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Sat, 16 May 2026 11:28:03 -0700 (PDT) Received: from [192.168.1.150] ([198.8.77.157]) by smtp.gmail.com with ESMTPSA id 586e51a60fabf-439fc53f2acsm7139967fac.14.2026.05.16.11.28.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 16 May 2026 11:28:03 -0700 (PDT) Message-ID: <6a23b132-35bd-425a-b957-c63dc5cbba49@kernel.dk> Date: Sat, 16 May 2026 12:28:02 -0600 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] io_uring/waitid: clear waitid info before copying it to userspace To: =?UTF-8?B?6rCV7Z2s7LCs?= , io-uring@vger.kernel.org Cc: linux-kernel@vger.kernel.org References: <656b27a69e38857237c82fe0c5d11fba@cweb018.nm> Content-Language: en-US From: Jens Axboe In-Reply-To: <656b27a69e38857237c82fe0c5d11fba@cweb018.nm> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 5/16/26 12:24 PM, 강희찬 wrote: > > 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 > --- >  io_uring/waitid.c | 1 + >  1 file changed, 1 insertion(+) > > diff --git a/io_uring/waitid.c b/io_uring/waitid.c > index d25d60aed6a..32f68fd7fcd 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; >  } Patch looks fine, but you can't send html formatted stuff - it won't make it to the list, and it also corrupts the patch so it can't get applied. Send everything plain/text. -- Jens Axboe