From: Eddie James <eajames@linux.ibm.com>
To: openbmc@lists.ozlabs.org
Subject: [PATCH linux dev-5.10 27/35] net/ncsi: Avoid channel_monitor hrtimer deadlock
Date: Mon, 8 Mar 2021 16:54:11 -0600 [thread overview]
Message-ID: <20210308225419.46530-28-eajames@linux.ibm.com> (raw)
In-Reply-To: <20210308225419.46530-1-eajames@linux.ibm.com>
From: Milton Miller <miltonm@us.ibm.com>
Calling ncsi_stop_channel_monitor from channel_monitor is a guaranteed
deadlock on SMP because stop calls del_timer_sync on the timer that
inoked channel_monitor as its timer function.
Recognise the inherent race of marking the monitor disabled before
deleting the timer by just returning if enable was cleared. After
a timeout (the default case -- reset to START when response recieved)
just mark the monitor.enabled false.
If the channel has an entrie on the channel_queue list, or if the the
state is not ACTIVE or INACTIVE, then warn and mark the timer stopped
and don't restart, as the locking is broken somehow.
Fixes: 0795fb2021f0 ("net/ncsi: Stop monitor if channel times out or is inactive")
Signed-off-by: Milton Miller <miltonm@us.ibm.com>
---
net/ncsi/ncsi-manage.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/net/ncsi/ncsi-manage.c b/net/ncsi/ncsi-manage.c
index a9cb355324d1..5a2beaf874c7 100644
--- a/net/ncsi/ncsi-manage.c
+++ b/net/ncsi/ncsi-manage.c
@@ -105,13 +105,20 @@ static void ncsi_channel_monitor(struct timer_list *t)
monitor_state = nc->monitor.state;
spin_unlock_irqrestore(&nc->lock, flags);
- if (!enabled || chained) {
- ncsi_stop_channel_monitor(nc);
- return;
+ if (!enabled)
+ return; /* expected race disabling timer */
+ if (WARN_ON_ONCE(chained)) {
+ goto bad_state;
}
if (state != NCSI_CHANNEL_INACTIVE &&
state != NCSI_CHANNEL_ACTIVE) {
- ncsi_stop_channel_monitor(nc);
+bad_state:
+ netdev_warn(ndp->ndev.dev,
+ "Bad NCSI monitor state channel %d 0x%x %s queue\n",
+ nc->id, state, chained ? "on" : "off");
+ spin_lock_irqsave(&nc->lock, flags);
+ nc->monitor.enabled = false;
+ spin_unlock_irqrestore(&nc->lock, flags);
return;
}
@@ -136,10 +143,9 @@ static void ncsi_channel_monitor(struct timer_list *t)
ncsi_report_link(ndp, true);
ndp->flags |= NCSI_DEV_RESHUFFLE;
- ncsi_stop_channel_monitor(nc);
-
ncm = &nc->modes[NCSI_MODE_LINK];
spin_lock_irqsave(&nc->lock, flags);
+ nc->monitor.enabled = false;
nc->state = NCSI_CHANNEL_INVISIBLE;
ncm->data[2] &= ~0x1;
spin_unlock_irqrestore(&nc->lock, flags);
--
2.27.0
next prev parent reply other threads:[~2021-03-08 23:06 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-08 22:53 [PATCH linux dev-5.10 00/35] Rainier and Everest system updates Eddie James
2021-03-08 22:53 ` [PATCH linux dev-5.10 01/35] ARM: dts: aspeed: rainier: Add Operator Panel LEDs Eddie James
2021-03-12 0:05 ` Joel Stanley
2021-03-08 22:53 ` [PATCH linux dev-5.10 02/35] ARM: dts: aspeed: rainier: Add directly controlled LEDs Eddie James
2021-03-12 0:04 ` Joel Stanley
2021-03-08 22:53 ` [PATCH linux dev-5.10 03/35] ARM: dts: aspeed: rainier: Add gpio-keys-polled for fans Eddie James
2021-03-12 0:06 ` Joel Stanley
2021-03-08 22:53 ` [PATCH linux dev-5.10 04/35] ARM: dts: aspeed: rainier: Set MAX31785 config Eddie James
2021-03-12 0:07 ` Joel Stanley
2021-03-08 22:53 ` [PATCH linux dev-5.10 05/35] ARM: dts: aspeed: rainier: Add additional processor CFAMs Eddie James
2021-03-12 0:07 ` Joel Stanley
2021-03-08 22:53 ` [PATCH linux dev-5.10 06/35] ARM: dts: aspeed: rainier: Add leds that are off PCA9552 Eddie James
2021-03-12 0:09 ` Joel Stanley
2021-03-12 0:21 ` Milton Miller II
2021-03-12 0:30 ` Joel Stanley
[not found] ` <6ACEC474-8CFD-4BA9-B8FF-CCD41007AA67@linux.vnet.ibm.com>
2021-03-24 23:43 ` Joel Stanley
2021-04-26 5:59 ` vishwanatha subbanna
2021-04-27 21:22 ` Jacek Anaszewski
2021-03-08 22:53 ` [PATCH linux dev-5.10 07/35] ARM: dts: aspeed: rainier: Add leds that are off pic16f882 Eddie James
2021-03-12 0:10 ` Joel Stanley
2021-03-08 22:53 ` [PATCH linux dev-5.10 08/35] ARM: dts: aspeed: rainier: Add leds on optional DASD cards Eddie James
2021-03-12 0:10 ` Joel Stanley
2021-03-08 22:53 ` [PATCH linux dev-5.10 09/35] ARM: dts: aspeed: rainier: Add leds that are on optional PCI cable cards Eddie James
2021-03-12 0:11 ` Joel Stanley
2021-03-08 22:53 ` [PATCH linux dev-5.10 10/35] ARM: dts: aspeed: rainier: Add presence GPIOs Eddie James
2021-03-12 0:14 ` Joel Stanley
2021-03-08 22:53 ` [PATCH linux dev-5.10 11/35] ARM: dts: aspeed: rainier: Mark controllers as restricted Eddie James
2021-03-12 0:15 ` Joel Stanley
2021-03-08 22:53 ` [PATCH linux dev-5.10 12/35] ARM: dts: aspeed: rainier 4U: Fix fan configuration Eddie James
2021-03-12 0:17 ` Joel Stanley
2021-03-08 22:53 ` [PATCH linux dev-5.10 13/35] dt: bindings: mmc: Add phase control properties for the Aspeed SDHCI Eddie James
2021-03-12 0:19 ` Joel Stanley
2021-04-12 3:21 ` Andrew Jeffery
2021-03-08 22:53 ` [PATCH linux dev-5.10 14/35] mmc: sdhci: aspeed: Expose data sample phase delay tuning Eddie James
2021-03-08 22:53 ` [PATCH linux dev-5.10 15/35] ARM: dts: aspeed: tacoma: Add data sample phase delay for eMMC Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 16/35] ARM: dts: aspeed: tacoma: Remove CFAM reset GPIO Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 17/35] ARM: dts: aspeed: Everest: Add I2C components Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 18/35] ARM: dts: Aspeed: Everest: Add max31785 fan controller device Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 19/35] ARM: dts: Aspeed: Everest: Add FSI CFAMs and re-number engines Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 20/35] ARM: dts: Aspeed: Everest: Add pca9552 fan presence Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 21/35] ARM: dts: aspeed: everest: Add power supply i2c devices Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 22/35] ARM: dts: aspeed: everest: Add UCD90320 power sequencer Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 23/35] ARM: dts: aspeed: everest: GPIOs support Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 24/35] ARM: dts: Aspeed: Everest: Add RTC Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 25/35] ARM: dts: aspeed: rainier: Support pass 2 planar Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 26/35] fsi: scom: Handle FSI2PIB timeout Eddie James
2021-03-12 0:20 ` Joel Stanley
2021-03-08 22:54 ` Eddie James [this message]
2021-03-12 0:35 ` [PATCH linux dev-5.10 27/35] net/ncsi: Avoid channel_monitor hrtimer deadlock Joel Stanley
2021-03-08 22:54 ` [PATCH linux dev-5.10 28/35] ftgmac100: Restart MAC HW once Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 29/35] hwmon: (pmbus) Add a PMBUS_NO_CAPABILITY platform data flag Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 30/35] hwmon: (pmbus/ibm-cffps) Set the PMBUS_NO_CAPABILITY flag Eddie James
2021-03-12 0:23 ` Joel Stanley
2021-03-08 22:54 ` [PATCH linux dev-5.10 31/35] i2c: Allow throttling of transfers to client devices Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 32/35] pmbus: (ucd9000) Throttle SMBus transfers to avoid poor behaviour Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 33/35] pmbus: (core) Add a one-shot retry in pmbus_set_page() Eddie James
2021-03-09 20:21 ` Andrei Kartashev
2021-03-12 0:35 ` Joel Stanley
2021-03-08 22:54 ` [PATCH linux dev-5.10 34/35] pmbus: (max31785) Add a local pmbus_set_page() implementation Eddie James
2021-03-08 22:54 ` [PATCH linux dev-5.10 35/35] pmbus: (max31785) Retry enabling fans after writing MFR_FAN_CONFIG Eddie James
2021-03-12 0:37 ` [PATCH linux dev-5.10 00/35] Rainier and Everest system updates Joel Stanley
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