mm/damon/sysfs: catch commit test ctx alloc failure

commit f0c5118ebb0eb7e4fd6f0d2ace3315ca141b317f upstream.

Patch series "mm/damon/sysfs: fix commit test damon_ctx [de]allocation".

DAMON sysfs interface dynamically allocates and uses a damon_ctx object
for testing if given inputs for online DAMON parameters update is valid.
The object is being used without an allocation failure check, and leaked
when the test succeeds.  Fix the two bugs.

This patch (of 2):

The damon_ctx for testing online DAMON parameters commit inputs is used
without its allocation failure check.  This could result in an invalid
memory access.  Fix it by directly returning an error when the allocation
failed.

Link: https://lkml.kernel.org/r/20251003201455.41448-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20251003201455.41448-2-sj@kernel.org
Fixes: 4c9ea539ad59 ("mm/damon/sysfs: validate user inputs from damon_sysfs_commit_input()")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org>	[6.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index 7308dee97b21097305c9b615da5d6d058b0a0ba1..5a4c0a2067b256f5af108b0f91d2c39da168c9af 100644 (file)
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1435,6 +1435,8 @@ static int damon_sysfs_commit_input(void *data)
        if (IS_ERR(param_ctx))
                return PTR_ERR(param_ctx);
        test_ctx = damon_new_ctx();
+       if (!test_ctx)
+               return -ENOMEM;
        err = damon_commit_ctx(test_ctx, param_ctx);
        if (err) {
                damon_destroy_ctx(test_ctx);