selftests/mm: free dynamically allocated PMD-sized buffers in split_huge_page_test

Dynamically allocated buffers of PMD size for file-backed THP operations
(file_buf1 and file_buf2) were not freed on the success path and some
failure paths.  Since the function is called repeatedly in a loop for each
split order, this can cause significant memory leaks.

On architectures with large PMD sizes, repeated leaks could exhaust system
memory and trigger the OOM killer during test execution.

Ensure all allocated buffers are freed to maintain stable repeated test
runs.

Link: https://lore.kernel.org/060c673b376bbeeed2b1fb1d48a825e846654191.1779296493.git.sayalip@linux.ibm.com
Fixes: 035a112e5fd5 ("selftests/mm: make file-backed THP split work by writing PMD size data")
Signed-off-by: Sayali Patil <sayalip@linux.ibm.com>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Cc: David Hildenbrand (Arm) <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: "Ritesh Harjani (IBM)" <ritesh.list@gmail.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c
index 9a50557069ad276ee2e312dcced61ae66e854d0f..32b991472f744f1193e9b4e455bf26620192d104 100644 (file)
--- a/tools/testing/selftests/mm/split_huge_page_test.c
+++ b/tools/testing/selftests/mm/split_huge_page_test.c
@@ -473,12 +473,15 @@ static void split_file_backed_thp(int order)
        unsigned long size = 2 * pmd_pagesize;
        char opts[64];
        ssize_t num_written, num_read;
-       char *file_buf1, *file_buf2;
+       char *file_buf1 = NULL, *file_buf2 = NULL;
        uint64_t pgoff_start = 0, pgoff_end = 1024;
        int i;
 
        ksft_print_msg("Please enable pr_debug in split_huge_pages_in_file() for more info.\n");
 
+       if (!tmpfs_loc)
+               ksft_exit_fail_msg("mkdtemp failed\n");
+
        file_buf1 = (char *)malloc(pmd_pagesize);
        file_buf2 = (char *)malloc(pmd_pagesize);
 
@@ -494,8 +497,10 @@ static void split_file_backed_thp(int order)
        snprintf(opts, sizeof(opts), "huge=always,size=%lu", size);
        status = mount("tmpfs", tmpfs_loc, "tmpfs", 0, opts);
 
-       if (status)
-               ksft_exit_fail_msg("Unable to create a tmpfs for testing\n");
+       if (status) {
+               ksft_print_msg("Unable to create a tmpfs for testing\n");
+               goto out;
+       }
 
        status = snprintf(testfile, INPUT_MAX, "%s/thp_file", tmpfs_loc);
        if (status >= INPUT_MAX) {
@@ -547,10 +552,13 @@ static void split_file_backed_thp(int order)
 
        status = umount(tmpfs_loc);
        if (status) {
-               rmdir(tmpfs_loc);
-               ksft_exit_fail_msg("Unable to umount %s\n", tmpfs_loc);
+               ksft_print_msg("Unable to umount %s\n", tmpfs_loc);
+               goto out;
        }
 
+       free(file_buf1);
+       free(file_buf2);
+
        status = rmdir(tmpfs_loc);
        if (status)
                ksft_exit_fail_msg("cannot remove tmp dir: %s\n", strerror(errno));
@@ -563,8 +571,10 @@ close_file:
        close(fd);
 cleanup:
        umount(tmpfs_loc);
-       rmdir(tmpfs_loc);
 out:
+       free(file_buf1);
+       free(file_buf2);
+       rmdir(tmpfs_loc);
        ksft_exit_fail_msg("Error occurred\n");
 }