From: Vlastimil Babka <vbabka@suse.cz>
To: Alexander Potapenko <glider@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Andrew Morton <akpm@linux-foundation.org>,
Andrey Konovalov <andreyknvl@google.com>,
Andy Lutomirski <luto@kernel.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
Christoph Hellwig <hch@lst.de>, Christoph Lameter <cl@linux.com>,
David Rientjes <rientjes@google.com>,
Dmitry Vyukov <dvyukov@google.com>,
Eric Dumazet <edumazet@google.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Herbert Xu <herbert@gondor.apana.org.au>,
Ilya Leoshkevich <iii@linux.ibm.com>,
Ingo Molnar <mingo@redhat.com>, Jens Axboe <axboe@kernel.dk>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Kees Cook <keescook@chromium.org>, Marco Elver <elver@google.com>,
Matthew Wilcox <willy@infradead.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
Pekka Enberg <penberg@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Petr Mladek <pmladek@suse.com>,
Steven Rostedt <rostedt@goodmis.org>,
Thomas Gleixner <tglx@linutronix.de>,
Vasily Gorbik <gor@linux.ibm.com>,
Vegard Nossum <vegard.nossum@oracle.com>,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 16/43] kmsan: mm: call KMSAN hooks from SLUB code
Date: Fri, 7 Jan 2022 18:22:10 +0100 [thread overview]
Message-ID: <82de6739-a070-695b-bbc8-dfa931aa5e00@suse.cz> (raw)
In-Reply-To: <20211214162050.660953-17-glider@google.com>
On 12/14/21 17:20, Alexander Potapenko wrote:
> In order to report uninitialized memory coming from heap allocations
> KMSAN has to poison them unless they're created with __GFP_ZERO.
>
> It's handy that we need KMSAN hooks in the places where
> init_on_alloc/init_on_free initialization is performed.
>
> Signed-off-by: Alexander Potapenko <glider@google.com>
> ---
> Link: https://linux-review.googlesource.com/id/I6954b386c5c5d7f99f48bb6cbcc74b75136ce86e
> ---
> mm/slab.h | 1 +
> mm/slub.c | 26 +++++++++++++++++++++++---
> 2 files changed, 24 insertions(+), 3 deletions(-)
>
> diff --git a/mm/slab.h b/mm/slab.h
> index 56ad7eea3ddfb..6175a74047b47 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -521,6 +521,7 @@ static inline void slab_post_alloc_hook(struct kmem_cache *s,
> memset(p[i], 0, s->object_size);
> kmemleak_alloc_recursive(p[i], s->object_size, 1,
> s->flags, flags);
> + kmsan_slab_alloc(s, p[i], flags);
> }
>
> memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
> diff --git a/mm/slub.c b/mm/slub.c
> index abe7db581d686..5a63486e52531 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -22,6 +22,7 @@
> #include <linux/proc_fs.h>
> #include <linux/seq_file.h>
> #include <linux/kasan.h>
> +#include <linux/kmsan.h>
> #include <linux/cpu.h>
> #include <linux/cpuset.h>
> #include <linux/mempolicy.h>
> @@ -346,10 +347,13 @@ static inline void *freelist_dereference(const struct kmem_cache *s,
> (unsigned long)ptr_addr);
> }
>
> +/*
> + * See the comment to get_freepointer_safe().
> + */
I did...
> static inline void *get_freepointer(struct kmem_cache *s, void *object)
> {
> object = kasan_reset_tag(object);
> - return freelist_dereference(s, object + s->offset);
> + return kmsan_init(freelist_dereference(s, object + s->offset));
... but I don't see why it applies to get_freepointer() too? What am I missing?
> }
>
> static void prefetch_freepointer(const struct kmem_cache *s, void *object)
> @@ -357,18 +361,28 @@ static void prefetch_freepointer(const struct kmem_cache *s, void *object)
> prefetchw(object + s->offset);
> }
>
> +/*
> + * When running under KMSAN, get_freepointer_safe() may return an uninitialized
> + * pointer value in the case the current thread loses the race for the next
> + * memory chunk in the freelist. In that case this_cpu_cmpxchg_double() in
> + * slab_alloc_node() will fail, so the uninitialized value won't be used, but
> + * KMSAN will still check all arguments of cmpxchg because of imperfect
> + * handling of inline assembly.
> + * To work around this problem, use kmsan_init() to force initialize the
> + * return value of get_freepointer_safe().
> + */
> static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
> {
> unsigned long freepointer_addr;
> void *p;
>
> if (!debug_pagealloc_enabled_static())
> - return get_freepointer(s, object);
> + return kmsan_init(get_freepointer(s, object));
So here kmsan_init() is done twice?
>
> object = kasan_reset_tag(object);
> freepointer_addr = (unsigned long)object + s->offset;
> copy_from_kernel_nofault(&p, (void **)freepointer_addr, sizeof(p));
> - return freelist_ptr(s, p, freepointer_addr);
> + return kmsan_init(freelist_ptr(s, p, freepointer_addr));
> }
>
> static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
next prev parent reply other threads:[~2022-01-07 17:22 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-14 16:20 [PATCH 00/43] Add KernelMemorySanitizer infrastructure Alexander Potapenko
2021-12-14 16:20 ` [PATCH 01/43] arch/x86: add missing include to sparsemem.h Alexander Potapenko
2021-12-14 16:20 ` [PATCH 02/43] stackdepot: reserve 5 extra bits in depot_stack_handle_t Alexander Potapenko
2021-12-14 16:20 ` [PATCH 03/43] kasan: common: adapt to the new prototype of __stack_depot_save() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 04/43] instrumented.h: allow instrumenting both sides of copy_from_user() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 05/43] asm: x86: instrument usercopy in get_user() and __put_user_size() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 06/43] asm-generic: instrument usercopy in cacheflush.h Alexander Potapenko
2021-12-14 16:20 ` [PATCH 07/43] compiler_attributes.h: add __disable_sanitizer_instrumentation Alexander Potapenko
2021-12-15 13:24 ` Mark Rutland
2021-12-15 13:33 ` Marco Elver
2021-12-14 16:20 ` [PATCH 08/43] kmsan: add ReST documentation Alexander Potapenko
2021-12-14 16:20 ` [PATCH 09/43] kmsan: introduce __no_sanitize_memory and __no_kmsan_checks Alexander Potapenko
2021-12-15 13:27 ` Mark Rutland
2021-12-14 16:20 ` [PATCH 10/43] kmsan: pgtable: reduce vmalloc space Alexander Potapenko
2021-12-15 13:36 ` Mark Rutland
2022-03-18 14:14 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 11/43] libnvdimm/pfn_dev: increase MAX_STRUCT_PAGE_SIZE Alexander Potapenko
2021-12-14 16:20 ` [PATCH 12/43] kcsan: clang: retire CONFIG_KCSAN_KCOV_BROKEN Alexander Potapenko
2021-12-15 13:33 ` Mark Rutland
2021-12-15 13:39 ` Marco Elver
2021-12-15 14:43 ` Mark Rutland
2022-03-18 14:34 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 13/43] kmsan: add KMSAN runtime core Alexander Potapenko
2021-12-14 16:34 ` Greg Kroah-Hartman
2021-12-16 10:33 ` Alexander Potapenko
2021-12-17 16:22 ` Greg Kroah-Hartman
2022-03-21 14:12 ` Alexander Potapenko
[not found] ` <CACT4Y+Y_torRwzh0eDMn+pJh=YT26hGrAPA499WqN1dV+4bDHA@mail.gmail.com>
2022-03-21 13:17 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 14/43] MAINTAINERS: add entry for KMSAN Alexander Potapenko
2021-12-14 16:20 ` [PATCH 15/43] kmsan: mm: maintain KMSAN metadata for page operations Alexander Potapenko
2021-12-14 16:20 ` [PATCH 16/43] kmsan: mm: call KMSAN hooks from SLUB code Alexander Potapenko
2022-01-07 17:22 ` Vlastimil Babka [this message]
2022-03-25 13:15 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 17/43] kmsan: handle task creation and exiting Alexander Potapenko
2021-12-14 16:20 ` [PATCH 18/43] kmsan: unpoison @tlb in arch_tlb_gather_mmu() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 19/43] kmsan: init: call KMSAN initialization routines Alexander Potapenko
2021-12-14 16:20 ` [PATCH 20/43] instrumented.h: add KMSAN support Alexander Potapenko
2021-12-14 16:20 ` [PATCH 21/43] kmsan: mark noinstr as __no_sanitize_memory Alexander Potapenko
2021-12-15 13:49 ` Mark Rutland
2021-12-14 16:20 ` [PATCH 22/43] kmsan: initialize the output of READ_ONCE_NOCHECK() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 23/43] kmsan: make READ_ONCE_TASK_STACK() return initialized values Alexander Potapenko
2021-12-14 16:20 ` [PATCH 24/43] kmsan: disable KMSAN instrumentation for certain kernel parts Alexander Potapenko
2021-12-15 13:53 ` Mark Rutland
2021-12-14 16:20 ` [PATCH 25/43] kmsan: skip shadow checks in files doing context switches Alexander Potapenko
2021-12-15 14:13 ` Mark Rutland
2021-12-15 16:28 ` Alexander Potapenko
2021-12-15 17:22 ` Mark Rutland
2021-12-14 16:20 ` [PATCH 26/43] kmsan: virtio: check/unpoison scatterlist in vring_map_one_sg() Alexander Potapenko
2022-01-06 12:46 ` Michael S. Tsirkin
2021-12-14 16:20 ` [PATCH 27/43] x86: kmsan: add iomem support Alexander Potapenko
2021-12-14 16:20 ` [PATCH 28/43] kmsan: dma: unpoison DMA mappings Alexander Potapenko
2021-12-14 16:20 ` [PATCH 29/43] kmsan: handle memory sent to/from USB Alexander Potapenko
2021-12-14 16:20 ` [PATCH 30/43] kmsan: add tests for KMSAN Alexander Potapenko
2021-12-14 16:20 ` [PATCH 31/43] kmsan: disable strscpy() optimization under KMSAN Alexander Potapenko
2021-12-14 16:20 ` [PATCH 32/43] crypto: kmsan: disable accelerated configs " Alexander Potapenko
2021-12-14 16:20 ` [PATCH 33/43] kmsan: disable physical page merging in biovec Alexander Potapenko
2021-12-15 14:17 ` Mark Rutland
2021-12-15 16:30 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 34/43] kmsan: block: skip bio block merging logic for KMSAN Alexander Potapenko
2021-12-14 16:20 ` [PATCH 35/43] x86: kmsan: use __msan_ string functions where possible Alexander Potapenko
2021-12-14 16:20 ` [PATCH 36/43] x86: kmsan: sync metadata pages on page fault Alexander Potapenko
2021-12-14 16:20 ` [PATCH 37/43] x86: kasan: kmsan: support CONFIG_GENERIC_CSUM on x86, enable it for KASAN/KMSAN Alexander Potapenko
2021-12-14 16:20 ` [PATCH 38/43] x86: fs: kmsan: disable CONFIG_DCACHE_WORD_ACCESS Alexander Potapenko
2021-12-14 16:20 ` [PATCH 39/43] x86: kmsan: handle register passing from uninstrumented code Alexander Potapenko
2021-12-17 21:51 ` Thomas Gleixner
2021-12-20 14:35 ` Alexander Potapenko
2021-12-14 16:20 ` [PATCH 40/43] kmsan: kcov: unpoison area->list in kcov_remote_area_put() Alexander Potapenko
2021-12-14 16:20 ` [PATCH 41/43] security: kmsan: fix interoperability with auto-initialization Alexander Potapenko
2021-12-14 16:38 ` Greg Kroah-Hartman
2021-12-14 17:00 ` Alexander Potapenko
2021-12-14 17:33 ` Greg Kroah-Hartman
2021-12-14 16:20 ` [PATCH 42/43] objtool: kmsan: list KMSAN API functions as uaccess-safe Alexander Potapenko
2021-12-14 16:20 ` [PATCH 43/43] x86: kmsan: enable KMSAN builds for x86 Alexander Potapenko
2021-12-14 16:36 ` [PATCH 00/43] Add KernelMemorySanitizer infrastructure Greg Kroah-Hartman
2021-12-16 10:12 ` Alexander Potapenko
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