From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from vps0.lunn.ch (vps0.lunn.ch [156.67.10.101]) (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 90D8430E84F; Mon, 30 Mar 2026 12:46:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=156.67.10.101 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774874793; cv=none; b=nkbMx6zfqY3BqNu7QgoYxSgzRaSzg3K98OLfjLe2D7dCzFsmXP/2EYit6sy+iM1sUJMDluzXpsCsi/tmxOshHoG7zJz6VEdbOYbCqAHjliEncii/y86ryAi1HSkx0zbQ7HWX5HpEXeniTcF34l6NpzVXn9k0KXILBtY+o1gxppE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774874793; c=relaxed/simple; bh=+JI1lyVpwmCdQmV9IzVwmr2ini/KIrHwAFCVRT27qCY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=L5EYa4msTpfHbCDDx9FBdcxaP1O9zYvfCPwpPRE3RnDUjL+XO95k+uR45Jh/9A76enknBLjpFXlSJOnOFiVfVroOPUniBCHll5TndnvbgpX6uwY42Y8JWiK0nqHotnoMJqcHDLpA8zFQEl2iwp2dUjGoPDEblizaL98DQl0DYoI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch; spf=pass smtp.mailfrom=lunn.ch; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b=UQb9qx6x; arc=none smtp.client-ip=156.67.10.101 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lunn.ch Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="UQb9qx6x" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=X22xCMJmu+cCZa6SjDViytKlQGgWoaHzcMM/4kRa0lY=; b=UQb9qx6x0SumTYNtBWwA3KVjak SJbzjiC7revnqpS7MiEnD7lPS11/w0KZnO9LKnxQrXtU7xGOlXHuMk5qmjxMMyk7SoVr9JOP+yQ3S ipZziRwBNBl0+CCrMtZepHXdUfRQ3VRCtbECSYt6wE/j5ZPEfOjy0i6JrsDEYNS3aR8s=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1w7C0e-00E22J-42; Mon, 30 Mar 2026 14:46:24 +0200 Date: Mon, 30 Mar 2026 14:46:24 +0200 From: Andrew Lunn To: "Maciej W. Rozycki" Cc: Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next] FDDI: defxx: Rate-limit memory allocation errors Message-ID: <6f38637b-87bb-48ad-a6f9-8eec5f33ec93@lunn.ch> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Sun, Mar 29, 2026 at 01:32:25PM +0100, Maciej W. Rozycki wrote: > Prevent the system from becoming unstable or unusable due to a flood of > memory allocation error messages under memory pressure, e.g.: > > [...] > fddi0: Could not allocate receive buffer. Dropping packet. > fddi0: Could not allocate receive buffer. Dropping packet. > fddi0: Could not allocate receive buffer. Dropping packet. > fddi0: Could not allocate receive buffer. Dropping packet. > rcu: INFO: rcu_sched self-detected stall on CPU > rcu: 0-...!: (332 ticks this GP) idle=255c/1/0x40000000 softirq=16420123/16420123 fqs=0 > rcu: (t=2103 jiffies g=35680089 q=4 ncpus=1) > rcu: rcu_sched kthread timer wakeup didn't happen for 2102 jiffies! g35680089 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 > rcu: Possible timer handling issue on cpu=0 timer-softirq=12779658 > rcu: rcu_sched kthread starved for 2103 jiffies! g35680089 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->cpu=0 > rcu: Unless rcu_sched kthread gets sufficient CPU time, OOM is now expected behavior. > rcu: RCU grace-period kthread stack dump: > task:rcu_sched state:I stack:0 pid:14 tgid:14 ppid:2 flags:0x00004000 > Call Trace: > __schedule+0x258/0x580 > schedule+0x19/0xa0 > schedule_timeout+0x4a/0xb0 > ? hrtimers_cpu_dying+0x1b0/0x1b0 > rcu_gp_fqs_loop+0xb1/0x450 > rcu_gp_kthread+0x9d/0x130 > kthread+0xb2/0xe0 > ? rcu_gp_init+0x4a0/0x4a0 > ? kthread_park+0x90/0x90 > ret_from_fork+0x2d/0x50 > ? kthread_park+0x90/0x90 > ret_from_fork_asm+0x12/0x20 > entry_INT80_32+0x10d/0x10d > CPU: 0 UID: 500 PID: 21895 Comm: 31370.exe Not tainted 6.13.0-dirty #2 > > (here running the libstdc++-v3 testsuite). > > Signed-off-by: Maciej W. Rozycki Reviewed-by: Andrew Lunn Andrew