[tip:perf/urgent] perf/x86/intel/pt: Fix an off-by-one in address filter configuration

From: tip-bot for Alexander Shishkin
Date: Fri Sep 16 2016 - 07:58:57 EST

Commit-ID: 95f60084acbcee6c466256cf26eb52191fad9edc
Gitweb: http://git.kernel.org/tip/95f60084acbcee6c466256cf26eb52191fad9edc
Author: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
AuthorDate: Thu, 15 Sep 2016 18:13:50 +0300
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Fri, 16 Sep 2016 11:14:16 +0200

perf/x86/intel/pt: Fix an off-by-one in address filter configuration

PT address filter configuration requires that a range is specified by
its first and last address, but at the moment we're obtaining the end
of the range by adding user specified size to its start, which is off
by one from what it actually needs to be.

Fix this and make sure that zero-sized filters don't pass the filter

Reported-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Acked-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vince Weaver <vincent.weaver@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v4.7
Cc: stable@xxxxxxxxxxxxxxx#v4.7
Cc: vince@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20160915151352.21306-2-alexander.shishkin@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
arch/x86/events/intel/pt.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c
index 04bb5fb..5ec0100 100644
--- a/arch/x86/events/intel/pt.c
+++ b/arch/x86/events/intel/pt.c
@@ -1081,7 +1081,7 @@ static int pt_event_addr_filters_validate(struct list_head *filters)

list_for_each_entry(filter, filters, entry) {
/* PT doesn't support single address triggers */
- if (!filter->range)
+ if (!filter->range || !filter->size)

if (!filter->inode && !kernel_ip(filter->offset))
@@ -1111,7 +1111,7 @@ static void pt_event_addr_filters_sync(struct perf_event *event)
} else {
/* apply the offset */
msr_a = filter->offset + offs[range];
- msr_b = filter->size + msr_a;
+ msr_b = filter->size + msr_a - 1;

filters->filter[range].msr_a = msr_a;