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 BE1FB258CC4; Thu, 3 Apr 2025 19:07:58 +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=1743707278; cv=none; b=gj8CPv8c++Wo0eUz2c460Ib1zVpmgnMZOdZ6fGsg5A44k43CpXnBxpTIO2XRxKjF9gYHP1gq7AGX1YR0Ls9atSXEc+rOxqBxhuPQ64p70D+R25SUkMPFvkQuT6SVEujaK7HMQigsQ3J7Lxcfo0O90U5yjEIB3Z1WC0RtffLj5Rk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743707278; c=relaxed/simple; bh=K2We6ttfT2NRzab29J4tAo+tCc735Er7VDiK3//0el4=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=QWYsRrdmMLuJ7cYc6sibFL/kMD38drXskEs+VVNMH3gvfnFMh8PPlq8e4srE5o9yGo6z6tCNk6W/Cf6ZjRvCIdfOTuwCAM/wJ4iuhDmV5dIiapXD9szgaHQz/0IDsvXIKolnY8ZJxKjkFQzPlm3yYEf6TDoQr9dtmXjcmItdJ6s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BKPc2rI9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BKPc2rI9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4AEABC4CEE3; Thu, 3 Apr 2025 19:07:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743707278; bh=K2We6ttfT2NRzab29J4tAo+tCc735Er7VDiK3//0el4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BKPc2rI9lmMxUzm49bmV8Vi0dUGHdhJ26w+3VqOPfvBsqh3A+YFKP88oKQ8uIt9rZ TF4qnQVtGuIKYnK3tYutqB16SrTz2GyZ7X0GAwK1z3iBJfStSPhG7DdH44kKgHVz2f Xhdkhean4fjRFBNRrxfQJplOckh0fUyZd+cmc/USCmKsS6O6bd/Vke4IXgyV17f7u7 IDxcGNLLy2NXZMkZt/IAENrvFh2RTMiVLJgSf4UFafCIv/P6lCxbmXV2fo0KP+2TVE UzSmG+CoBztFL+MJ3GoDrcLi1Cr0l4ThEeTOPQJP0OR2ifAh/zkW6UowPo+3yJ0z4y 1yZ7U+sS8KlDg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Jason Xing , Mina Almasry , Paolo Abeni , Sasha Levin , hawk@kernel.org, ilias.apalodimas@linaro.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, netdev@vger.kernel.org Subject: [PATCH AUTOSEL 6.6 05/26] page_pool: avoid infinite loop to schedule delayed worker Date: Thu, 3 Apr 2025 15:07:24 -0400 Message-Id: <20250403190745.2677620-5-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250403190745.2677620-1-sashal@kernel.org> References: <20250403190745.2677620-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.6.85 Content-Transfer-Encoding: 8bit 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 31f923e7b5c40..2f2f63c8cf4b0 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -865,7 +865,13 @@ 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