stable.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Florian Faber <faber@faberman.de>,
	Marc Kleine-Budde <mkl@pengutronix.de>
Subject: [PATCH 4.4 13/28] can: mscan: mscan_rx_poll(): fix rx path lockup when returning from polling to irq mode
Date: Tue, 14 Jan 2020 11:02:15 +0100	[thread overview]
Message-ID: <20200114094342.088889078@linuxfoundation.org> (raw)
In-Reply-To: <20200114094336.845958665@linuxfoundation.org>

From: Florian Faber <faber@faberman.de>

commit 2d77bd61a2927be8f4e00d9478fe6996c47e8d45 upstream.

Under load, the RX side of the mscan driver can get stuck while TX still
works. Restarting the interface locks up the system. This behaviour
could be reproduced reliably on a MPC5121e based system.

The patch fixes the return value of the NAPI polling function (should be
the number of processed packets, not constant 1) and the condition under
which IRQs are enabled again after polling is finished.

With this patch, no more lockups were observed over a test period of ten
days.

Fixes: afa17a500a36 ("net/can: add driver for mscan family & mpc52xx_mscan")
Signed-off-by: Florian Faber <faber@faberman.de>
Cc: linux-stable <stable@vger.kernel.org>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/can/mscan/mscan.c |   21 ++++++++++-----------
 1 file changed, 10 insertions(+), 11 deletions(-)

--- a/drivers/net/can/mscan/mscan.c
+++ b/drivers/net/can/mscan/mscan.c
@@ -392,13 +392,12 @@ static int mscan_rx_poll(struct napi_str
 	struct net_device *dev = napi->dev;
 	struct mscan_regs __iomem *regs = priv->reg_base;
 	struct net_device_stats *stats = &dev->stats;
-	int npackets = 0;
-	int ret = 1;
+	int work_done = 0;
 	struct sk_buff *skb;
 	struct can_frame *frame;
 	u8 canrflg;
 
-	while (npackets < quota) {
+	while (work_done < quota) {
 		canrflg = in_8(&regs->canrflg);
 		if (!(canrflg & (MSCAN_RXF | MSCAN_ERR_IF)))
 			break;
@@ -419,18 +418,18 @@ static int mscan_rx_poll(struct napi_str
 
 		stats->rx_packets++;
 		stats->rx_bytes += frame->can_dlc;
-		npackets++;
+		work_done++;
 		netif_receive_skb(skb);
 	}
 
-	if (!(in_8(&regs->canrflg) & (MSCAN_RXF | MSCAN_ERR_IF))) {
-		napi_complete(&priv->napi);
-		clear_bit(F_RX_PROGRESS, &priv->flags);
-		if (priv->can.state < CAN_STATE_BUS_OFF)
-			out_8(&regs->canrier, priv->shadow_canrier);
-		ret = 0;
+	if (work_done < quota) {
+		if (likely(napi_complete_done(&priv->napi, work_done))) {
+			clear_bit(F_RX_PROGRESS, &priv->flags);
+			if (priv->can.state < CAN_STATE_BUS_OFF)
+				out_8(&regs->canrier, priv->shadow_canrier);
+		}
 	}
-	return ret;
+	return work_done;
 }
 
 static irqreturn_t mscan_isr(int irq, void *dev_id)



  parent reply	other threads:[~2020-01-14 10:13 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-14 10:02 [PATCH 4.4 00/28] 4.4.210-stable review Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 01/28] kobject: Export kobject_get_unless_zero() Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 02/28] chardev: Avoid potential use-after-free in chrdev_open() Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 03/28] usb: chipidea: host: Disable port power only if previously enabled Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 04/28] ALSA: usb-audio: Apply the sample rate quirk for Bose Companion 5 Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 05/28] kernel/trace: Fix do not unregister tracepoints when register sched_migrate_task fail Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 06/28] tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not defined Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 07/28] HID: Fix slab-out-of-bounds read in hid_field_extract Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 08/28] HID: uhid: Fix returning EPOLLOUT from uhid_char_poll Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 09/28] HID: hid-input: clear unmapped usages Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 10/28] Input: add safety guards to input_set_keycode() Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 11/28] drm/dp_mst: correct the shifting in DP_REMOTE_I2C_READ Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 12/28] can: gs_usb: gs_usb_probe(): use descriptors of current altsetting Greg Kroah-Hartman
2020-01-14 10:02 ` Greg Kroah-Hartman [this message]
2020-01-14 10:02 ` [PATCH 4.4 14/28] can: can_dropped_invalid_skb(): ensure an initialized headroom in outgoing CAN sk_buffs Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 15/28] staging: vt6656: set usb_set_intfdata on driver fail Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 16/28] USB: serial: option: add ZLP support for 0x1bc7/0x9010 Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 17/28] usb: musb: Disable pullup at init Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 18/28] usb: musb: dma: Correct parameter passed to IRQ handler Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 19/28] staging: rtl8188eu: Add device code for TP-Link TL-WN727N v5.21 Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 20/28] tty: link tty and port before configuring it as console Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 21/28] tty: always relink the port Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 22/28] mwifiex: fix possible heap overflow in mwifiex_process_country_ie() Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 23/28] mwifiex: pcie: Fix memory leak in mwifiex_pcie_alloc_cmdrsp_buf Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 24/28] scsi: bfa: release allocated memory in case of error Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 25/28] rtl8xxxu: prevent leaking urb Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 26/28] USB: Fix: Dont skip endpoint descriptors with maxpacket=0 Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 27/28] netfilter: arp_tables: init netns pointer in xt_tgchk_param struct Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.4 28/28] netfilter: ipset: avoid null deref when IPSET_ATTR_LINENO is present Greg Kroah-Hartman
2020-01-14 15:01 ` [PATCH 4.4 00/28] 4.4.210-stable review Jon Hunter
2020-01-14 18:14 ` Guenter Roeck
2020-01-14 23:29 ` shuah
2020-01-15  2:08 ` Daniel Díaz

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200114094342.088889078@linuxfoundation.org \
    --to=gregkh@linuxfoundation.org \
    --cc=faber@faberman.de \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mkl@pengutronix.de \
    --cc=stable@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).