From: Robin Murphy <robin.murphy@arm.com>
To: glider@google.com, Theodore Ts'o <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Vegard Nossum <vegard.nossum@oracle.com>,
Dmitry Vyukov <dvyukov@google.com>,
linux-mm@kvack.org
Cc: viro@zeniv.linux.org.uk, akpm@linux-foundation.org,
andreyknvl@google.com, aryabinin@virtuozzo.com, luto@kernel.org,
ard.biesheuvel@linaro.org, arnd@arndb.de, hch@infradead.org,
hch@lst.de, darrick.wong@oracle.com, davem@davemloft.net,
dmitry.torokhov@gmail.com, ebiggers@google.com,
edumazet@google.com, ericvh@gmail.com,
gregkh@linuxfoundation.org, harry.wentland@amd.com,
herbert@gondor.apana.org.au, iii@linux.ibm.com, mingo@elte.hu,
jasowang@redhat.com, axboe@kernel.dk, m.szyprowski@samsung.com,
elver@google.com, mark.rutland@arm.com,
martin.petersen@oracle.com, schwidefsky@de.ibm.com,
willy@infradead.org, mst@redhat.com, monstr@monstr.eu,
pmladek@suse.com, cai@lca.pw, rdunlap@infradead.org,
sergey.senozhatsky@gmail.com, rostedt@goodmis.org,
tiwai@suse.com, tglx@linutronix.de, gor@linux.ibm.com,
wsa@the-dreams.de
Subject: Re: [PATCH RFC v3 35/36] kmsan: ext4: skip block merging logic in ext4_mpage_readpages for KMSAN
Date: Mon, 25 Nov 2019 16:05:36 +0000 [thread overview]
Message-ID: <3265ac30-4df5-70a9-5634-ea00253d0946@arm.com> (raw)
In-Reply-To: <20191122112621.204798-36-glider@google.com>
On 22/11/2019 11:26 am, glider@google.com wrote:
> KMSAN doesn't allow treating adjacent memory pages as such, if they were
> allocated by different alloc_pages() calls.
> ext4_mpage_readpages() however does so: adjacent pages end up being passed
> together to dma_direct_map_sg().
Urgh, there are definitely more places where physically-contiguous pages
are coalesced into single scatterlist entries - see
sg_alloc_table_from_pages() for instance. I wouldn't be surprised if
there are further open-coded versions hiding out in various other
drivers/subsystems too. Unless I've misunderstood, this seems like quite
an invasive limitation :(
Robin.
> To prevent this, jump directly to the buffer_head-based read function in
> KMSAN builds.
>
> Signed-off-by: Alexander Potapenko <glider@google.com>
> Cc: "Theodore Ts'o" <tytso@mit.edu>
> Cc: Andreas Dilger <adilger.kernel@dilger.ca>
> Cc: Vegard Nossum <vegard.nossum@oracle.com>
> Cc: Dmitry Vyukov <dvyukov@google.com>
> Cc: linux-mm@kvack.org
> ---
>
> Change-Id: I54ae8af536626a988e6398ff18a06c179b0ce034
> ---
> fs/ext4/readpage.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
> index a30b203fa461..a3bb9e3ce5de 100644
> --- a/fs/ext4/readpage.c
> +++ b/fs/ext4/readpage.c
> @@ -252,6 +252,17 @@ int ext4_mpage_readpages(struct address_space *mapping,
> if (page_has_buffers(page))
> goto confused;
>
> +#if defined(CONFIG_KMSAN)
> + /*
> + * The following code may treat adjacent pages allocated
> + * separately as a bigger contiguous allocation.
> + * KMSAN doesn't allow this, as the corresponding metadata
> + * pages may be separated.
> + * Skip this complex logic for KMSAN builds.
> + */
> + goto confused;
> +#endif
> +
> block_in_file = (sector_t)page->index << (PAGE_SHIFT - blkbits);
> last_block = block_in_file + nr_pages * blocks_per_page;
> last_block_in_file = (ext4_readpage_limit(inode) +
>
next prev parent reply other threads:[~2019-11-25 16:05 UTC|newest]
Thread overview: 120+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-22 11:25 [PATCH RFC v3 00/36] Add KernelMemorySanitizer infrastructure glider
2019-11-22 11:25 ` [PATCH RFC v3 01/36] stackdepot: check depot_index before accessing the stack slab glider
2019-11-27 14:22 ` Marco Elver
2019-11-22 11:25 ` [PATCH RFC v3 02/36] stackdepot: build with -fno-builtin glider
2019-11-27 14:22 ` Marco Elver
2019-11-22 11:25 ` [PATCH RFC v3 03/36] kasan: stackdepot: move filter_irq_stacks() to stackdepot.c glider
2019-11-27 14:22 ` Marco Elver
2019-11-27 14:56 ` Alexander Potapenko
2019-11-22 11:25 ` [PATCH RFC v3 04/36] stackdepot: reserve 5 extra bits in depot_stack_handle_t glider
2019-11-27 14:23 ` Marco Elver
2019-11-22 11:25 ` [PATCH RFC v3 05/36] kmsan: add ReST documentation glider
2019-11-27 14:22 ` Marco Elver
2019-12-03 12:42 ` Alexander Potapenko
2019-11-22 11:25 ` [PATCH RFC v3 06/36] kmsan: gfp: introduce __GFP_NO_KMSAN_SHADOW glider
2019-11-27 14:48 ` Marco Elver
2019-12-03 12:57 ` Alexander Potapenko
2019-11-22 11:25 ` [PATCH RFC v3 07/36] kmsan: introduce __no_sanitize_memory and __SANITIZE_MEMORY__ glider
2019-11-28 13:13 ` Marco Elver
2019-11-29 16:09 ` Andrey Konovalov
2019-12-16 11:35 ` Alexander Potapenko
2019-11-22 11:25 ` [PATCH RFC v3 08/36] kmsan: reduce vmalloc space glider
2019-11-28 13:30 ` Marco Elver
2019-11-22 11:25 ` [PATCH RFC v3 09/36] kmsan: add KMSAN bits to struct page and struct task_struct glider
2019-11-28 13:44 ` Marco Elver
2019-11-28 14:05 ` Alexander Potapenko
2019-11-22 11:25 ` [PATCH RFC v3 10/36] kmsan: add KMSAN runtime glider
2019-11-24 19:44 ` Wolfram Sang
2019-11-25 9:14 ` Alexander Potapenko
2019-11-29 16:07 ` Marco Elver
2019-12-19 14:16 ` Alexander Potapenko
2019-12-02 15:39 ` Andrey Konovalov
2019-12-20 18:58 ` Alexander Potapenko
2019-12-03 14:34 ` Andrey Konovalov
2019-11-22 11:25 ` [PATCH RFC v3 11/36] kmsan: stackdepot: don't allocate KMSAN metadata for stackdepot glider
2019-11-29 14:52 ` Andrey Konovalov
2019-12-03 14:27 ` Alexander Potapenko
2019-11-22 11:25 ` [PATCH RFC v3 12/36] kmsan: define READ_ONCE_NOCHECK() glider
2019-12-02 10:03 ` Marco Elver
2019-12-03 12:45 ` Alexander Potapenko
2019-11-22 11:25 ` [PATCH RFC v3 13/36] kmsan: make READ_ONCE_TASK_STACK() return initialized values glider
2019-12-02 10:07 ` Marco Elver
2019-12-05 15:52 ` Alexander Potapenko
2019-11-22 11:25 ` [PATCH RFC v3 14/36] kmsan: x86: sync metadata pages on page fault glider
2019-11-22 11:26 ` [PATCH RFC v3 15/36] kmsan: add tests for KMSAN glider
2019-11-29 14:14 ` Andrey Konovalov
2019-12-05 14:30 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 16/36] crypto: kmsan: disable accelerated configs under KMSAN glider
2019-12-02 13:25 ` Marco Elver
2019-12-05 14:51 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 17/36] kmsan: x86: disable UNWINDER_ORC " glider
2019-12-02 13:30 ` Marco Elver
2019-11-22 11:26 ` [PATCH RFC v3 18/36] kmsan: disable LOCK_DEBUGGING_SUPPORT glider
2019-12-02 13:33 ` Marco Elver
2019-12-03 14:34 ` Alexander Potapenko
2019-12-03 15:00 ` Qian Cai
2019-12-03 15:14 ` Alexander Potapenko
2019-12-03 18:02 ` Qian Cai
2019-12-03 18:38 ` Steven Rostedt
2019-12-04 8:41 ` Alexander Potapenko
2019-12-04 12:22 ` Petr Mladek
2019-12-04 13:12 ` Qian Cai
2019-12-04 16:24 ` Alexander Potapenko
2019-12-04 18:03 ` Qian Cai
2019-11-22 11:26 ` [PATCH RFC v3 20/36] kmsan: x86: increase stack sizes in KMSAN builds glider
2019-12-02 14:31 ` Marco Elver
2019-11-22 11:26 ` [PATCH RFC v3 21/36] kmsan: disable KMSAN instrumentation for certain kernel parts glider
2019-11-29 15:07 ` Andrey Konovalov
2019-12-10 10:35 ` Alexander Potapenko
2019-12-10 12:38 ` Alexander Potapenko
2019-12-10 12:43 ` Qian Cai
2019-11-22 11:26 ` [PATCH RFC v3 22/36] kmsan: mm: call KMSAN hooks from SLUB code glider
2019-12-02 15:36 ` Marco Elver
2019-12-10 12:07 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 23/36] kmsan: call KMSAN hooks where needed glider
2019-11-26 10:17 ` Petr Mladek
2019-11-26 10:52 ` Alexander Potapenko
2019-11-29 16:21 ` Andrey Konovalov
2019-12-16 11:30 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 24/36] kmsan: disable instrumentation of certain functions glider
2019-11-29 14:59 ` Andrey Konovalov
2019-12-18 10:02 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 25/36] kmsan: unpoison |tlb| in arch_tlb_gather_mmu() glider
2019-11-29 15:08 ` Andrey Konovalov
2019-12-03 14:19 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 26/36] kmsan: use __msan_memcpy() where possible glider
2019-11-29 15:13 ` Andrey Konovalov
2019-12-05 15:46 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 27/36] kmsan: hooks for copy_to_user() and friends glider
2019-11-29 15:34 ` Andrey Konovalov
2019-12-05 16:00 ` Alexander Potapenko
2019-12-05 16:44 ` Andrey Konovalov
2019-12-11 14:22 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 28/36] kmsan: enable KMSAN builds glider
2019-11-29 15:55 ` Andrey Konovalov
2019-12-11 12:51 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 29/36] kmsan: handle /dev/[u]random glider
2019-11-22 11:26 ` [PATCH RFC v3 30/36] kmsan: virtio: check/unpoison scatterlist in vring_map_one_sg() glider
2019-11-22 11:26 ` [PATCH RFC v3 31/36] kmsan: disable strscpy() optimization under KMSAN glider
2019-12-02 15:51 ` Marco Elver
2019-12-02 16:23 ` Alexander Potapenko
2019-12-03 11:19 ` Alexander Potapenko
2019-12-03 11:24 ` Marco Elver
2019-12-03 11:27 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 32/36] kmsan: add iomap support glider
2019-12-03 12:50 ` Marco Elver
2019-12-03 14:07 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 33/36] kmsan: dma: unpoison memory mapped by dma_direct_map_page() glider
2019-11-22 11:26 ` [PATCH RFC v3 34/36] kmsan: disable physical page merging in biovec glider
2019-12-03 12:54 ` Marco Elver
2019-12-03 13:38 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 35/36] kmsan: ext4: skip block merging logic in ext4_mpage_readpages for KMSAN glider
2019-11-25 16:05 ` Robin Murphy [this message]
2019-11-25 17:03 ` Alexander Potapenko
2019-12-03 14:22 ` Marco Elver
2019-12-05 14:31 ` Alexander Potapenko
2019-11-22 11:26 ` [PATCH RFC v3 36/36] net: kasan: kmsan: support CONFIG_GENERIC_CSUM on x86, enable it for KASAN/KMSAN glider
2019-12-03 14:17 ` Marco Elver
2019-12-05 14:37 ` Alexander Potapenko
2019-11-29 14:39 ` [PATCH RFC v3 00/36] Add KernelMemorySanitizer infrastructure Marco Elver
2019-12-02 16:02 ` Alexander Potapenko
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