diff mbox series

[v2,03/21] KASAN: remove code paths guarded by CONFIG_SLAB

Message ID 20231120-slab-remove-slab-v2-3-9c9c70177183@suse.cz (mailing list archive)
State New
Headers show
Series remove the SLAB allocator | expand

Commit Message

Vlastimil Babka Nov. 20, 2023, 6:34 p.m. UTC
With SLAB removed and SLUB the only remaining allocator, we can clean up
some code that was depending on the choice.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
---
 mm/kasan/common.c     | 13 ++-----------
 mm/kasan/kasan.h      |  3 +--
 mm/kasan/quarantine.c |  7 -------
 3 files changed, 3 insertions(+), 20 deletions(-)

Comments

Hyeonggon Yoo Nov. 21, 2023, 8:23 a.m. UTC | #1
On Tue, Nov 21, 2023 at 3:34 AM Vlastimil Babka <vbabka@suse.cz> wrote:
>
> With SLAB removed and SLUB the only remaining allocator, we can clean up
> some code that was depending on the choice.
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Marco Elver <elver@google.com>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---

[...]

> diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
> index ca4529156735..138c57b836f2 100644
> --- a/mm/kasan/quarantine.c
> +++ b/mm/kasan/quarantine.c
> @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
>  {
>         void *object = qlink_to_object(qlink, cache);
>         struct kasan_free_meta *meta = kasan_get_free_meta(cache, object);
> -       unsigned long flags;
> -
> -       if (IS_ENABLED(CONFIG_SLAB))
> -               local_irq_save(flags);
>
>         /*
>          * If init_on_free is enabled and KASAN's free metadata is stored in
> @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
>         *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE;
>
>         ___cache_free(cache, object, _THIS_IP_);
> -
> -       if (IS_ENABLED(CONFIG_SLAB))
> -               local_irq_restore(flags);
>  }

FYI there's a slight conflict (easy to resolve, though) when I tried
to merge this on top of linux-next,
due to a recent change in KASAN:

https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=0e8b630f3053f0ff84b7c3ab8ff98a7393863824

Thanks,
Hyeonggon
Andrey Konovalov Nov. 21, 2023, 4:47 p.m. UTC | #2
On Mon, Nov 20, 2023 at 7:34 PM Vlastimil Babka <vbabka@suse.cz> wrote:
>
> With SLAB removed and SLUB the only remaining allocator, we can clean up
> some code that was depending on the choice.
>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Marco Elver <elver@google.com>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---
>  mm/kasan/common.c     | 13 ++-----------
>  mm/kasan/kasan.h      |  3 +--
>  mm/kasan/quarantine.c |  7 -------
>  3 files changed, 3 insertions(+), 20 deletions(-)
>
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index 256930da578a..5d95219e69d7 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -153,10 +153,6 @@ void __kasan_poison_object_data(struct kmem_cache *cache, void *object)
>   * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be
>   *    accessed after being freed. We preassign tags for objects in these
>   *    caches as well.
> - * 3. For SLAB allocator we can't preassign tags randomly since the freelist
> - *    is stored as an array of indexes instead of a linked list. Assign tags
> - *    based on objects indexes, so that objects that are next to each other
> - *    get different tags.
>   */
>  static inline u8 assign_tag(struct kmem_cache *cache,
>                                         const void *object, bool init)
> @@ -171,17 +167,12 @@ static inline u8 assign_tag(struct kmem_cache *cache,
>         if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU))
>                 return init ? KASAN_TAG_KERNEL : kasan_random_tag();
>
> -       /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
> -#ifdef CONFIG_SLAB
> -       /* For SLAB assign tags based on the object index in the freelist. */
> -       return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object);
> -#else
>         /*
> -        * For SLUB assign a random tag during slab creation, otherwise reuse
> +        * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU,
> +        * assign a random tag during slab creation, otherwise reuse
>          * the already assigned tag.
>          */
>         return init ? kasan_random_tag() : get_tag(object);
> -#endif
>  }
>
>  void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache,
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 8b06bab5c406..eef50233640a 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -373,8 +373,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags);
>  void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags);
>  void kasan_save_free_info(struct kmem_cache *cache, void *object);
>
> -#if defined(CONFIG_KASAN_GENERIC) && \
> -       (defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
> +#ifdef CONFIG_KASAN_GENERIC
>  bool kasan_quarantine_put(struct kmem_cache *cache, void *object);
>  void kasan_quarantine_reduce(void);
>  void kasan_quarantine_remove_cache(struct kmem_cache *cache);
> diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
> index ca4529156735..138c57b836f2 100644
> --- a/mm/kasan/quarantine.c
> +++ b/mm/kasan/quarantine.c
> @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
>  {
>         void *object = qlink_to_object(qlink, cache);
>         struct kasan_free_meta *meta = kasan_get_free_meta(cache, object);
> -       unsigned long flags;
> -
> -       if (IS_ENABLED(CONFIG_SLAB))
> -               local_irq_save(flags);
>
>         /*
>          * If init_on_free is enabled and KASAN's free metadata is stored in
> @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
>         *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE;
>
>         ___cache_free(cache, object, _THIS_IP_);
> -
> -       if (IS_ENABLED(CONFIG_SLAB))
> -               local_irq_restore(flags);
>  }
>
>  static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache)
>
> --
> 2.42.1
>

Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>

Very nice to see SLAB-induced complexity being gone :)

Thank you!
Hyeonggon Yoo Dec. 5, 2023, 4:26 a.m. UTC | #3
On Mon, Nov 20, 2023 at 07:34:14PM +0100, Vlastimil Babka wrote:
> With SLAB removed and SLUB the only remaining allocator, we can clean up
> some code that was depending on the choice.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Marco Elver <elver@google.com>
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---
>  mm/kasan/common.c     | 13 ++-----------
>  mm/kasan/kasan.h      |  3 +--
>  mm/kasan/quarantine.c |  7 -------
>  3 files changed, 3 insertions(+), 20 deletions(-)
> 
> diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> index 256930da578a..5d95219e69d7 100644
> --- a/mm/kasan/common.c
> +++ b/mm/kasan/common.c
> @@ -153,10 +153,6 @@ void __kasan_poison_object_data(struct kmem_cache *cache, void *object)
>   * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be
>   *    accessed after being freed. We preassign tags for objects in these
>   *    caches as well.
> - * 3. For SLAB allocator we can't preassign tags randomly since the freelist
> - *    is stored as an array of indexes instead of a linked list. Assign tags
> - *    based on objects indexes, so that objects that are next to each other
> - *    get different tags.
>   */
>  static inline u8 assign_tag(struct kmem_cache *cache,
>  					const void *object, bool init)
> @@ -171,17 +167,12 @@ static inline u8 assign_tag(struct kmem_cache *cache,
>  	if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU))
>  		return init ? KASAN_TAG_KERNEL : kasan_random_tag();
>  
> -	/* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
> -#ifdef CONFIG_SLAB
> -	/* For SLAB assign tags based on the object index in the freelist. */
> -	return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object);
> -#else
>  	/*
> -	 * For SLUB assign a random tag during slab creation, otherwise reuse
> +	 * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU,
> +	 * assign a random tag during slab creation, otherwise reuse
>  	 * the already assigned tag.
>  	 */
>  	return init ? kasan_random_tag() : get_tag(object);
> -#endif
>  }
>  
>  void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache,
> diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> index 8b06bab5c406..eef50233640a 100644
> --- a/mm/kasan/kasan.h
> +++ b/mm/kasan/kasan.h
> @@ -373,8 +373,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags);
>  void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags);
>  void kasan_save_free_info(struct kmem_cache *cache, void *object);
>  
> -#if defined(CONFIG_KASAN_GENERIC) && \
> -	(defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
> +#ifdef CONFIG_KASAN_GENERIC
>  bool kasan_quarantine_put(struct kmem_cache *cache, void *object);
>  void kasan_quarantine_reduce(void);
>  void kasan_quarantine_remove_cache(struct kmem_cache *cache);
> diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
> index ca4529156735..138c57b836f2 100644
> --- a/mm/kasan/quarantine.c
> +++ b/mm/kasan/quarantine.c
> @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
>  {
>  	void *object = qlink_to_object(qlink, cache);
>  	struct kasan_free_meta *meta = kasan_get_free_meta(cache, object);
> -	unsigned long flags;
> -
> -	if (IS_ENABLED(CONFIG_SLAB))
> -		local_irq_save(flags);
>  
>  	/*
>  	 * If init_on_free is enabled and KASAN's free metadata is stored in
> @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
>  	*(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE;
>  
>  	___cache_free(cache, object, _THIS_IP_);
> -
> -	if (IS_ENABLED(CONFIG_SLAB))
> -		local_irq_restore(flags);
>  }
>  
>  static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache)

Looks good to me,
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

> 
> -- 
> 2.42.1
> 
>
Hyeonggon Yoo Dec. 5, 2023, 4:48 a.m. UTC | #4
On Tue, Dec 5, 2023 at 1:27 PM Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote:
>
> On Mon, Nov 20, 2023 at 07:34:14PM +0100, Vlastimil Babka wrote:
> > With SLAB removed and SLUB the only remaining allocator, we can clean up
> > some code that was depending on the choice.
> >
> > Reviewed-by: Kees Cook <keescook@chromium.org>
> > Reviewed-by: Marco Elver <elver@google.com>
> > Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> > ---
> >  mm/kasan/common.c     | 13 ++-----------
> >  mm/kasan/kasan.h      |  3 +--
> >  mm/kasan/quarantine.c |  7 -------
> >  3 files changed, 3 insertions(+), 20 deletions(-)
> >
> > diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> > index 256930da578a..5d95219e69d7 100644
> > --- a/mm/kasan/common.c
> > +++ b/mm/kasan/common.c
> > @@ -153,10 +153,6 @@ void __kasan_poison_object_data(struct kmem_cache *cache, void *object)
> >   * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be
> >   *    accessed after being freed. We preassign tags for objects in these
> >   *    caches as well.
> > - * 3. For SLAB allocator we can't preassign tags randomly since the freelist
> > - *    is stored as an array of indexes instead of a linked list. Assign tags
> > - *    based on objects indexes, so that objects that are next to each other
> > - *    get different tags.
> >   */
> >  static inline u8 assign_tag(struct kmem_cache *cache,
> >                                       const void *object, bool init)
> > @@ -171,17 +167,12 @@ static inline u8 assign_tag(struct kmem_cache *cache,
> >       if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU))
> >               return init ? KASAN_TAG_KERNEL : kasan_random_tag();
> >
> > -     /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
> > -#ifdef CONFIG_SLAB
> > -     /* For SLAB assign tags based on the object index in the freelist. */
> > -     return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object);
> > -#else
> >       /*
> > -      * For SLUB assign a random tag during slab creation, otherwise reuse
> > +      * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU,
> > +      * assign a random tag during slab creation, otherwise reuse
> >        * the already assigned tag.
> >        */
> >       return init ? kasan_random_tag() : get_tag(object);
> > -#endif
> >  }
> >
> >  void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache,
> > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
> > index 8b06bab5c406..eef50233640a 100644
> > --- a/mm/kasan/kasan.h
> > +++ b/mm/kasan/kasan.h
> > @@ -373,8 +373,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags);
> >  void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags);
> >  void kasan_save_free_info(struct kmem_cache *cache, void *object);
> >
> > -#if defined(CONFIG_KASAN_GENERIC) && \
> > -     (defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
> > +#ifdef CONFIG_KASAN_GENERIC
> >  bool kasan_quarantine_put(struct kmem_cache *cache, void *object);
> >  void kasan_quarantine_reduce(void);
> >  void kasan_quarantine_remove_cache(struct kmem_cache *cache);
> > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
> > index ca4529156735..138c57b836f2 100644
> > --- a/mm/kasan/quarantine.c
> > +++ b/mm/kasan/quarantine.c
> > @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
> >  {
> >       void *object = qlink_to_object(qlink, cache);
> >       struct kasan_free_meta *meta = kasan_get_free_meta(cache, object);
> > -     unsigned long flags;
> > -
> > -     if (IS_ENABLED(CONFIG_SLAB))
> > -             local_irq_save(flags);
> >
> >       /*
> >        * If init_on_free is enabled and KASAN's free metadata is stored in
> > @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
> >       *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE;
> >
> >       ___cache_free(cache, object, _THIS_IP_);
> > -
> > -     if (IS_ENABLED(CONFIG_SLAB))
> > -             local_irq_restore(flags);
> >  }
> >
> >  static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache)
>
> Looks good to me,
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

nit: Some KASAN tests depends on SLUB, but as now it's the only allocator
      KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); in
      mm/kasan/kasan_test.c can be removed

>
> >
> > --
> > 2.42.1
> >
> >
Vlastimil Babka Dec. 5, 2023, 10:16 a.m. UTC | #5
On 12/5/23 05:48, Hyeonggon Yoo wrote:
> On Tue, Dec 5, 2023 at 1:27 PM Hyeonggon Yoo <42.hyeyoo@gmail.com> wrote:
>>
>> On Mon, Nov 20, 2023 at 07:34:14PM +0100, Vlastimil Babka wrote:
>> > With SLAB removed and SLUB the only remaining allocator, we can clean up
>> > some code that was depending on the choice.
>> >
>> > Reviewed-by: Kees Cook <keescook@chromium.org>
>> > Reviewed-by: Marco Elver <elver@google.com>
>> > Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
>> > ---
>> >  mm/kasan/common.c     | 13 ++-----------
>> >  mm/kasan/kasan.h      |  3 +--
>> >  mm/kasan/quarantine.c |  7 -------
>> >  3 files changed, 3 insertions(+), 20 deletions(-)
>> >
>> > diff --git a/mm/kasan/common.c b/mm/kasan/common.c
>> > index 256930da578a..5d95219e69d7 100644
>> > --- a/mm/kasan/common.c
>> > +++ b/mm/kasan/common.c
>> > @@ -153,10 +153,6 @@ void __kasan_poison_object_data(struct kmem_cache *cache, void *object)
>> >   * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be
>> >   *    accessed after being freed. We preassign tags for objects in these
>> >   *    caches as well.
>> > - * 3. For SLAB allocator we can't preassign tags randomly since the freelist
>> > - *    is stored as an array of indexes instead of a linked list. Assign tags
>> > - *    based on objects indexes, so that objects that are next to each other
>> > - *    get different tags.
>> >   */
>> >  static inline u8 assign_tag(struct kmem_cache *cache,
>> >                                       const void *object, bool init)
>> > @@ -171,17 +167,12 @@ static inline u8 assign_tag(struct kmem_cache *cache,
>> >       if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU))
>> >               return init ? KASAN_TAG_KERNEL : kasan_random_tag();
>> >
>> > -     /* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
>> > -#ifdef CONFIG_SLAB
>> > -     /* For SLAB assign tags based on the object index in the freelist. */
>> > -     return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object);
>> > -#else
>> >       /*
>> > -      * For SLUB assign a random tag during slab creation, otherwise reuse
>> > +      * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU,
>> > +      * assign a random tag during slab creation, otherwise reuse
>> >        * the already assigned tag.
>> >        */
>> >       return init ? kasan_random_tag() : get_tag(object);
>> > -#endif
>> >  }
>> >
>> >  void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache,
>> > diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
>> > index 8b06bab5c406..eef50233640a 100644
>> > --- a/mm/kasan/kasan.h
>> > +++ b/mm/kasan/kasan.h
>> > @@ -373,8 +373,7 @@ void kasan_set_track(struct kasan_track *track, gfp_t flags);
>> >  void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags);
>> >  void kasan_save_free_info(struct kmem_cache *cache, void *object);
>> >
>> > -#if defined(CONFIG_KASAN_GENERIC) && \
>> > -     (defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
>> > +#ifdef CONFIG_KASAN_GENERIC
>> >  bool kasan_quarantine_put(struct kmem_cache *cache, void *object);
>> >  void kasan_quarantine_reduce(void);
>> >  void kasan_quarantine_remove_cache(struct kmem_cache *cache);
>> > diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
>> > index ca4529156735..138c57b836f2 100644
>> > --- a/mm/kasan/quarantine.c
>> > +++ b/mm/kasan/quarantine.c
>> > @@ -144,10 +144,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
>> >  {
>> >       void *object = qlink_to_object(qlink, cache);
>> >       struct kasan_free_meta *meta = kasan_get_free_meta(cache, object);
>> > -     unsigned long flags;
>> > -
>> > -     if (IS_ENABLED(CONFIG_SLAB))
>> > -             local_irq_save(flags);
>> >
>> >       /*
>> >        * If init_on_free is enabled and KASAN's free metadata is stored in
>> > @@ -166,9 +162,6 @@ static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
>> >       *(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE;
>> >
>> >       ___cache_free(cache, object, _THIS_IP_);
>> > -
>> > -     if (IS_ENABLED(CONFIG_SLAB))
>> > -             local_irq_restore(flags);
>> >  }
>> >
>> >  static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache)
>>
>> Looks good to me,
>> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>

Thanks!

> nit: Some KASAN tests depends on SLUB, but as now it's the only allocator
>       KASAN_TEST_NEEDS_CONFIG_ON(test, CONFIG_SLUB); in
>       mm/kasan/kasan_test.c can be removed

Hmm I see, but will rather also leave it for later cleanup at this point,
thanks!

>>
>> >
>> > --
>> > 2.42.1
>> >
>> >
diff mbox series

Patch

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 256930da578a..5d95219e69d7 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -153,10 +153,6 @@  void __kasan_poison_object_data(struct kmem_cache *cache, void *object)
  * 2. A cache might be SLAB_TYPESAFE_BY_RCU, which means objects can be
  *    accessed after being freed. We preassign tags for objects in these
  *    caches as well.
- * 3. For SLAB allocator we can't preassign tags randomly since the freelist
- *    is stored as an array of indexes instead of a linked list. Assign tags
- *    based on objects indexes, so that objects that are next to each other
- *    get different tags.
  */
 static inline u8 assign_tag(struct kmem_cache *cache,
 					const void *object, bool init)
@@ -171,17 +167,12 @@  static inline u8 assign_tag(struct kmem_cache *cache,
 	if (!cache->ctor && !(cache->flags & SLAB_TYPESAFE_BY_RCU))
 		return init ? KASAN_TAG_KERNEL : kasan_random_tag();
 
-	/* For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU: */
-#ifdef CONFIG_SLAB
-	/* For SLAB assign tags based on the object index in the freelist. */
-	return (u8)obj_to_index(cache, virt_to_slab(object), (void *)object);
-#else
 	/*
-	 * For SLUB assign a random tag during slab creation, otherwise reuse
+	 * For caches that either have a constructor or SLAB_TYPESAFE_BY_RCU,
+	 * assign a random tag during slab creation, otherwise reuse
 	 * the already assigned tag.
 	 */
 	return init ? kasan_random_tag() : get_tag(object);
-#endif
 }
 
 void * __must_check __kasan_init_slab_obj(struct kmem_cache *cache,
diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h
index 8b06bab5c406..eef50233640a 100644
--- a/mm/kasan/kasan.h
+++ b/mm/kasan/kasan.h
@@ -373,8 +373,7 @@  void kasan_set_track(struct kasan_track *track, gfp_t flags);
 void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags);
 void kasan_save_free_info(struct kmem_cache *cache, void *object);
 
-#if defined(CONFIG_KASAN_GENERIC) && \
-	(defined(CONFIG_SLAB) || defined(CONFIG_SLUB))
+#ifdef CONFIG_KASAN_GENERIC
 bool kasan_quarantine_put(struct kmem_cache *cache, void *object);
 void kasan_quarantine_reduce(void);
 void kasan_quarantine_remove_cache(struct kmem_cache *cache);
diff --git a/mm/kasan/quarantine.c b/mm/kasan/quarantine.c
index ca4529156735..138c57b836f2 100644
--- a/mm/kasan/quarantine.c
+++ b/mm/kasan/quarantine.c
@@ -144,10 +144,6 @@  static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
 {
 	void *object = qlink_to_object(qlink, cache);
 	struct kasan_free_meta *meta = kasan_get_free_meta(cache, object);
-	unsigned long flags;
-
-	if (IS_ENABLED(CONFIG_SLAB))
-		local_irq_save(flags);
 
 	/*
 	 * If init_on_free is enabled and KASAN's free metadata is stored in
@@ -166,9 +162,6 @@  static void qlink_free(struct qlist_node *qlink, struct kmem_cache *cache)
 	*(u8 *)kasan_mem_to_shadow(object) = KASAN_SLAB_FREE;
 
 	___cache_free(cache, object, _THIS_IP_);
-
-	if (IS_ENABLED(CONFIG_SLAB))
-		local_irq_restore(flags);
 }
 
 static void qlist_free_all(struct qlist_head *q, struct kmem_cache *cache)