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=1793210369; b=B0OO19sV/gHyW0BbKJ7n1VunY6YUIo84jxoCpcGbvQdLsbAcYBKYxS8yoKjZnRFiEEcU 0Z414y0NEvB0O7CPViUOCfxXzD6HzXxANNceEEn8THplqcVPXWx+sBZZhgzv5QuxiEPkn JGFrTlGc/KtOk9DxZVqf87K0nbjsi1VoEpvuUVYj1vks9TN6tnmXX04eX7OlD2f+qPdB9 AW6iTSsE5FkE8VsfDv9QwRsNNUU7HAShH1N9yv+bOOpZR0ZBeOku4Su/e0spzXm6tH9wx icq5GxQE7r8xMkZ8S7vN9ZbiN7AqTv41jCB3SFkD+XenyMo/htPGh+T50pgS+pLBtRA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793210369; 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=J8O7+9R0Jy+tcszSGR/PYqP1LM+7BQDHemdNMN3oFb4=; b=pVqyHYRFSW/E9rIT34jjX0LaAtI0fb5WCgOj8fDO/3U2RxI5+9FgqqiMXkim8YNg+Zj0 DQVqqA8zCBv+SUwgrX2OZB4nxG/MDj54PyHnBYupxlAu8x6RSi3i5t+KWZVPSJq5Frv3g /xbMtieGIcQH6P6jHmKFxxPH1Wgk/+rusZFG8UX/dF7CpPuGt84Ul5Rc2vow8NWw9W5Sp cnh8DWYyFFDMHWwde/h0LXD7ymvlFO9R+1bXYjvYvTDW0bW9XcIU6LzJELIuRsWUKNiqT ASIaYm358e1e28apudyD58ygLNcZI/EdVQDopR7oj68NXTBlylendxdrdiMW80qT+MQ== 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=0DiJpQOQ; 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 558B9606A31E; Wed, 28 Oct 2026 17:59:29 +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=0DiJpQOQ Received: by smtp.kernel.org (Postfix) with ESMTPSA id A64CC1F01825; Wed, 28 Oct 2026 17:59:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793210369; bh=J8O7+9R0Jy+tcszSGR/PYqP1LM+7BQDHemdNMN3oFb4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=0DiJpQOQpShTWN+yBCQ04+9Kj01zVI9ELDRybxUOMrbYQSILj4/HQ1RGXJaBObPNE aEIjT4xywXyycogr2Ynf5TKEfX2dtcJGMNdxLrkaIqlMpWuHFoplxcV6XfxQouLdjB 5CsAbfet7BN5Elrwcb4xE2gUZtTColaEPHDx28PM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jens Axboe Subject: [PATCH 6.6 150/168] io_uring/timeout: dont flush with the sequence behind the last flush Date: Wed, 28 Oct 2026 18:01:26 +0100 Message-ID: <20261028165946.635784578@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165943.089486480@linuxfoundation.org> References: <20261028165943.089486480@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jens Axboe Commit 85f85d573ffa7772e1ad4504d0cec5113a5c5cf1 upstream. io_flush_timeouts() measures the events since the last flush as the distance of the current sequence from ->cq_last_tm_flush. A fired timeout bumps ->cq_timeouts before its CQE is posted, so until it is the sequence can be behind the last flush, and the distance wraps: last flush: seq 100, cq_last_tm_flush = 100 Y: IORING_OP_TIMEOUT, off 50, target_seq 150 pure timeout A fires, cq_timeouts = 1 task_work posts A's CQE, cached_cq_tail = 101 pure timeout B fires before the flush, cq_timeouts = 2 io_flush_timeouts(): seq = 99, events_got = 0xffffffff Y, and every sequence timeout behind it, is ended with -ETIME although no event happened. Two timeouts expiring close together is all it takes, a completion with IOSQE_CQE_SKIP_SUCCESS after a single one does it too. Nothing but those in flight CQEs separates the two, so count from the last flush when the sequence is behind it, as io_timeout() does. Fixes: f010505b78a4 ("io_uring: flush timeouts that should already have expired") Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- io_uring/timeout.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/io_uring/timeout.c +++ b/io_uring/timeout.c @@ -116,6 +116,14 @@ __cold void io_flush_timeouts(struct io_ spin_lock_irq(&ctx->timeout_lock); seq = ctx->cached_cq_tail - atomic_read(&ctx->cq_timeouts); + /* + * A fired timeout bumps ->cq_timeouts before its CQE is posted, which + * leaves the sequence behind the last flush until it is. No event has + * happened then, see io_timeout(). + */ + if ((s32)(seq - ctx->cq_last_tm_flush) < 0) + seq = ctx->cq_last_tm_flush; + list_for_each_entry_safe(timeout, tmp, &ctx->timeout_list, list) { struct io_kiocb *req = cmd_to_io_kiocb(timeout); u32 events_needed, events_got;