From: Josh Law <objecting@objecting.org>
To: sj@kernel.org, akpm@linux-foundation.org
Cc: damon@lists.linux.dev, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Josh Law <objecting@objecting.org>
Subject: [PATCH 2/4] mm/damon/sysfs: check contexts->nr before clear_schemes_tried_regions
Date: Thu, 19 Mar 2026 15:57:40 +0000 [thread overview]
Message-ID: <20260319155742.186627-3-objecting@objecting.org> (raw)
In-Reply-To: <20260319155742.186627-1-objecting@objecting.org>
The CLEAR_SCHEMES_TRIED_REGIONS command accesses contexts_arr[0]
without verifying nr_contexts >= 1, causing a NULL pointer dereference
when no context is configured. Add the missing check.
Signed-off-by: Josh Law <objecting@objecting.org>
---
mm/damon/sysfs.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index b573b9d60784..36ad2e8956c9 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1769,6 +1769,8 @@ static int damon_sysfs_handle_cmd(enum damon_sysfs_cmd cmd,
case DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS:
return damon_sysfs_update_schemes_tried_regions(kdamond, false);
case DAMON_SYSFS_CMD_CLEAR_SCHEMES_TRIED_REGIONS:
+ if (kdamond->contexts->nr != 1)
+ return -EINVAL;
return damon_sysfs_schemes_clear_regions(
kdamond->contexts->contexts_arr[0]->schemes);
case DAMON_SYSFS_CMD_UPDATE_SCHEMES_EFFECTIVE_QUOTAS:
--
2.34.1
next prev parent reply other threads:[~2026-03-19 15:58 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-19 15:57 [PATCH 0/4] mm/damon/sysfs: fix resource leak and NULL pointer dereferences Josh Law
2026-03-19 15:57 ` [PATCH 1/4] mm/damon/sysfs: fix param_ctx leak on damon_sysfs_new_test_ctx() failure Josh Law
2026-03-20 2:00 ` SeongJae Park
2026-03-19 15:57 ` Josh Law [this message]
2026-03-20 2:13 ` [PATCH 2/4] mm/damon/sysfs: check contexts->nr before clear_schemes_tried_regions SeongJae Park
2026-03-20 7:06 ` Josh Law
2026-03-20 14:47 ` SeongJae Park
2026-03-20 15:14 ` Josh Law
2026-03-20 15:51 ` SeongJae Park
2026-03-20 15:56 ` Josh Law
2026-03-19 15:57 ` [PATCH 3/4] mm/damon/sysfs: check contexts->nr in update_schemes_tried_regions Josh Law
2026-03-20 2:15 ` SeongJae Park
2026-03-19 15:57 ` [PATCH 4/4] mm/damon/sysfs: check contexts->nr in repeat_call_fn Josh Law
2026-03-20 2:06 ` SeongJae Park
2026-03-19 19:24 ` [PATCH 0/4] mm/damon/sysfs: fix resource leak and NULL pointer dereferences Josh Law
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