6.6-stable review patch. If anyone has any objections, please let me know.
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From: SeongJae Park sj@kernel.org
commit 4f489fe6afb395dbc79840efa3c05440b760d883 upstream.
memcg_path_store() assigns a newly allocated memory buffer to filter->memcg_path, without deallocating the previously allocated and assigned memory buffer. As a result, users can leak kernel memory by continuously writing a data to memcg_path DAMOS sysfs file. Fix the leak by deallocating the previously set memory buffer.
Link: https://lkml.kernel.org/r/20250619183608.6647-2-sj@kernel.org Fixes: 7ee161f18b5d ("mm/damon/sysfs-schemes: implement filter directory") Signed-off-by: SeongJae Park sj@kernel.org Cc: Shuah Khan shuah@kernel.org Cc: stable@vger.kernel.org [6.3.x] Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- mm/damon/sysfs-schemes.c | 1 + 1 file changed, 1 insertion(+)
--- a/mm/damon/sysfs-schemes.c +++ b/mm/damon/sysfs-schemes.c @@ -376,6 +376,7 @@ static ssize_t memcg_path_store(struct k return -ENOMEM;
strscpy(path, buf, count + 1); + kfree(filter->memcg_path); filter->memcg_path = path; return count; }