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slub: use sysfs'es release mechanism for kmem_cache
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debugobjects warning during netfilter exit:

    ------------[ cut here ]------------
    WARNING: CPU: 6 PID: 4178 at lib/debugobjects.c:260 debug_print_object+0x8d/0xb0()
    ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x20
    Modules linked in:
    CPU: 6 PID: 4178 Comm: kworker/u16:2 Tainted: G        W 3.11.0-next-20130906-sasha #3984
    Workqueue: netns cleanup_net
    Call Trace:
      dump_stack+0x52/0x87
      warn_slowpath_common+0x8c/0xc0
      warn_slowpath_fmt+0x46/0x50
      debug_print_object+0x8d/0xb0
      __debug_check_no_obj_freed+0xa5/0x220
      debug_check_no_obj_freed+0x15/0x20
      kmem_cache_free+0x197/0x340
      kmem_cache_destroy+0x86/0xe0
      nf_conntrack_cleanup_net_list+0x131/0x170
      nf_conntrack_pernet_exit+0x5d/0x70
      ops_exit_list+0x5e/0x70
      cleanup_net+0xfb/0x1c0
      process_one_work+0x338/0x550
      worker_thread+0x215/0x350
      kthread+0xe7/0xf0
      ret_from_fork+0x7c/0xb0

Also during dcookie cleanup:

    WARNING: CPU: 12 PID: 9725 at lib/debugobjects.c:260 debug_print_object+0x8c/0xb0()
    ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x20
    Modules linked in:
    CPU: 12 PID: 9725 Comm: trinity-c141 Not tainted 3.15.0-rc2-next-20140423-sasha-00018-gc4ff6c4 torvalds#408
    Call Trace:
      dump_stack (lib/dump_stack.c:52)
      warn_slowpath_common (kernel/panic.c:430)
      warn_slowpath_fmt (kernel/panic.c:445)
      debug_print_object (lib/debugobjects.c:262)
      __debug_check_no_obj_freed (lib/debugobjects.c:697)
      debug_check_no_obj_freed (lib/debugobjects.c:726)
      kmem_cache_free (mm/slub.c:2689 mm/slub.c:2717)
      kmem_cache_destroy (mm/slab_common.c:363)
      dcookie_unregister (fs/dcookies.c:302 fs/dcookies.c:343)
      event_buffer_release (arch/x86/oprofile/../../../drivers/oprofile/event_buffer.c:153)
      __fput (fs/file_table.c:217)
      ____fput (fs/file_table.c:253)
      task_work_run (kernel/task_work.c:125 (discriminator 1))
      do_notify_resume (include/linux/tracehook.h:196 arch/x86/kernel/signal.c:751)
      int_signal (arch/x86/kernel/entry_64.S:807)

Sysfs has a release mechanism.  Use that to release the kmem_cache
structure if CONFIG_SYSFS is enabled.

Only slub is changed - slab currently only supports /proc/slabinfo and
not /sys/kernel/slab/*.  We talked about adding that and someone was
working on it.

[[email protected]: fix CONFIG_SYSFS=n build]
[[email protected]: fix CONFIG_SYSFS=n build even more]
Signed-off-by: Christoph Lameter <[email protected]>
Reported-by: Sasha Levin <[email protected]>
Tested-by: Sasha Levin <[email protected]>
Acked-by: Greg KH <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Pekka Enberg <[email protected]>
Cc: Russell King <[email protected]>
Cc: Bart Van Assche <[email protected]>
Cc: Al Viro <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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@torvalds
Christoph Lameter authored and torvalds committed May 6, 2014
1 parent 6237625 commit 41a2128
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Showing 4 changed files with 29 additions and 24 deletions.
9 changes: 9 additions & 0 deletions include/linux/slub_def.h
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Original file line number Diff line number Diff line change
Expand Up @@ -101,4 +101,13 @@ struct kmem_cache {
struct kmem_cache_node *node[MAX_NUMNODES];
};

#ifdef CONFIG_SYSFS
#define SLAB_SUPPORTS_SYSFS
void sysfs_slab_remove(struct kmem_cache *);
#else
static inline void sysfs_slab_remove(struct kmem_cache *s)
{
}
#endif

#endif /* _LINUX_SLUB_DEF_H */
1 change: 1 addition & 0 deletions mm/slab.h
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Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,7 @@ __kmem_cache_alias(const char *name, size_t size, size_t align,
#define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)

int __kmem_cache_shutdown(struct kmem_cache *);
void slab_kmem_cache_release(struct kmem_cache *);

struct seq_file;
struct file;
Expand Down
13 changes: 11 additions & 2 deletions mm/slab_common.c
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Original file line number Diff line number Diff line change
Expand Up @@ -323,6 +323,12 @@ static int kmem_cache_destroy_memcg_children(struct kmem_cache *s)
}
#endif /* CONFIG_MEMCG_KMEM */

void slab_kmem_cache_release(struct kmem_cache *s)
{
kfree(s->name);
kmem_cache_free(kmem_cache, s);
}

void kmem_cache_destroy(struct kmem_cache *s)
{
get_online_cpus();
Expand Down Expand Up @@ -352,8 +358,11 @@ void kmem_cache_destroy(struct kmem_cache *s)
rcu_barrier();

memcg_free_cache_params(s);
kfree(s->name);
kmem_cache_free(kmem_cache, s);
#ifdef SLAB_SUPPORTS_SYSFS
sysfs_slab_remove(s);
#else
slab_kmem_cache_release(s);
#endif
goto out_put_cpus;

out_unlock:
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30 changes: 8 additions & 22 deletions mm/slub.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -210,14 +210,11 @@ enum track_item { TRACK_ALLOC, TRACK_FREE };
#ifdef CONFIG_SYSFS
static int sysfs_slab_add(struct kmem_cache *);
static int sysfs_slab_alias(struct kmem_cache *, const char *);
static void sysfs_slab_remove(struct kmem_cache *);
static void memcg_propagate_slab_attrs(struct kmem_cache *s);
#else
static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
{ return 0; }
static inline void sysfs_slab_remove(struct kmem_cache *s) { }

static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
#endif

Expand Down Expand Up @@ -3238,24 +3235,7 @@ static inline int kmem_cache_close(struct kmem_cache *s)

int __kmem_cache_shutdown(struct kmem_cache *s)
{
int rc = kmem_cache_close(s);

if (!rc) {
/*
* Since slab_attr_store may take the slab_mutex, we should
* release the lock while removing the sysfs entry in order to
* avoid a deadlock. Because this is pretty much the last
* operation we do and the lock will be released shortly after
* that in slab_common.c, we could just move sysfs_slab_remove
* to a later point in common code. We should do that when we
* have a common sysfs framework for all allocators.
*/
mutex_unlock(&slab_mutex);
sysfs_slab_remove(s);
mutex_lock(&slab_mutex);
}

return rc;
return kmem_cache_close(s);
}

/********************************************************************
Expand Down Expand Up @@ -5122,13 +5102,19 @@ static void memcg_propagate_slab_attrs(struct kmem_cache *s)
#endif
}

static void kmem_cache_release(struct kobject *k)
{
slab_kmem_cache_release(to_slab(k));
}

static const struct sysfs_ops slab_sysfs_ops = {
.show = slab_attr_show,
.store = slab_attr_store,
};

static struct kobj_type slab_ktype = {
.sysfs_ops = &slab_sysfs_ops,
.release = kmem_cache_release,
};

static int uevent_filter(struct kset *kset, struct kobject *kobj)
Expand Down Expand Up @@ -5255,7 +5241,7 @@ static int sysfs_slab_add(struct kmem_cache *s)
goto out;
}

static void sysfs_slab_remove(struct kmem_cache *s)
void sysfs_slab_remove(struct kmem_cache *s)
{
if (slab_state < FULL)
/*
Expand Down

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