On Fri, 15 May 2026 09:22:11 +0000 Wei Yang <[email protected]> wrote:
> On Tue, May 12, 2026 at 01:19:24PM +0530, Vineet Agarwal wrote: > >create_pagecache_thp_and_fd() fills the backing file for the > >pagecache THP tests using repeated write() calls, but the return > >value is never checked. > > > >If a write fails or completes only partially, the test may continue > >with an incompletely initialized file and produce misleading results. > > > >Check the result of write() and fail the test if the expected number > >of bytes was not written. > > > >Signed-off-by: Vineet Agarwal <[email protected]> > >--- > > tools/testing/selftests/mm/split_huge_page_test.c | 13 ++++++++++--- > > 1 file changed, 10 insertions(+), 3 deletions(-) > > > >diff --git a/tools/testing/selftests/mm/split_huge_page_test.c > >b/tools/testing/selftests/mm/split_huge_page_test.c > >index 500d07c4938b..eab69b0f59a0 100644 > >--- a/tools/testing/selftests/mm/split_huge_page_test.c > >+++ b/tools/testing/selftests/mm/split_huge_page_test.c > >@@ -609,9 +609,16 @@ static int create_pagecache_thp_and_fd(const char > >*testfile, size_t fd_size, > > assert(fd_size % sizeof(buf) == 0); > > for (i = 0; i < sizeof(buf); i++) > > buf[i] = (unsigned char)i; > >- for (i = 0; i < fd_size; i += sizeof(buf)) > >- write(*fd, buf, sizeof(buf)); > >- > >+ for (i = 0; i < fd_size; i += sizeof(buf)) { > >+ ssize_t written; > >+ > >+ written = write(*fd, buf, sizeof(buf)); > >+ if (written != sizeof(buf)) { > >+ ksft_perror("write testfile"); > >+ close(*fd); > >+ goto err_out_unlink; > > Maybe we can "goto err_out_close" and remove the close() here? AI review suggested the same: https://sashiko.dev/#/patchset/20260512074924.27721-1-agarwal.vineet2006%40gmail.com And it complained about the handling of short writes in the added code. > Apart from this, I found on error writing to /proc/sys/vm/drop_caches in > below, > it just goto err_out_unlink, which left fd open. Not understanding - cab you please describe more completely? > How about fix that at the same time. > > Generally, the change look good. >
