From: glider@google.com To: Vegard Nossum <vegard.nossum@oracle.com>, Dmitry Vyukov <dvyukov@google.com>, Sergey Senozhatsky <sergey.senozhatsky@gmail.com>, Arnd Bergmann <arnd@arndb.de>, Andrey Ryabinin <aryabinin@virtuozzo.com>, linux-mm@kvack.org Cc: glider@google.com, viro@zeniv.linux.org.uk, adilger.kernel@dilger.ca, akpm@linux-foundation.org, andreyknvl@google.com, luto@kernel.org, ard.biesheuvel@linaro.org, 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, robin.murphy@arm.com, rostedt@goodmis.org, tiwai@suse.com, tytso@mit.edu, tglx@linutronix.de, gor@linux.ibm.com, wsa@the-dreams.de Subject: [PATCH RFC v3 02/36] stackdepot: build with -fno-builtin Date: Fri, 22 Nov 2019 12:25:47 +0100 Message-ID: <20191122112621.204798-3-glider@google.com> (raw) In-Reply-To: <20191122112621.204798-1-glider@google.com> Clang may replace stackdepot_memcmp() with a call to instrumented bcmp(), which is exactly what we wanted to avoid creating stackdepot_memcmp(). Building the file with -fno-builtin prevents such optimizations. Signed-off-by: Alexander Potapenko <glider@google.com> To: Alexander Potapenko <glider@google.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Cc: linux-mm@kvack.org --- This patch was previously called "stackdepot: prevent Clang from optimizing away stackdepot_memcmp()". v3: - use -fno-builtin instead of a barrier Change-Id: I4495b617b15c0ab003a61c1f0d54d0026fa8b144 --- lib/Makefile | 4 ++++ lib/stackdepot.c | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-) diff --git a/lib/Makefile b/lib/Makefile index c5892807e06f..58a3e1b1a868 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -215,6 +215,10 @@ obj-$(CONFIG_SG_POOL) += sg_pool.o obj-$(CONFIG_STMP_DEVICE) += stmp_device.o obj-$(CONFIG_IRQ_POLL) += irq_poll.o +# stackdepot.c should not be instrumented or call instrumented functions. +# Prevent the compiler from calling builtins like memcmp() or bcmp() from this +# file. +CFLAGS_stackdepot.o += -fno-builtin obj-$(CONFIG_STACKDEPOT) += stackdepot.o KASAN_SANITIZE_stackdepot.o := n KCOV_INSTRUMENT_stackdepot.o := n diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 0bc6182bc7a6..6d1123123e56 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -163,7 +163,7 @@ int stackdepot_memcmp(const unsigned long *u1, const unsigned long *u2, unsigned int n) { for ( ; n-- ; u1++, u2++) { - if (*u1 != *u2) + if ((*u1) != (*u2)) return 1; } return 0; -- 2.24.0.432.g9d3f5f5b63-goog
next prev parent reply index 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 ` glider [this message] 2019-11-27 14:22 ` [PATCH RFC v3 02/36] stackdepot: build with -fno-builtin 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 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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