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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 4.14 11/39] can: mscan: mscan_rx_poll(): fix rx path lockup when returning from polling to irq mode
Date: Tue, 14 Jan 2020 11:01:45 +0100
Message-ID: <20200114094341.641803479@linuxfoundation.org> (raw)
In-Reply-To: <20200114094336.210038037@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 index

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-14 10:01 [PATCH 4.14 00/39] 4.14.165-stable review Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 01/39] chardev: Avoid potential use-after-free in chrdev_open() Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 02/39] usb: chipidea: host: Disable port power only if previously enabled Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 03/39] ALSA: usb-audio: Apply the sample rate quirk for Bose Companion 5 Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 04/39] ALSA: hda/realtek - Add new codec supported for ALCS1200A Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 05/39] ALSA: hda/realtek - Set EAPD control to default for ALC222 Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 06/39] kernel/trace: Fix do not unregister tracepoints when register sched_migrate_task fail Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 07/39] tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not defined Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 08/39] HID: Fix slab-out-of-bounds read in hid_field_extract Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 09/39] HID: uhid: Fix returning EPOLLOUT from uhid_char_poll Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 10/39] can: gs_usb: gs_usb_probe(): use descriptors of current altsetting Greg Kroah-Hartman
2020-01-14 10:01 ` Greg Kroah-Hartman [this message]
2020-01-14 10:01 ` [PATCH 4.14 12/39] can: can_dropped_invalid_skb(): ensure an initialized headroom in outgoing CAN sk_buffs Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 13/39] gpiolib: acpi: Turn dmi_system_id table into a generic quirk table Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 14/39] gpiolib: acpi: Add honor_wakeup module-option + quirk mechanism Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 15/39] staging: vt6656: set usb_set_intfdata on driver fail Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 16/39] USB: serial: option: add ZLP support for 0x1bc7/0x9010 Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 17/39] usb: musb: fix idling for suspend after disconnect interrupt Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 18/39] usb: musb: Disable pullup at init Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 19/39] usb: musb: dma: Correct parameter passed to IRQ handler Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 20/39] staging: comedi: adv_pci1710: fix AI channels 16-31 for PCI-1713 Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 21/39] HID: hid-input: clear unmapped usages Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 22/39] Input: add safety guards to input_set_keycode() Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 23/39] drm/fb-helper: Round up bits_per_pixel if possible Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 24/39] drm/dp_mst: correct the shifting in DP_REMOTE_I2C_READ Greg Kroah-Hartman
2020-01-14 10:01 ` [PATCH 4.14 25/39] staging: rtl8188eu: Add device code for TP-Link TL-WN727N v5.21 Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 26/39] tty: link tty and port before configuring it as console Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 27/39] tty: always relink the port Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 28/39] mwifiex: fix possible heap overflow in mwifiex_process_country_ie() Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 29/39] mwifiex: pcie: Fix memory leak in mwifiex_pcie_alloc_cmdrsp_buf Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 30/39] scsi: bfa: release allocated memory in case of error Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 31/39] rtl8xxxu: prevent leaking urb Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 32/39] ath10k: fix memory leak Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 33/39] arm64: cpufeature: Avoid warnings due to unused symbols Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 34/39] HID: hiddev: fix mess in hiddev_open() Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 35/39] USB: Fix: Dont skip endpoint descriptors with maxpacket=0 Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 36/39] phy: cpcap-usb: Fix error path when no host driver is loaded Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 37/39] phy: cpcap-usb: Fix flakey host idling and enumerating of devices Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 38/39] netfilter: arp_tables: init netns pointer in xt_tgchk_param struct Greg Kroah-Hartman
2020-01-14 10:02 ` [PATCH 4.14 39/39] netfilter: ipset: avoid null deref when IPSET_ATTR_LINENO is present Greg Kroah-Hartman
2020-01-14 15:02 ` [PATCH 4.14 00/39] 4.14.165-stable review Jon Hunter
2020-01-14 18:15 ` Guenter Roeck
2020-01-14 20:27 ` shuah
2020-01-15  2:08 ` Daniel Díaz

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