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 2ABA825A2D9; Thu, 3 Apr 2025 19:09:30 +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=1743707370; cv=none; b=JfRBSosq/iX6waZ30Sfbs158EEQJJmvCjqvPmCpHBL5nU9G2vS+YO1A2zasJgx5p0yvck8RIfQ2OHqMt0F6VwS9Wc5nKjI+lhF9BFJvrlZRGQ4eqAkmeoGjbuBVcgnAWnWE8xyBA2YAwwW9n4hvMVFm0CHtu/k1IfePz3ahmnqw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743707370; c=relaxed/simple; bh=6csg7lD3PhrFQZR4E3Q4CG4jjknvEMYAhVJ00Ba8LBo=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=XzLS3+B0rHyaCwpoEx5M4jhf1Ni0IVRyWUnEpaDSTS1pE1mJTDb8WQXWhh7hM12GDOKDQo9qx+XCZ2pcRffZJQRKMrpsTA0gIr3nX8hZSCFqZ2zrPIEOXL4mupaWIrRArpUkbG2FwL+DxD4zFGXK3I9NdF4/N++j1nVi0aT41gg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=FZtW8Gwi; 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="FZtW8Gwi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B058BC4CEE3; Thu, 3 Apr 2025 19:09:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743707370; bh=6csg7lD3PhrFQZR4E3Q4CG4jjknvEMYAhVJ00Ba8LBo=; h=From:To:Cc:Subject:Date:From; b=FZtW8GwirKqS86JYgVFQis182VFbqkj2Z+pKGnifNacE63upjFBU8R2CDfqRtQFWL 81wFE77greGthfF4ybRnpVM+0TptewEkb7BzxqyrMQZ7XTmckRtAkdsJrxQ7/fhRZD uLBPPGi6KPfm4aVHOceTZ41Ukn0rgkS3kJoJW5n7n6z0DOD2XC1O5HdWmcLQ9azo5o PBGskfBu3Iz8Faf8DWXJeYwXJgNrOikl1jvpFwFavF+5TlbAwZ9tlwh7ltQ5a5qHVV +fNDp4nkm0tXRHmx9S/ZI80snJeBeUrhBfQxCPFdaeDUm/nv6G/uUITsNWxj0p/O9n eH5udkY9+cGXQ== 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 5.15 01/16] page_pool: avoid infinite loop to schedule delayed worker Date: Thu, 3 Apr 2025 15:09:09 -0400 Message-Id: <20250403190924.2678291-1-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 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 5.15.179 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 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