From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B5BB6251780; Tue, 29 Apr 2025 17:41:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745948512; cv=none; b=OCHnx8qPjYEjL4etD+qzfEWbh14WVyIjONJD9tS+wi2irgEoqYK3/I+8bfuYauOpvxOZcWoGipvT5swTNiq8ToCVxoPT7h2nycfFvzBrgVanWbX8e6pex+4pLeBefCiSIyqq2YhkU+WstLQZhkto63BytfKhwK6id08X18kC/rY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745948512; c=relaxed/simple; bh=Uko+R7AvdiQZ6MEHV9YrMyu/ReDeecjypYc9WGXPvcA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=a34sEnIHN1cIbnuIJkH/f45DzPjfOlPp6d0rxl81FTbl79cHJYCX8AsUS6YVMktpqwn9ZVytsnTb0nPErT4Ue8bg4F43FdyekO6mf2ljuiMXgySZVfFGLVOqvKglnGP7Buchn3leDnDK93g9xOsyn8XbrsuM+XFQozMoRAFVzJI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=mmPCxycP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mmPCxycP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 365B5C4CEE9; Tue, 29 Apr 2025 17:41:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745948512; bh=Uko+R7AvdiQZ6MEHV9YrMyu/ReDeecjypYc9WGXPvcA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mmPCxycP1PaUjK0DClobSeOXYaii4HtDvlQEagPuGAOYoyAPt5yIQC0RFk2KyZE/t HFVAO5c0NDfq13h94kdCB36zWxvqiyX7dkD9GOeeD8B8DTGop+aI5WW1UJshW9z61D SdFaRxBoNhIbUVfvJWbb/J4QY+K8nO8/YMRJNXLQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jason Xing , Mina Almasry , Paolo Abeni , Sasha Levin Subject: [PATCH 5.15 023/373] page_pool: avoid infinite loop to schedule delayed worker Date: Tue, 29 Apr 2025 18:38:20 +0200 Message-ID: <20250429161124.085525157@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250429161123.119104857@linuxfoundation.org> References: <20250429161123.119104857@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jason Xing [ Upstream commit 43130d02baa137033c25297aaae95fd0edc41654 ] We noticed the kworker in page_pool_release_retry() was waken up repeatedly and infinitely in production because of the buggy driver causing the inflight less than 0 and warning us in page_pool_inflight()[1]. Since the inflight value goes negative, it means we should not expect the whole page_pool to get back to work normally. This patch mitigates the adverse effect by not rescheduling the kworker when detecting the inflight negative in page_pool_release_retry(). [1] [Mon Feb 10 20:36:11 2025] ------------[ cut here ]------------ [Mon Feb 10 20:36:11 2025] Negative(-51446) inflight packet-pages ... [Mon Feb 10 20:36:11 2025] Call Trace: [Mon Feb 10 20:36:11 2025] page_pool_release_retry+0x23/0x70 [Mon Feb 10 20:36:11 2025] process_one_work+0x1b1/0x370 [Mon Feb 10 20:36:11 2025] worker_thread+0x37/0x3a0 [Mon Feb 10 20:36:11 2025] kthread+0x11a/0x140 [Mon Feb 10 20:36:11 2025] ? process_one_work+0x370/0x370 [Mon Feb 10 20:36:11 2025] ? __kthread_cancel_work+0x40/0x40 [Mon Feb 10 20:36:11 2025] ret_from_fork+0x35/0x40 [Mon Feb 10 20:36:11 2025] ---[ end trace ebffe800f33e7e34 ]--- Note: before this patch, the above calltrace would flood the dmesg due to repeated reschedule of release_dw kworker. Signed-off-by: Jason Xing Reviewed-by: Mina Almasry Link: https://patch.msgid.link/20250214064250.85987-1-kerneljasonxing@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/core/page_pool.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/core/page_pool.c b/net/core/page_pool.c index 069d6ba0e33fb..416be038e1cae 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -699,7 +699,13 @@ static void page_pool_release_retry(struct work_struct *wq) int inflight; inflight = page_pool_release(pool); - if (!inflight) + /* In rare cases, a driver bug may cause inflight to go negative. + * Don't reschedule release if inflight is 0 or negative. + * - If 0, the page_pool has been destroyed + * - if negative, we will never recover + * in both cases no reschedule is necessary. + */ + if (inflight <= 0) return; /* Periodic warning */ -- 2.39.5