[merged] mm-damon-dbgfs-fix-struct-pid-leaks-in-dbgfs_target_ids_write.patch removed from -mm tree

[merged] mm-damon-dbgfs-fix-struct-pid-leaks-in-dbgfs_target_ids_write.patch removed from -mm tree

[akpm]

The patch titled
     Subject: mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()'
has been removed from the -mm tree.  Its filename was
     mm-damon-dbgfs-fix-struct-pid-leaks-in-dbgfs_target_ids_write.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: SeongJae Park <sj@kernel.org>
Subject: mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()'

DAMON debugfs interface increases the reference counts of 'struct pid's
for targets from the 'target_ids' file write callback
('dbgfs_target_ids_write()'), but decreases the counts only in DAMON
monitoring termination callback ('dbgfs_before_terminate()').

Therefore, when 'target_ids' file is repeatedly written without DAMON
monitoring start/termination, the reference count is not decreased and
therefore memory for the 'struct pid' cannot be freed.  This commit fixes
this issue by decreasing the reference counts when 'target_ids' is
written.

Link: https://lkml.kernel.org/r/20211229124029.23348-1-sj@kernel.org
Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/damon/dbgfs.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

--- a/mm/damon/dbgfs.c~mm-damon-dbgfs-fix-struct-pid-leaks-in-dbgfs_target_ids_write
+++ a/mm/damon/dbgfs.c
@@ -353,6 +353,7 @@ static ssize_t dbgfs_target_ids_write(st
 		const char __user *buf, size_t count, loff_t *ppos)
 {
 	struct damon_ctx *ctx = file->private_data;
+	struct damon_target *t, *next_t;
 	bool id_is_pid = true;
 	char *kbuf, *nrs;
 	unsigned long *targets;
@@ -397,8 +398,12 @@ static ssize_t dbgfs_target_ids_write(st
 		goto unlock_out;
 	}
 
-	/* remove targets with previously-set primitive */
-	damon_set_targets(ctx, NULL, 0);
+	/* remove previously set targets */
+	damon_for_each_target_safe(t, next_t, ctx) {
+		if (targetid_is_pid(ctx))
+			put_pid((struct pid *)t->id);
+		damon_destroy_target(t);
+	}
 
 	/* Configure the context for the address space type */
 	if (id_is_pid)
_

Patches currently in -mm which might be from sj@kernel.org are

mm-damon-remove-some-no-need-func-definitions-in-damonh-file-fix.patch
mm-damon-convert-macro-functions-to-static-inline-functions.patch
docs-admin-guide-mm-damon-usage-update-for-scheme-quotas-and-watermarks.patch
docs-admin-guide-mm-damon-usage-remove-redundant-information.patch
docs-admin-guide-mm-damon-usage-mention-tracepoint-at-the-beginning.patch
docs-admin-guide-mm-damon-usage-update-for-kdamond_pid-and-mkrm_contexts.patch
mm-damon-remove-a-mistakenly-added-comment-for-a-future-feature.patch
mm-damon-schemes-account-scheme-actions-that-successfully-applied.patch
mm-damon-schemes-account-how-many-times-quota-limit-has-exceeded.patch
mm-damon-reclaim-provide-reclamation-statistics.patch
docs-admin-guide-mm-damon-reclaim-document-statistics-parameters.patch
mm-damon-dbgfs-support-all-damos-stats.patch
docs-admin-guide-mm-damon-usage-update-for-schemes-statistics.patch
mm-damon-dbgfs-remove-a-unnecessary-variable.patch
mm-damon-vaddr-use-pr_debug-for-damon_va_three_regions-failure-logging.patch
mm-damon-vaddr-hide-kernel-pointer-from-damon_va_three_regions-failure-log.patch
mm-damon-hide-kernel-pointer-from-tracepoint-event.patch