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SubjectRe: [PATCH] perf probe: Restrict user to use only one executable with -V
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Oops! this will disable support for multiple functions from single
binary. (-x binary -V fun1 -V fun2)

Sorry for the noise. Please ignore the patch. Will revise it.

Thanks,
Ravi

On Thursday 26 October 2017 01:21 PM, Ravi Bangoria wrote:
> If multiple executables (-x) are specified with 'perf probe',
> listing variables only considers first executable. Ex,
>
> $ perf probe -V do_sys_open -x ./test -V fun
> Failed to find debug information for address 40
> Debuginfo analysis failed.
> Error: Failed to show vars.
> Available variables at do_sys_open
> @<do_sys_open+0>
> char* filename
> int dfd
> int flags
> struct open_flags op
> umode_t mode
>
> Here, first executable is kernel and second is 'test'. Instead
> of finding 'fun()' from 'test', perf is looking for 'fun()' in
> kernel. Fix this by restricting user to use only one executable
> with -V.
>
> $ perf probe -V do_sys_open -x ./test -V fun
> Error: Multiple executables are not allowed.
>
> $ perf probe -V do_sys_open
> Available variables at do_sys_open
> @<do_sys_open+0>
> char* filename
> int dfd
> int flags
> struct open_flags op
> umode_t mode
>
> $ perf probe -x ./test -V fun
> Available variables at fun
> @<fun+0>
> int arg
>
> Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> ---
> tools/perf/util/probe-event.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index b7aaf9b..0e04015 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -1128,6 +1128,11 @@ int show_available_vars(struct perf_probe_event *pevs, int npevs,
> int i, ret = 0;
> struct debuginfo *dinfo;
>
> + if (npevs > 1) {
> + pr_err("Error: Multiple executables are not allowed.\n");
> + return 0;
> + }
> +
> ret = init_probe_symbol_maps(pevs->uprobes);
> if (ret < 0)
> return ret;

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