From 93d93f5f8da791e98159795c6ef683f45bd95d13 Mon Sep 17 00:00:00 2001 From: Heechan Kang Date: Sun, 17 May 2026 03:47:09 +0900 Subject: [PATCH] io_uring/waitid: clear waitid info before copying it to userspace IORING_OP_WAITID stores its result fields in struct io_waitid::info and later copies them to userspace siginfo. The prep path initializes the request arguments, but it does not initialize info itself. If the wait operation completes without reporting a child event, the common wait code can return without writing wo_info. In that case io_waitid_finish() still copies iw->info to userspace, exposing stale bytes from the reused io_kiocb command storage. Clear the result storage during prep so the io_uring path matches the regular waitid syscall, which uses a zero-initialized struct waitid_info. Fixes: f31ecf671ddc ("io_uring: add IORING_OP_WAITID support") Cc: stable@vger.kernel.org # 6.7+ Signed-off-by: Heechan Kang Link: https://patch.msgid.link/20260516184709.852814-1-gganji11@naver.com Signed-off-by: Jens Axboe --- io_uring/waitid.c | 1 + 1 file changed, 1 insertion(+) diff --git a/io_uring/waitid.c b/io_uring/waitid.c index d25d60aed6af..32f68fd7fcdd 100644 --- a/io_uring/waitid.c +++ b/io_uring/waitid.c @@ -275,6 +275,7 @@ int io_waitid_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) iw->options = READ_ONCE(sqe->file_index); iw->head = NULL; iw->infop = u64_to_user_ptr(READ_ONCE(sqe->addr2)); + memset(&iw->info, 0, sizeof(iw->info)); return 0; }