[ANNOUNCE] v5.11-rc5-rt3

From: Sebastian Andrzej Siewior
Date: Fri Jan 29 2021 - 14:24:21 EST

Dear RT folks!

I'm pleased to announce the v5.11-rc5-rt3 patch set.

Changes since v5.11-rc5-rt2:

- Update the work-in-progress softirq patch. One difference is that
tasklet_disable() becomes now sleeping if the tasklet is running
instead busy-spinning until it is done. Driver which invoke the
function in atomic context on !RT have been converted.

Known issues
- kdb/kgdb can easily deadlock.
- kmsg dumpers expecting not to be called in parallel can clobber
their temp buffer.
- netconsole triggers WARN.

The delta patch against v5.11-rc5-rt2 is appended below and can be found here:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.11/incr/patch-5.11-rc5-rt2-rt3.patch.xz

You can get this release via the git tree at:

git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git v5.11-rc5-rt3

The RT patch against v5.11-rc5 can be found here:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.11/older/patch-5.11-rc5-rt3.patch.xz

The split quilt queue is available at:

https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.11/older/patches-5.11-rc5-rt3.tar.xz

Sebastian

diff --git a/drivers/atm/eni.c b/drivers/atm/eni.c
index 316a9947541fe..e96a4e8a4a10c 100644
--- a/drivers/atm/eni.c
+++ b/drivers/atm/eni.c
@@ -2054,7 +2054,7 @@ static int eni_send(struct atm_vcc *vcc,struct sk_buff *skb)
}
submitted++;
ATM_SKB(skb)->vcc = vcc;
- tasklet_disable(&ENI_DEV(vcc->dev)->task);
+ tasklet_disable_in_atomic(&ENI_DEV(vcc->dev)->task);
res = do_tx(skb);
tasklet_enable(&ENI_DEV(vcc->dev)->task);
if (res == enq_ok) return 0;
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 9811c40956e54..17c9d825188bb 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -2545,7 +2545,7 @@ static int ohci_cancel_packet(struct fw_card *card, struct fw_packet *packet)
struct driver_data *driver_data = packet->driver_data;
int ret = -ENOENT;

- tasklet_disable(&ctx->tasklet);
+ tasklet_disable_in_atomic(&ctx->tasklet);

if (packet->ack != 0)
goto out;
@@ -3465,7 +3465,7 @@ static int ohci_flush_iso_completions(struct fw_iso_context *base)
struct iso_context *ctx = container_of(base, struct iso_context, base);
int ret = 0;

- tasklet_disable(&ctx->context.tasklet);
+ tasklet_disable_in_atomic(&ctx->context.tasklet);

if (!test_and_set_bit_lock(0, &ctx->flushing_completions)) {
context_tasklet((unsigned long)&ctx->context);
diff --git a/drivers/net/arcnet/arc-rimi.c b/drivers/net/arcnet/arc-rimi.c
index 98df38fe553ce..12d085405bd05 100644
--- a/drivers/net/arcnet/arc-rimi.c
+++ b/drivers/net/arcnet/arc-rimi.c
@@ -332,7 +332,7 @@ static int __init arc_rimi_init(void)
dev->irq = 9;

if (arcrimi_probe(dev)) {
- free_netdev(dev);
+ free_arcdev(dev);
return -EIO;
}

@@ -349,7 +349,7 @@ static void __exit arc_rimi_exit(void)
iounmap(lp->mem_start);
release_mem_region(dev->mem_start, dev->mem_end - dev->mem_start + 1);
free_irq(dev->irq, dev);
- free_netdev(dev);
+ free_arcdev(dev);
}

#ifndef MODULE
diff --git a/drivers/net/arcnet/arcdevice.h b/drivers/net/arcnet/arcdevice.h
index 22a49c6d7ae6e..5d4a4c7efbbff 100644
--- a/drivers/net/arcnet/arcdevice.h
+++ b/drivers/net/arcnet/arcdevice.h
@@ -298,6 +298,10 @@ struct arcnet_local {

int excnak_pending; /* We just got an excesive nak interrupt */

+ /* RESET flag handling */
+ int reset_in_progress;
+ struct work_struct reset_work;
+
struct {
uint16_t sequence; /* sequence number (incs with each packet) */
__be16 aborted_seq;
@@ -350,7 +354,9 @@ void arcnet_dump_skb(struct net_device *dev, struct sk_buff *skb, char *desc)

void arcnet_unregister_proto(struct ArcProto *proto);
irqreturn_t arcnet_interrupt(int irq, void *dev_id);
+
struct net_device *alloc_arcdev(const char *name);
+void free_arcdev(struct net_device *dev);

int arcnet_open(struct net_device *dev);
int arcnet_close(struct net_device *dev);
diff --git a/drivers/net/arcnet/arcnet.c b/drivers/net/arcnet/arcnet.c
index e04efc0a5c977..d76dd7d14299e 100644
--- a/drivers/net/arcnet/arcnet.c
+++ b/drivers/net/arcnet/arcnet.c
@@ -387,10 +387,44 @@ static void arcnet_timer(struct timer_list *t)
struct arcnet_local *lp = from_timer(lp, t, timer);
struct net_device *dev = lp->dev;

- if (!netif_carrier_ok(dev)) {
+ spin_lock_irq(&lp->lock);
+
+ if (!lp->reset_in_progress && !netif_carrier_ok(dev)) {
netif_carrier_on(dev);
netdev_info(dev, "link up\n");
}
+
+ spin_unlock_irq(&lp->lock);
+}
+
+static void reset_device_work(struct work_struct *work)
+{
+ struct arcnet_local *lp;
+ struct net_device *dev;
+
+ lp = container_of(work, struct arcnet_local, reset_work);
+ dev = lp->dev;
+
+ /* Do not bring the network interface back up if an ifdown
+ * was already done.
+ */
+ if (!netif_running(dev) || !lp->reset_in_progress)
+ return;
+
+ rtnl_lock();
+
+ /* Do another check, in case of an ifdown that was triggered in
+ * the small race window between the exit condition above and
+ * acquiring RTNL.
+ */
+ if (!netif_running(dev) || !lp->reset_in_progress)
+ goto out;
+
+ dev_close(dev);
+ dev_open(dev, NULL);
+
+out:
+ rtnl_unlock();
}

static void arcnet_reply_tasklet(unsigned long data)
@@ -452,12 +486,25 @@ struct net_device *alloc_arcdev(const char *name)
lp->dev = dev;
spin_lock_init(&lp->lock);
timer_setup(&lp->timer, arcnet_timer, 0);
+ INIT_WORK(&lp->reset_work, reset_device_work);
}

return dev;
}
EXPORT_SYMBOL(alloc_arcdev);

+void free_arcdev(struct net_device *dev)
+{
+ struct arcnet_local *lp = netdev_priv(dev);
+
+ /* Do not cancel this at ->ndo_close(), as the workqueue itself
+ * indirectly calls the ifdown path through dev_close().
+ */
+ cancel_work_sync(&lp->reset_work);
+ free_netdev(dev);
+}
+EXPORT_SYMBOL(free_arcdev);
+
/* Open/initialize the board. This is called sometime after booting when
* the 'ifconfig' program is run.
*
@@ -587,6 +634,10 @@ int arcnet_close(struct net_device *dev)

/* shut down the card */
lp->hw.close(dev);
+
+ /* reset counters */
+ lp->reset_in_progress = 0;
+
module_put(lp->hw.owner);
return 0;
}
@@ -820,6 +871,9 @@ irqreturn_t arcnet_interrupt(int irq, void *dev_id)

spin_lock_irqsave(&lp->lock, flags);

+ if (lp->reset_in_progress)
+ goto out;
+
/* RESET flag was enabled - if device is not running, we must
* clear it right away (but nothing else).
*/
@@ -852,11 +906,14 @@ irqreturn_t arcnet_interrupt(int irq, void *dev_id)
if (status & RESETflag) {
arc_printk(D_NORMAL, dev, "spurious reset (status=%Xh)\n",
status);
- arcnet_close(dev);
- arcnet_open(dev);
+
+ lp->reset_in_progress = 1;
+ netif_stop_queue(dev);
+ netif_carrier_off(dev);
+ schedule_work(&lp->reset_work);

/* get out of the interrupt handler! */
- break;
+ goto out;
}
/* RX is inhibited - we must have received something.
* Prepare to receive into the next buffer.
@@ -1052,6 +1109,7 @@ irqreturn_t arcnet_interrupt(int irq, void *dev_id)
udelay(1);
lp->hw.intmask(dev, lp->intmask);

+out:
spin_unlock_irqrestore(&lp->lock, flags);
return retval;
}
diff --git a/drivers/net/arcnet/com20020-isa.c b/drivers/net/arcnet/com20020-isa.c
index f983c4ce6b07f..be618e4b9ed5e 100644
--- a/drivers/net/arcnet/com20020-isa.c
+++ b/drivers/net/arcnet/com20020-isa.c
@@ -169,7 +169,7 @@ static int __init com20020_init(void)
dev->irq = 9;

if (com20020isa_probe(dev)) {
- free_netdev(dev);
+ free_arcdev(dev);
return -EIO;
}

@@ -182,7 +182,7 @@ static void __exit com20020_exit(void)
unregister_netdev(my_dev);
free_irq(my_dev->irq, my_dev);
release_region(my_dev->base_addr, ARCNET_TOTAL_SIZE);
- free_netdev(my_dev);
+ free_arcdev(my_dev);
}

#ifndef MODULE
diff --git a/drivers/net/arcnet/com20020-pci.c b/drivers/net/arcnet/com20020-pci.c
index eb7f76753c9c0..8bdc44b7e09a1 100644
--- a/drivers/net/arcnet/com20020-pci.c
+++ b/drivers/net/arcnet/com20020-pci.c
@@ -291,7 +291,7 @@ static void com20020pci_remove(struct pci_dev *pdev)

unregister_netdev(dev);
free_irq(dev->irq, dev);
- free_netdev(dev);
+ free_arcdev(dev);
}
}

diff --git a/drivers/net/arcnet/com20020_cs.c b/drivers/net/arcnet/com20020_cs.c
index cf607ffcf358e..9cc5eb6a8e905 100644
--- a/drivers/net/arcnet/com20020_cs.c
+++ b/drivers/net/arcnet/com20020_cs.c
@@ -177,7 +177,7 @@ static void com20020_detach(struct pcmcia_device *link)
dev = info->dev;
if (dev) {
dev_dbg(&link->dev, "kfree...\n");
- free_netdev(dev);
+ free_arcdev(dev);
}
dev_dbg(&link->dev, "kfree2...\n");
kfree(info);
diff --git a/drivers/net/arcnet/com90io.c b/drivers/net/arcnet/com90io.c
index cf214b7306715..3856b447d38ed 100644
--- a/drivers/net/arcnet/com90io.c
+++ b/drivers/net/arcnet/com90io.c
@@ -396,7 +396,7 @@ static int __init com90io_init(void)
err = com90io_probe(dev);

if (err) {
- free_netdev(dev);
+ free_arcdev(dev);
return err;
}

@@ -419,7 +419,7 @@ static void __exit com90io_exit(void)

free_irq(dev->irq, dev);
release_region(dev->base_addr, ARCNET_TOTAL_SIZE);
- free_netdev(dev);
+ free_arcdev(dev);
}

module_init(com90io_init)
diff --git a/drivers/net/arcnet/com90xx.c b/drivers/net/arcnet/com90xx.c
index 3dc3d533cb19a..d8dfb9ea0de89 100644
--- a/drivers/net/arcnet/com90xx.c
+++ b/drivers/net/arcnet/com90xx.c
@@ -554,7 +554,7 @@ static int __init com90xx_found(int ioaddr, int airq, u_long shmem,
err_release_mem:
release_mem_region(dev->mem_start, dev->mem_end - dev->mem_start + 1);
err_free_dev:
- free_netdev(dev);
+ free_arcdev(dev);
return -EIO;
}

@@ -672,7 +672,7 @@ static void __exit com90xx_exit(void)
release_region(dev->base_addr, ARCNET_TOTAL_SIZE);
release_mem_region(dev->mem_start,
dev->mem_end - dev->mem_start + 1);
- free_netdev(dev);
+ free_arcdev(dev);
}
}

diff --git a/drivers/net/ethernet/dlink/sundance.c b/drivers/net/ethernet/dlink/sundance.c
index e3a8858915b37..df0eab479d512 100644
--- a/drivers/net/ethernet/dlink/sundance.c
+++ b/drivers/net/ethernet/dlink/sundance.c
@@ -963,7 +963,7 @@ static void tx_timeout(struct net_device *dev, unsigned int txqueue)
unsigned long flag;

netif_stop_queue(dev);
- tasklet_disable(&np->tx_tasklet);
+ tasklet_disable_in_atomic(&np->tx_tasklet);
iowrite16(0, ioaddr + IntrEnable);
printk(KERN_WARNING "%s: Transmit timed out, TxStatus %2.2x "
"TxFrameId %2.2x,"
diff --git a/drivers/net/ethernet/jme.c b/drivers/net/ethernet/jme.c
index e9efe074edc11..f1b9284e0bea8 100644
--- a/drivers/net/ethernet/jme.c
+++ b/drivers/net/ethernet/jme.c
@@ -1265,9 +1265,9 @@ jme_stop_shutdown_timer(struct jme_adapter *jme)
jwrite32f(jme, JME_APMC, apmc);
}

-static void jme_link_change_tasklet(struct tasklet_struct *t)
+static void jme_link_change_work(struct work_struct *work)
{
- struct jme_adapter *jme = from_tasklet(jme, t, linkch_task);
+ struct jme_adapter *jme = container_of(work, struct jme_adapter, linkch_task);
struct net_device *netdev = jme->dev;
int rc;

@@ -1510,7 +1510,7 @@ jme_intr_msi(struct jme_adapter *jme, u32 intrstat)
* all other events are ignored
*/
jwrite32(jme, JME_IEVE, intrstat);
- tasklet_schedule(&jme->linkch_task);
+ schedule_work(&jme->linkch_task);
goto out_reenable;
}

@@ -1832,7 +1832,6 @@ jme_open(struct net_device *netdev)
jme_clear_pm_disable_wol(jme);
JME_NAPI_ENABLE(jme);

- tasklet_setup(&jme->linkch_task, jme_link_change_tasklet);
tasklet_setup(&jme->txclean_task, jme_tx_clean_tasklet);
tasklet_setup(&jme->rxclean_task, jme_rx_clean_tasklet);
tasklet_setup(&jme->rxempty_task, jme_rx_empty_tasklet);
@@ -1920,7 +1919,7 @@ jme_close(struct net_device *netdev)

JME_NAPI_DISABLE(jme);

- tasklet_kill(&jme->linkch_task);
+ cancel_work_sync(&jme->linkch_task);
tasklet_kill(&jme->txclean_task);
tasklet_kill(&jme->rxclean_task);
tasklet_kill(&jme->rxempty_task);
@@ -3035,6 +3034,7 @@ jme_init_one(struct pci_dev *pdev,
atomic_set(&jme->rx_empty, 1);

tasklet_setup(&jme->pcc_task, jme_pcc_tasklet);
+ INIT_WORK(&jme->linkch_task, jme_link_change_work);
jme->dpi.cur = PCC_P1;

jme->reg_ghc = 0;
diff --git a/drivers/net/ethernet/jme.h b/drivers/net/ethernet/jme.h
index a2c3b00d939d0..2af76329b4a27 100644
--- a/drivers/net/ethernet/jme.h
+++ b/drivers/net/ethernet/jme.h
@@ -411,7 +411,7 @@ struct jme_adapter {
struct tasklet_struct rxempty_task;
struct tasklet_struct rxclean_task;
struct tasklet_struct txclean_task;
- struct tasklet_struct linkch_task;
+ struct work_struct linkch_task;
struct tasklet_struct pcc_task;
unsigned long flags;
u32 reg_txcs;
diff --git a/drivers/net/wireless/ath/ath9k/beacon.c b/drivers/net/wireless/ath/ath9k/beacon.c
index 71e2ada86793f..72e2e71aac0e6 100644
--- a/drivers/net/wireless/ath/ath9k/beacon.c
+++ b/drivers/net/wireless/ath/ath9k/beacon.c
@@ -251,7 +251,7 @@ void ath9k_beacon_ensure_primary_slot(struct ath_softc *sc)
int first_slot = ATH_BCBUF;
int slot;

- tasklet_disable(&sc->bcon_tasklet);
+ tasklet_disable_in_atomic(&sc->bcon_tasklet);

/* Find first taken slot. */
for (slot = 0; slot < ATH_BCBUF; slot++) {
diff --git a/drivers/pci/controller/pci-hyperv.c b/drivers/pci/controller/pci-hyperv.c
index 6db8d96a78ebc..316e8b9b13382 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -1458,7 +1458,7 @@ static void hv_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
* Prevents hv_pci_onchannelcallback() from running concurrently
* in the tasklet.
*/
- tasklet_disable(&channel->callback_event);
+ tasklet_disable_in_atomic(&channel->callback_event);

/*
* Since this function is called with IRQ locks held, can't
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 265bf231c0ad1..ed6e49bceff1a 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -669,17 +669,14 @@ static inline int tasklet_trylock(struct tasklet_struct *t)
return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
}

-static inline void tasklet_unlock(struct tasklet_struct *t)
-{
- smp_mb__before_atomic();
- clear_bit(TASKLET_STATE_RUN, &(t)->state);
-}
-
+void tasklet_unlock(struct tasklet_struct *t);
void tasklet_unlock_wait(struct tasklet_struct *t);
+void tasklet_unlock_spin_wait(struct tasklet_struct *t);
#else
static inline int tasklet_trylock(struct tasklet_struct *t) { return 1; }
static inline void tasklet_unlock(struct tasklet_struct *t) { }
static inline void tasklet_unlock_wait(struct tasklet_struct *t) { }
+static inline void tasklet_unlock_spin_wait(struct tasklet_struct *t) { }
#endif

extern void __tasklet_schedule(struct tasklet_struct *t);
@@ -704,6 +701,17 @@ static inline void tasklet_disable_nosync(struct tasklet_struct *t)
smp_mb__after_atomic();
}

+/*
+ * Do not use in new code. There is no real reason to invoke this from
+ * atomic contexts.
+ */
+static inline void tasklet_disable_in_atomic(struct tasklet_struct *t)
+{
+ tasklet_disable_nosync(t);
+ tasklet_unlock_spin_wait(t);
+ smp_mb();
+}
+
static inline void tasklet_disable(struct tasklet_struct *t)
{
tasklet_disable_nosync(t);
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 7bcc5442a97e3..8f4c141b20c05 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -26,6 +26,7 @@
#include <linux/smpboot.h>
#include <linux/tick.h>
#include <linux/irq.h>
+#include <linux/wait_bit.h>

#define CREATE_TRACE_POINTS
#include <trace/events/irq.h>
@@ -150,7 +151,7 @@ static DEFINE_PER_CPU(struct softirq_ctrl, softirq_ctrl) = {
*/
bool local_bh_blocked(void)
{
- return this_cpu_read(softirq_ctrl.cnt) != 0;
+ return __this_cpu_read(softirq_ctrl.cnt) != 0;
}

void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
@@ -224,7 +225,7 @@ void __local_bh_enable_ip(unsigned long ip, unsigned int cnt)
lockdep_assert_irqs_enabled();

local_irq_save(flags);
- curcnt = this_cpu_read(softirq_ctrl.cnt);
+ curcnt = __this_cpu_read(softirq_ctrl.cnt);

/*
* If this is not reenabling soft interrupts, no point in trying to
@@ -743,6 +744,16 @@ void __tasklet_hi_schedule(struct tasklet_struct *t)
}
EXPORT_SYMBOL(__tasklet_hi_schedule);

+static inline bool tasklet_clear_sched(struct tasklet_struct *t)
+{
+ if (test_and_clear_bit(TASKLET_STATE_SCHED, &t->state)) {
+ wake_up_var(&t->state);
+ return true;
+ }
+
+ return false;
+}
+
static void tasklet_action_common(struct softirq_action *a,
struct tasklet_head *tl_head,
unsigned int softirq_nr)
@@ -762,8 +773,7 @@ static void tasklet_action_common(struct softirq_action *a,

if (tasklet_trylock(t)) {
if (!atomic_read(&t->count)) {
- if (!test_and_clear_bit(TASKLET_STATE_SCHED,
- &t->state))
+ if (!tasklet_clear_sched(t))
BUG();
if (t->use_callback)
t->callback(t);
@@ -819,8 +829,11 @@ void tasklet_init(struct tasklet_struct *t,
EXPORT_SYMBOL(tasklet_init);

#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT)
-
-void tasklet_unlock_wait(struct tasklet_struct *t)
+/*
+ * Do not use in new code. There is no real reason to invoke this from
+ * atomic contexts.
+ */
+void tasklet_unlock_spin_wait(struct tasklet_struct *t)
{
while (test_bit(TASKLET_STATE_RUN, &(t)->state)) {
if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
@@ -838,7 +851,7 @@ void tasklet_unlock_wait(struct tasklet_struct *t)
}
}
}
-EXPORT_SYMBOL(tasklet_unlock_wait);
+EXPORT_SYMBOL(tasklet_unlock_spin_wait);
#endif

void tasklet_kill(struct tasklet_struct *t)
@@ -846,29 +859,31 @@ void tasklet_kill(struct tasklet_struct *t)
if (in_interrupt())
pr_notice("Attempt to kill tasklet from interrupt\n");

- while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) {
- do {
- if (IS_ENABLED(CONFIG_PREEMPT_RT)) {
- /*
- * Prevent a live lock when current
- * preempted soft interrupt processing or
- * prevents ksoftirqd from running. If the
- * tasklet runs on a different CPU then
- * this has no effect other than doing the
- * BH disable/enable dance for nothing.
- */
- local_bh_disable();
- local_bh_enable();
- } else {
- yield();
- }
- } while (test_bit(TASKLET_STATE_SCHED, &t->state));
- }
+ while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state))
+ wait_var_event(&t->state, !test_bit(TASKLET_STATE_SCHED, &t->state));
+
tasklet_unlock_wait(t);
- clear_bit(TASKLET_STATE_SCHED, &t->state);
+ tasklet_clear_sched(t);
}
EXPORT_SYMBOL(tasklet_kill);

+#ifdef CONFIG_SMP
+void tasklet_unlock(struct tasklet_struct *t)
+{
+ smp_mb__before_atomic();
+ clear_bit(TASKLET_STATE_RUN, &t->state);
+ smp_mb__after_atomic();
+ wake_up_var(&t->state);
+}
+EXPORT_SYMBOL_GPL(tasklet_unlock);
+
+void tasklet_unlock_wait(struct tasklet_struct *t)
+{
+ wait_var_event(&t->state, !test_bit(TASKLET_STATE_RUN, &t->state));
+}
+EXPORT_SYMBOL_GPL(tasklet_unlock_wait);
+#endif
+
void __init softirq_init(void)
{
int cpu;
diff --git a/localversion-rt b/localversion-rt
index c3054d08a1129..1445cd65885cd 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt2
+-rt3