kernel/linux.git/mm/damon, branch v6.1.168

mm/damon/sysfs: check contexts->nr before accessing contexts_arr[0]

2026-04-11T12:16:33+00:00

Multiple sysfs command paths dereference contexts_arr[0] without first verifying that kdamond->contexts->nr == 1. A user can set nr_contexts to 0 via sysfs while DAMON is running, causing NULL pointer dereferences. In more detail, the issue can be triggered by privileged users like below. First, start DAMON and make contexts directory empty (kdamond->contexts->nr == 0). # damo start # cd /sys/kernel/mm/damon/admin/kdamonds/0 # echo 0 > contexts/nr_contexts Then, each of below commands will cause the NULL pointer dereference. # echo update_schemes_stats > state # echo update_schemes_tried_regions > state # echo update_schemes_tried_bytes > state # echo update_schemes_effective_quotas > state # echo update_tuned_intervals > state Guard all commands (except OFF) at the entry point of damon_sysfs_handle_cmd(). (cherry picked from commit 1bfe9fb5ed2667fb075682408b776b5273162615) Link: https://lkml.kernel.org/r/20260321175427.86000-3-sj@kernel.org Fixes: 0ac32b8affb5 ("mm/damon/sysfs: support DAMOS stats") Signed-off-by: Josh Law Reviewed-by: SeongJae Park Signed-off-by: SeongJae Park Cc: [5.18+] Signed-off-by: Andrew Morton Signed-off-by: SeongJae Park Signed-off-by: Sasha Levin

mm/damon/sysfs-scheme: cleanup access_pattern subdirs on scheme dir setup failure

2026-02-06T15:44:14+00:00

commit 392b3d9d595f34877dd745b470c711e8ebcd225c upstream. When a DAMOS-scheme DAMON sysfs directory setup fails after setup of access_pattern/ directory, subdirectories of access_pattern/ directory are not cleaned up. As a result, DAMON sysfs interface is nearly broken until the system reboots, and the memory for the unremoved directory is leaked. Cleanup the directories under such failures. Link: https://lkml.kernel.org/r/20251225023043.18579-5-sj@kernel.org Fixes: 9bbb820a5bd5 ("mm/damon/sysfs: support DAMOS quotas") Signed-off-by: SeongJae Park Cc: chongjiapeng Cc: # 5.18.x Signed-off-by: Andrew Morton Signed-off-by: SeongJae Park Signed-off-by: Greg Kroah-Hartman

mm/damon/sysfs-scheme: cleanup quotas subdirs on scheme dir setup failure

2026-02-06T15:44:14+00:00

commit dc7e1d75fd8c505096d0cddeca9e2efb2b55aaf9 upstream. When a DAMOS-scheme DAMON sysfs directory setup fails after setup of quotas/ directory, subdirectories of quotas/ directory are not cleaned up. As a result, DAMON sysfs interface is nearly broken until the system reboots, and the memory for the unremoved directory is leaked. Cleanup the directories under such failures. Link: https://lkml.kernel.org/r/20251225023043.18579-4-sj@kernel.org Fixes: 1b32234ab087 ("mm/damon/sysfs: support DAMOS watermarks") Signed-off-by: SeongJae Park Cc: chongjiapeng Cc: # 5.18.x Signed-off-by: Andrew Morton Signed-off-by: SeongJae Park Signed-off-by: Greg Kroah-Hartman

mm/damon/sysfs: cleanup attrs subdirs on context dir setup failure

2026-02-06T15:44:00+00:00

commit 9814cc832b88bd040fc2a1817c2b5469d0f7e862 upstream. When a context DAMON sysfs directory setup is failed after setup of attrs/ directory, subdirectories of attrs/ directory are not cleaned up. As a result, DAMON sysfs interface is nearly broken until the system reboots, and the memory for the unremoved directory is leaked. Cleanup the directories under such failures. Link: https://lkml.kernel.org/r/20251225023043.18579-3-sj@kernel.org Fixes: c951cd3b8901 ("mm/damon: implement a minimal stub for sysfs-based DAMON interface") Signed-off-by: SeongJae Park Cc: chongjiapeng Cc: # 5.18.x Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/damon/tests/core-kunit: handle alloc failures in damon_test_set_regions()

2026-01-11T14:19:14+00:00

commit 74d5969995d129fd59dd93b9c7daa6669cb6810f upstream. damon_test_set_regions() is assuming all dynamic memory allocation in it will succeed. Those are indeed likely in the real use cases since those allocations are too small to fail, but theoretically those could fail. In the case, inappropriate memory access can happen. Fix it by appropriately cleanup pre-allocated memory and skip the execution of the remaining tests in the failure cases. Link: https://lkml.kernel.org/r/20251101182021.74868-11-sj@kernel.org Fixes: 62f409560eb2 ("mm/damon/core-test: test damon_set_regions") Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: David Gow Cc: Kefeng Wang Cc: [6.1+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/damon/tests/core-kunit: handle memory alloc failure from damon_test_aggregate()

2026-01-11T14:19:14+00:00

commit f79f2fc44ebd0ed655239046be3e80e8804b5545 upstream. damon_test_aggregate() is assuming all dynamic memory allocation in it will succeed. Those are indeed likely in the real use cases since those allocations are too small to fail, but theoretically those could fail. In the case, inappropriate memory access can happen. Fix it by appropriately cleanup pre-allocated memory and skip the execution of the remaining tests in the failure cases. Link: https://lkml.kernel.org/r/20251101182021.74868-5-sj@kernel.org Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: David Gow Cc: Kefeng Wang Cc: [5.15+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/damon/tests/core-kunit: handle alloc failures on damon_test_split_regions_of()

2026-01-11T14:19:14+00:00

commit eded254cb69044bd4abde87394ea44909708d7c0 upstream. damon_test_split_regions_of() is assuming all dynamic memory allocation in it will succeed. Those are indeed likely in the real use cases since those allocations are too small to fail, but theoretically those could fail. In the case, inappropriate memory access can happen. Fix it by appropriately cleanup pre-allocated memory and skip the execution of the remaining tests in the failure cases. Link: https://lkml.kernel.org/r/20251101182021.74868-9-sj@kernel.org Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: David Gow Cc: Kefeng Wang Cc: [5.15+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/damon/tests/core-kunit: handle memory failure from damon_test_target()

2026-01-11T14:19:14+00:00

commit fafe953de2c661907c94055a2497c6b8dbfd26f3 upstream. damon_test_target() is assuming all dynamic memory allocation in it will succeed. Those are indeed likely in the real use cases since those allocations are too small to fail, but theoretically those could fail. In the case, inappropriate memory access can happen. Fix it by appropriately cleanup pre-allocated memory and skip the execution of the remaining tests in the failure cases. Link: https://lkml.kernel.org/r/20251101182021.74868-4-sj@kernel.org Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: David Gow Cc: Kefeng Wang Cc: [5.15+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/damon/tests/core-kunit: handle alloc failures on damon_test_merge_two()

2026-01-11T14:19:14+00:00

commit 3d443dd29a1db7efa587a4bb0c06a497e13ca9e4 upstream. damon_test_merge_two() is assuming all dynamic memory allocation in it will succeed. Those are indeed likely in the real use cases since those allocations are too small to fail, but theoretically those could fail. In the case, inappropriate memory access can happen. Fix it by appropriately cleanup pre-allocated memory and skip the execution of the remaining tests in the failure cases. Link: https://lkml.kernel.org/r/20251101182021.74868-7-sj@kernel.org Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: David Gow Cc: Kefeng Wang Cc: [5.15+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman

mm/damon/tests/core-kunit: handle alloc failures on dasmon_test_merge_regions_of()

2026-01-11T14:19:14+00:00

commit 0998d2757218771c59d5ca59ccf13d1542a38f17 upstream. damon_test_merge_regions_of() is assuming all dynamic memory allocation in it will succeed. Those are indeed likely in the real use cases since those allocations are too small to fail, but theoretically those could fail. In the case, inappropriate memory access can happen. Fix it by appropriately cleanup pre-allocated memory and skip the execution of the remaining tests in the failure cases. Link: https://lkml.kernel.org/r/20251101182021.74868-8-sj@kernel.org Fixes: 17ccae8bb5c9 ("mm/damon: add kunit tests") Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: David Gow Cc: Kefeng Wang Cc: [5.15+] Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman