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 C1E8B256C91; Thu, 3 Apr 2025 19:02:46 +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=1743706966; cv=none; b=j5jq0L0lNfDTaKXyUFq/cKe3lZrAklnbbRxOu6VngqH2L4t1ZQcB9OniFJ0RdtYZE8AM5ZfZj9xs20lVsc+pd/jwSbx+5wV3s97QU0ZGCJJE9ngiQ7nWpL2dUXIazWosJJoKJXgkPT/OAQtU1zENUe/Hdpcap4+8xFAFa3trTOk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743706966; c=relaxed/simple; bh=7rE74X9+EgHYZG/1kugO9vNjExrNuzVoYCMDI0L4qbw=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=RzJUhsjdFNLgtOPCyVlNPVbhIgZS1YHB5TBLcxoYqqruia/UJVH8yeagwLu+yGitd/iDBGtYqQnaIKi3tJ5lY76IZgh2rUyq+MyjY9XhVgKrijBrYgsYFQQm0OkZUI9D5yh3lnyf8ZK9FAnx5kt2nZ+zDw45jecEMDEBJ1vPG8g= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=r5GgQeXk; 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="r5GgQeXk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA0DDC4CEE9; Thu, 3 Apr 2025 19:02:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743706966; bh=7rE74X9+EgHYZG/1kugO9vNjExrNuzVoYCMDI0L4qbw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=r5GgQeXk7PDiARKvqRhRnc3vbu6HAPDkwcO6qqXn0m8Npi9j4ju5P9h3K8xcTF9RU ep+rrk6c2wBadh8G2qBOuH2UAX2Rg3eGhjFJwDnYSJjnmn2sGd0CFb8+LKJC/b08oc zlRgS3U7TYfvC3nx0FPCfNdgtvOhieYkBbN2hXQrNgbyxBooTb6wWqbbt92Nj0jvaA 5ikdocT99fbTEdFRvDpFYCYGOKJx1S9h4nl4CzNTj6vFK/54GA/z4cBBgTmosQU8Tr IyXySnL80wbcZNRD6xwPCgySku35x1OThRkYL/UliMpUsIsRTf7gLDbLkXuI++Y82n +TppmcdKHO9uw== 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 6.14 16/54] page_pool: avoid infinite loop to schedule delayed worker Date: Thu, 3 Apr 2025 15:01:31 -0400 Message-Id: <20250403190209.2675485-16-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250403190209.2675485-1-sashal@kernel.org> References: <20250403190209.2675485-1-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 6.14 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 f5e908c9e7ad8..ede82c610936e 100644 --- a/net/core/page_pool.c +++ b/net/core/page_pool.c @@ -1104,7 +1104,13 @@ 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 for page pools the user can't see */ -- 2.39.5