From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793207989; b=0PYQdxsLJl4uoOXt/iU6A6FrgYm6ON5emmyk2x84NbdE3mdKlDWC6r6YibHSjV8J+hOG hWqTVFMipIqn19GSIXiegbT/gl7MT0VfHhCgWLqbNWWSZqmJSZENI3Q86QUD67vJS5Kk+ ZNxh8etAXIII9qNeKkLVlNbveXj0UzlXBxY7jt/A0JU6UguVIpJesa9k/TFw0ehMYH6wX azUi9kVwdTChLgKdeLNJ5zra6TjezmpYBpdkdqYmRHgZtODG06Y3vHSQ8T0qkrQNq6G3W YZ53jVQt1zZZang/CypaA4ptIwwijos2Ua/ryruLDXLcXVynAKgjhzgIVVn5i56ljOA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793207989; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=M3gTFUuZW5E56UH53pWWPyROQQnnKCB5FV9hS8TasPw=; b=gwE2l13X0wDeEKx3hilt/5sSyu9TbUpQwUTFz2pbWP595sKubVAGgSgeDV3VMDV54BGd oUUTb3+4geHLuLxYMs6IA6jPSQmcl5I19KylCrBASvcifGmWeCT6U3owqIH0Uq6c4e1aG 1nbGtBwTSLCzI3NSzhJ6GHpwJcgVI753SERRM1hE6kFeJXx8jOTZPlHzxY6b4RLdLwkn8 +sw2IqaezOCToSbYIUA7b9iNm4sWCD94taIyKzmQwyVtxvAQAHf7YXMpFTLVwY5i3ZaIk XmdzNeST6K7MCUYIHJzkdA+vWFLYPrtGUFj8AooOPCpmr1UgQ8z5cxoCY03MIa+izSA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="zlrpTS/V"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3BBD9606A31A; Wed, 28 Oct 2026 17:19:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=zlrpTS/V Received: by smtp.kernel.org (Postfix) with ESMTPSA id 89CD91F031E5; Wed, 28 Oct 2026 17:19:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793207989; bh=M3gTFUuZW5E56UH53pWWPyROQQnnKCB5FV9hS8TasPw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=zlrpTS/VgPyB2k1QruKxyzRe/n6aEwFaCVwKlC4DagJKEYuH9c/9lj/pfzG8Laepz ByqsksLjFdeDktS7nKj1GMJuc1+IhloQRzZ7jgLJxWhja5XwXhU1MH+q2vugBA1BtA u4ct9vjL8eKxsqFETJSfrZkY2kwX5nTSHaWkhvlw= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Josef Bacik , Jens Axboe , "Claude Fable 5.1" Subject: [PATCH 6.12 209/247] io_uring/poll: drop stale double poll entry on rearm Date: Wed, 28 Oct 2026 18:00:12 +0100 Message-ID: <20261028165952.369808767@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165947.349197979@linuxfoundation.org> References: <20261028165947.349197979@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josef Bacik Commit f2dbe87968a3aef74a11c025776d293b80964d3f upstream. A file that uses two wait queues for poll, e.g. a tty, gets a second io_poll entry, which IORING_OP_POLL_ADD keeps in ->async_data until the request is freed. io_poll_add() can run more than once for a request though: IORING_OP_POLL_REMOVE with one of the update flags disarms and rearms it, and io_poll_task_func() reissues it if a wake up turns out to be spurious. The second poll_wait() of the new round then finds *poll_ptr set, with ->head cleared by the disarm, and __io_queue_proc() fails what it takes for a third wait queue with -EINVAL. For an update that means that the poll request is completed with -ECANCELED, while the update itself reports success. For a spurious wake up, e.g. tcsetattr() on the polled tty, the poll request fails with -EINVAL. Free the old entry and clear the poll flags before arming, which is what io_arm_apoll() does for internal polling. All entries have been removed from their wait queues at that point. [ 6.12: no io_req_async_data_free(), open-coded ] Fixes: b69de288e913 ("io_uring: allow events and user_data update of running poll requests") Fixes: 6e5aedb9324a ("io_uring/poll: attempt request issue after racy poll wakeup") Assisted-by: LLM Signed-off-by: Josef Bacik Link: https://patch.msgid.link/20261015-b4-io-uring-fixes-v1-21-c1556f5d7bf5@toxicpanda.com Signed-off-by: Jens Axboe Co-Authored-By: Claude Fable 5.1 Signed-off-by: Greg Kroah-Hartman --- io_uring/poll.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -996,6 +996,18 @@ int io_poll_add(struct io_kiocb *req, un if (req->ctx->flags & (IORING_SETUP_SQPOLL|IORING_SETUP_SINGLE_ISSUER)) req->flags |= REQ_F_HASH_LOCKED; + /* + * A poll update or a spurious wake up arms the request again. Forget + * the entries of the previous round like io_arm_apoll() does, a stale + * second entry would be taken for a third wait queue. + */ + if (req_has_async_data(req)) { + kfree(req->async_data); + req->async_data = NULL; + req->flags &= ~REQ_F_ASYNC_DATA; + } + req->flags &= ~(REQ_F_SINGLE_POLL | REQ_F_DOUBLE_POLL); + ret = __io_arm_poll_handler(req, poll, &ipt, poll->events, issue_flags); if (ret > 0) { io_req_set_res(req, ipt.result_mask, 0);