From: David Laight <David.Laight@ACULAB.COM>
To: 'Numfor Mbiziwo-Tiapo' <nums@google.com>,
"peterz@infradead.org" <peterz@infradead.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"acme@kernel.org" <acme@kernel.org>,
"alexander.shishkin@linux.intel.com"
<alexander.shishkin@linux.intel.com>,
"jolsa@redhat.com" <jolsa@redhat.com>,
"namhyung@kernel.org" <namhyung@kernel.org>,
"songliubraving@fb.com" <songliubraving@fb.com>,
"mbd@fb.com" <mbd@fb.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"irogers@google.com" <irogers@google.com>,
"eranian@google.com" <eranian@google.com>
Subject: RE: [PATCH 3/3] Fix insn.c misaligned address error
Date: Thu, 25 Jul 2019 13:06:32 +0000 [thread overview]
Message-ID: <c256d9b6702b4d37a0c21b93f319b476@AcuMS.aculab.com> (raw)
In-Reply-To: <20190724184512.162887-4-nums@google.com>
From: Numfor Mbiziwo-Tiapo
> Sent: 24 July 2019 19:45
>
> The ubsan (undefined behavior sanitizer) version of perf throws an
> error on the 'x86 instruction decoder - new instructions' function
> of perf test.
>
> To reproduce this run:
> make -C tools/perf USE_CLANG=1 EXTRA_CFLAGS="-fsanitize=undefined"
>
> then run: tools/perf/perf test 62 -v
>
> The error occurs in the __get_next macro (line 34) where an int is
> read from a potentially unaligned address. Using memcpy instead of
> assignment from an unaligned pointer.
...
> #define __get_next(t, insn) \
> - ({ t r = *(t*)insn->next_byte; insn->next_byte += sizeof(t); r; })
> + ({ t r; memcpy(&r, insn->next_byte, sizeof(t)); \
> + insn->next_byte += sizeof(t); r; })
Isn't there a get_unaligned_u32() (or similar) that can be used?
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2019-07-25 13:06 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-24 18:45 [PATCH 0/3] Perf UBsan Patches Numfor Mbiziwo-Tiapo
2019-07-24 18:45 ` [PATCH 1/3] Fix backward-ring-buffer.c format-truncation error Numfor Mbiziwo-Tiapo
2019-07-25 13:08 ` David Laight
2019-07-26 19:40 ` Arnaldo Carvalho de Melo
2019-07-29 20:57 ` [PATCH v2] Fix annotate.c use of uninitialized value error Numfor Mbiziwo-Tiapo
2019-08-07 11:32 ` Jiri Olsa
2019-10-25 22:11 ` Ian Rogers
2020-07-09 0:54 ` Ian Rogers
2020-07-09 15:38 ` Arnaldo Carvalho de Melo
2019-07-24 18:45 ` [PATCH 2/3] Fix ordered-events.c array-bounds error Numfor Mbiziwo-Tiapo
2019-07-26 19:33 ` Arnaldo Carvalho de Melo
2019-07-26 19:35 ` Arnaldo Carvalho de Melo
2019-07-24 18:45 ` [PATCH 3/3] Fix insn.c misaligned address error Numfor Mbiziwo-Tiapo
2019-07-25 13:06 ` David Laight [this message]
2019-07-25 21:18 ` Ian Rogers
2019-07-26 19:38 ` Arnaldo Carvalho de Melo
2019-07-27 9:46 ` Masami Hiramatsu
2019-07-29 8:22 ` Adrian Hunter
2019-07-29 19:32 ` Ian Rogers
2019-07-30 7:50 ` Adrian Hunter
2019-07-30 0:47 ` Masami Hiramatsu
2019-07-30 7:53 ` Adrian Hunter
2019-07-30 9:17 ` David Laight
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