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 90B16244668; Tue, 29 Apr 2025 16:45:43 +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=1745945143; cv=none; b=H2zgEU9WTn+PYSXxHscT5ztXG9YVoqWPG/BJAeNCGejghJ3R/J+Ft5Japki1lNb0j0m2hXdkTmBlxoVS6QHrBd1aUY4yptyPuNEQ1yyeJlDpmnhJc8sbe/jANjFWVcmJVsjrvHex74w8gq3wcSLSEpFI3zE5ua0brz5DqAT8smI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745945143; c=relaxed/simple; bh=R6yIhyZBR+aNznR4+fWgHZ9jn/PK06myxcxcgmwTNZU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Yo5Mp8wxaDz9+f5+GU0IfiFBkrnmK3gC7gxudNsUYXDtJxUIM84g+VMdUewZkpxoVE1Nz92b2JAsG7FY3beE8s8iDUIjP5JeXBgv1Kmp78Wgv31Ri/G1YvOO+cMdKGw6JdbrBQKg1jfTJaPFuwMRc8pHk9vqlmbafkLIoQwR47I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=AgAJvSvK; 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="AgAJvSvK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A875EC4CEE3; Tue, 29 Apr 2025 16:45:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745945143; bh=R6yIhyZBR+aNznR4+fWgHZ9jn/PK06myxcxcgmwTNZU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=AgAJvSvKZP1OT5adioLED3zf5rjGX6KDN6FhZtzuJEsLMsENxEWSWZnKHGE87Ewbt MIxV5DT3FIz3KM9aNd7fPY7T/VD54Bld1XLAdQqGf7SjzF8h+6djYeQSE7fDcpMVPt bx6h3OUFrHbx3d5H0GlNmjuA+3QxbFuWzmQa4fzs= 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 5.4 016/179] page_pool: avoid infinite loop to schedule delayed worker Date: Tue, 29 Apr 2025 18:39:17 +0200 Message-ID: <20250429161050.066904931@linuxfoundation.org> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20250429161049.383278312@linuxfoundation.org> References: <20250429161049.383278312@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-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 335f68eaaa05c..dbe0489e46035 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -387,7 +387,13 @@ 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