linux-kernel - [tip:perf/core] perf/core: Fix the address filtering fix

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Message-ID: <tip-52a44f83fc2d64a5e74d5d685fad2fecc7b7a321@git.kernel.org>
Date:   Tue, 16 Apr 2019 04:31:02 -0700
From:   tip-bot for Alexander Shishkin <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     eranian@...gle.com, jolsa@...hat.com,
        torvalds@...ux-foundation.org, mingo@...nel.org,
        linux-kernel@...r.kernel.org, acme@...hat.com,
        alexander.shishkin@...ux.intel.com, peterz@...radead.org,
        vincent.weaver@...ne.edu, hpa@...or.com, adrian.hunter@...el.com,
        tglx@...utronix.de
Subject: [tip:perf/core] perf/core: Fix the address filtering fix

Commit-ID:  52a44f83fc2d64a5e74d5d685fad2fecc7b7a321
Gitweb:     https://git.kernel.org/tip/52a44f83fc2d64a5e74d5d685fad2fecc7b7a321
Author:     Alexander Shishkin <alexander.shishkin@...ux.intel.com>
AuthorDate: Fri, 29 Mar 2019 11:12:12 +0200
Committer:  Ingo Molnar <mingo@...nel.org>
CommitDate: Tue, 16 Apr 2019 12:13:57 +0200

perf/core: Fix the address filtering fix

The following recent commit:

  c60f83b813e5 ("perf, pt, coresight: Fix address filters for vmas with non-zero offset")

changes the address filtering logic to communicate filter ranges to the PMU driver
via a single address range object, instead of having the driver do the final bit of
math.

That change forgets to take into account kernel filters, which are not calculated
the same way as DSO based filters.

Fix that by passing the kernel filters the same way as file-based filters.
This doesn't require any additional changes in the drivers.

Reported-by: Adrian Hunter <adrian.hunter@...el.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
Cc: Arnaldo Carvalho de Melo <acme@...hat.com>
Cc: Jiri Olsa <jolsa@...hat.com>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Vince Weaver <vincent.weaver@...ne.edu>
Fixes: c60f83b813e5 ("perf, pt, coresight: Fix address filters for vmas with non-zero offset")
Link: https://lkml.kernel.org/r/20190329091212.29870-1-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@...nel.org>
---
 kernel/events/core.c | 37 +++++++++++++++++++++----------------
 1 file changed, 21 insertions(+), 16 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 534e01e7bc36..dc7dead2d2cc 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9077,26 +9077,29 @@ static void perf_event_addr_filters_apply(struct perf_event *event)
 	if (task == TASK_TOMBSTONE)
 		return;
 
-	if (!ifh->nr_file_filters)
-		return;
-
-	mm = get_task_mm(event->ctx->task);
-	if (!mm)
-		goto restart;
+	if (ifh->nr_file_filters) {
+		mm = get_task_mm(event->ctx->task);
+		if (!mm)
+			goto restart;
 
-	down_read(&mm->mmap_sem);
+		down_read(&mm->mmap_sem);
+	}
 
 	raw_spin_lock_irqsave(&ifh->lock, flags);
 	list_for_each_entry(filter, &ifh->list, entry) {
-		event->addr_filter_ranges[count].start = 0;
-		event->addr_filter_ranges[count].size = 0;
+		if (filter->path.dentry) {
+			/*
+			 * Adjust base offset if the filter is associated to a
+			 * binary that needs to be mapped:
+			 */
+			event->addr_filter_ranges[count].start = 0;
+			event->addr_filter_ranges[count].size = 0;
 
-		/*
-		 * Adjust base offset if the filter is associated to a binary
-		 * that needs to be mapped:
-		 */
-		if (filter->path.dentry)
 			perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
+		} else {
+			event->addr_filter_ranges[count].start = filter->offset;
+			event->addr_filter_ranges[count].size  = filter->size;
+		}
 
 		count++;
 	}
@@ -9104,9 +9107,11 @@ static void perf_event_addr_filters_apply(struct perf_event *event)
 	event->addr_filters_gen++;
 	raw_spin_unlock_irqrestore(&ifh->lock, flags);
 
-	up_read(&mm->mmap_sem);
+	if (ifh->nr_file_filters) {
+		up_read(&mm->mmap_sem);
 
-	mmput(mm);
+		mmput(mm);
+	}
 
 restart:
 	perf_event_stop(event, 1);