[PATCH v1 1/3] perf/x86/intel/pt: Fix an off-by-one in address filter configuration

[Alexander Shishkin]

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
validation.

Cc: stable@xxxxxxxxxxxxxxx # v4.7
Reported-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
---
 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 04bb5fb5a8..5ec0100e3f 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)
 			return -EOPNOTSUPP;
 
 		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;
-- 
2.9.3