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 B445A28A3EE; Thu, 3 Apr 2025 19:10:41 +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=1743707441; cv=none; b=c/qrLspKzy4gYHnRLb2j3+1XI+8l/Hb1g5hGzhCk/9MDbTweMEjUnmNrjnApimOzCJSCmAD24ULJDflwTm9uiuUnA5lFKyOwd9hSF6NUBmxBjlMPXGMWGjbRzqYcQ5ZUXjeh0BdS3yhFqA0tJoT2ZABfN+/xK97IfiC148OS/mI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743707441; c=relaxed/simple; bh=M7lFV45Fx+2+0E22nSVxRdUTHbc4t70UypBkKOnWtR8=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=RmotBm5PBfOQFiCxN8/HiVG2RcOxbzQUC6fp7YOZ91CsWRCSYwg2BMa+iYcsQRLEJ/3qm/vG2yxGUuRh/0Zt0+q0CrGgrG1buWZT8QxEQ6v4u4CVYPdfw/chju7Ro+iAX3noaFxEvlIPajf562xe8LMKwHi1UEKN+jsOMa0RE1Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oJUvs7dS; 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="oJUvs7dS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D507C4CEE3; Thu, 3 Apr 2025 19:10:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1743707441; bh=M7lFV45Fx+2+0E22nSVxRdUTHbc4t70UypBkKOnWtR8=; h=From:To:Cc:Subject:Date:From; b=oJUvs7dSqSiAVgFqnYEKz53/CAUlAWYBlZ5O2P4pELOhef+ShMJo7YkLK0wi/16MH 7YMydJK+UgeIz91ZyMMUnT9y/v4cznf8HD5yYj3ptP6TdXkukeoyTTzp5+zP+ISrrh +75YcF9PXLsb0s86RgNizwTn6E2mH3BVxdPl+5T/GxOtoOwRKGO4KUkiW2kS+pu3Yr zuvnd2ycmueWHMJgLA6U+HIOPaXek42JJ4Pn5Q9c6/xW33V+ck03CgdO6VL4OjIXPN lwtANlRIxSzbIRsk1ckqwuXqtrD3hxp6B/rjQ0waC53Y7XIZ6QyZ3Vp+G625tSbJTq 4QbLtieb4hz7A== 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 5.4 01/14] page_pool: avoid infinite loop to schedule delayed worker Date: Thu, 3 Apr 2025 15:10:23 -0400 Message-Id: <20250403191036.2678799-1-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 5.4.291 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 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