_dump_obj(&rhp->func);
+		pr_alert("mem_dump_obj(%px):", &z);
+		mem_dump_obj(&z);
+		kmem_cache_free(kcp, rhp);
+		kmem_cache_destroy(kcp);
+		rhp = kmalloc(sizeof(*rhp), GFP_KERNEL);
+		pr_alert("mem_dump_obj() kmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
+		pr_alert("mem_dump_obj(kmalloc %px):", rhp);
+		mem_dump_obj(rhp);
+		pr_alert("mem_dump_obj(kmalloc %px):", &rhp->func);
+		mem_dump_obj(&rhp->func);
+		kfree(rhp);
+		rhp = vmalloc(4096);
+		pr_alert("mem_dump_obj() vmalloc test: rcu_torture_stats = %px, &rhp = %px, rhp = %px\n", stats_task, &rhp, rhp);
+		pr_alert("mem_dump_obj(vmalloc %px):", rhp);
+		mem_dump_obj(rhp);
+		pr_alert("mem_dump_obj(vmalloc %px):", &rhp->func);
+		mem_dump_obj(&rhp->func);
+		vfree(rhp);
+	}
+
 	return 0;
 }
 
diff --git a/mm/slab_common.c b/mm/slab_common.c
index cec9536..4c6107e 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -545,6 +545,7 @@ bool kmem_valid_obj(void *object)
 	page = virt_to_head_page(object);
 	return PageSlab(page);
 }
+EXPORT_SYMBOL_GPL(kmem_valid_obj);
 
 /**
  * kmem_dump_obj - Print available slab provenance information
@@ -601,6 +602,7 @@ void kmem_dump_obj(void *object)
 		pr_info("    %pS\n", kp.kp_stack[i]);
 	}
 }
+EXPORT_SYMBOL_GPL(kmem_dump_obj);
 #endif
 
 #ifndef CONFIG_SLOB
diff --git a/mm/util.c b/mm/util.c
index 2d497fe..c37e24d 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -1014,4 +1014,5 @@ void mem_dump_obj(void *object)
 	}
 	pr_cont(" non-slab/vmalloc memory.\n");
 }
+EXPORT_SYMBOL_GPL(mem_dump_obj);
 #endif
-- 
2.9.5