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=1793209811; b=VwAE2MrLuyfCHy/HOSqLQJLTFZXK9w5AypiLqgiSBjjm3iKk8gsLw5OjgZge1fZ0pNU4 i5banATkLltWVJtuej+JhpkyhtUhdS7fJmFbrIxKs3U1RGZwyW++o4dUbJZZpKj989CG5 VD/kUbP778RMLHqln+1VeW1V4P2GP3nuT6GKHbq1H1L6tMQkNvIzS7vZLyN1I+fyy7Ce7 cycfMRyXtjtyeCmIcHvSbMIgEyemvurUvPck+nv9RydfxLpG+vgMh92geduH8qPFzKPyW 27Te21NQzUtYgibIM5IPXyjuoWHWsOR8cHkr6F5/s67yQepVdWsP4q0KPaL7Kad54fQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793209811; 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=/gDftI/4NaAnL1lwLXNLj4zsGZXkQhwMloHX2aJI7AM=; b=jLlQ9o2djV0aF3X3isI45euL/IDifAEJuIKSTwVowXYKlNHjRiibPnRJNzxuZvSaEjKe OuKGvYi9NXLNEzgtKSPMtQLTQbN0yyXQ9VbG2epB4kETp4wMS9Z7jLs5wGpg9VdU5GImB xR631ArdV0fJSFH4/ZSCUDhoNmTwbHeVZGmCA50tJ2rKee/NqVr6mC8NJJl5OndLZWAZP Ld6sjZGgEaEEqL1KlkxbZFMe0N85nWgQRk5RXbAB8GB/E9Tl9bzz2yzK1KWQxTnD+zW3q uM6krL64iOYxOgkP+1YDCOmdDEB1TgVP0frhHGFBbqQUuZFn2x2DuSlrrhomdXfa+zA== 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=g3UE8aTu; 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 227AA606A31A; Wed, 28 Oct 2026 17:50:11 +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=g3UE8aTu Received: by smtp.kernel.org (Postfix) with ESMTPSA id 717F71F01825; Wed, 28 Oct 2026 17:50:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793209811; bh=/gDftI/4NaAnL1lwLXNLj4zsGZXkQhwMloHX2aJI7AM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=g3UE8aTuT/vgKHYodgNiJNn+yWQvWyQ0/el3RgT2RKD/dIu1D3o/kUWshB9OnLEPT cNW0TbdWz0jWdAwks6/9vxsqQEjpK/3SDI9lnudp2rzLIAYxoWYslNxtp5JiiYl0em lJNEY1C04aybbzmzOYOP8qgSK6SOxhvy+dtHrKMY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jens Axboe Subject: [PATCH 6.18 083/109] io_uring/timeout: dont flush with the sequence behind the last flush Date: Wed, 28 Oct 2026 18:01:07 +0100 Message-ID: <20261028165944.311883630@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165942.357251485@linuxfoundation.org> References: <20261028165942.357251485@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 6.18-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 @@ -132,6 +132,14 @@ __cold void io_flush_timeouts(struct io_ raw_spin_lock_irq(&ctx->timeout_lock); seq = READ_ONCE(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;