From e5d3e1422e92d54e28e81fad8bfc7c1ecb41a353 Mon Sep 17 00:00:00 2001 From: Sayali Patil Date: Thu, 21 May 2026 12:17:47 +0530 Subject: [PATCH] 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 Reviewed-by: Zi Yan Tested-by: Venkat Rao Bagalkote Cc: David Hildenbrand (Arm) Cc: Dev Jain Cc: Liam Howlett Cc: Miaohe Lin Cc: Michal Hocko Cc: Oscar Salvador Cc: "Ritesh Harjani (IBM)" Cc: Shuah Khan Signed-off-by: Andrew Morton --- .../selftests/mm/split_huge_page_test.c | 22 ++++++++++++++----- 1 file changed, 16 insertions(+), 6 deletions(-) diff --git a/tools/testing/selftests/mm/split_huge_page_test.c b/tools/testing/selftests/mm/split_huge_page_test.c index 9a50557069ad..32b991472f74 100644 --- 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 @@ static void split_file_backed_thp(int order) 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"); }