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SubjectRe: [PATCH v2 3/4] perf tests: stop reading if objdump output crossed sections
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On 02/09/15 11:19, Jan Stancek wrote:
> objdump output can span across multiple sections:
>
> Disassembly of section .text:
> 0000000000000008 <crc32c+0x8>:
> 8: 48 89 e5 mov %rsp,%rbp
> b: 53 push %rbx
> c: 8b 01 mov (%rcx),%eax
> <snip>
> 6b: 90 nop
>
> Disassembly of section .init.text:
> 0000000000000008 <init_module+0x8>:
> 8: 00 00 add %al,(%rax)
> a: 00 00 add %al,(%rax)
> c: 48 89 e5
>
> Stop further reading if address starts going backwards,
> assuming we crossed sections.
>
> Signed-off-by: Jan Stancek <jstancek@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: David Ahern <dsahern@gmail.com>
> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>


Acked-by: Adrian Hunter <adrian.hunter@intel.com>


> ---
> tools/perf/tests/code-reading.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
> index 375ba30e4ed0..e6bf47ff7e91 100644
> --- a/tools/perf/tests/code-reading.c
> +++ b/tools/perf/tests/code-reading.c
> @@ -79,7 +79,7 @@ static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
> size_t line_len, off_last = 0;
> ssize_t ret;
> int err = 0;
> - u64 addr;
> + u64 addr, last_addr = start_addr;
>
> while (off_last < *len) {
> size_t off, read_bytes, written_bytes;
> @@ -101,6 +101,11 @@ static int read_objdump_output(FILE *f, void *buf, size_t *len, u64 start_addr)
>
> if (sscanf(line, "%"PRIx64, &addr) != 1)
> continue;
> + if (addr < last_addr) {
> + pr_debug("addr going backwards, read beyond section?\n");
> + break;
> + }
> + last_addr = addr;
>
> /* copy it from temporary buffer to 'buf' according
> * to address on current objdump line */
>



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