Dear RT folks!
I'm pleased to announce the v5.10-rc3-rt7 patch set.
Changes since v5.10-rc3-rt6:
- Mike Galbraith reported a lockdep warning triggered by the nouveau
driver with threaded interrupts.
- The recently reworked highmem code could trigger a warning on
certain ARM configurations. Reported upstream once parts of the code
hit linux-next. Patch by Thomas Gleixner.
- Update the softirq patches by Thomas Gleixner to newer version.
Known issues
- It has been pointed out that due to changes to the printk code the
internal buffer representation changed. This is only an issue if tools
like `crash' are used to extract the printk buffer from a kernel memory
image.
The delta patch against v5.10-rc3-rt6 is appended below and can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.10/incr/patch-5.10-rc3-rt6-rt7.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 v5.10-rc3-rt7
The RT patch against v5.10-rc3 can be found here:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patch-5.10-rc3-rt7.patch.xz
The split quilt queue is available at:
https://cdn.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10-rc3-rt7.tar.xz
Sebastian
diff --git a/arch/arm/include/asm/hardirq.h b/arch/arm/include/asm/hardirq.h
index b95848ed2bc7f..706efafbf9722 100644
--- a/arch/arm/include/asm/hardirq.h
+++ b/arch/arm/include/asm/hardirq.h
@@ -2,16 +2,11 @@
#ifndef __ASM_HARDIRQ_H
#define __ASM_HARDIRQ_H
-#include <linux/cache.h>
-#include <linux/threads.h>
#include <asm/irq.h>
-typedef struct {
- unsigned int __softirq_pending;
-} ____cacheline_aligned irq_cpustat_t;
-
-#include <linux/irq_cpustat.h> /* Standard mappings for irq_cpustat_t above */
-
#define __ARCH_IRQ_EXIT_IRQS_DISABLED 1
+#define ack_bad_irq ack_bad_irq
+
+#include <asm-generic/hardirq.h>
#endif /* __ASM_HARDIRQ_H */
diff --git a/arch/arm/include/asm/irq.h b/arch/arm/include/asm/irq.h
index 46d41140df27d..1cbcc462b07e8 100644
--- a/arch/arm/include/asm/irq.h
+++ b/arch/arm/include/asm/irq.h
@@ -31,6 +31,8 @@ void handle_IRQ(unsigned int, struct pt_regs *);
void init_IRQ(void);
#ifdef CONFIG_SMP
+#include <linux/cpumask.h>
+
extern void arch_trigger_cpumask_backtrace(const cpumask_t *mask,
bool exclude_self);
#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
diff --git a/arch/arm64/include/asm/hardirq.h b/arch/arm64/include/asm/hardirq.h
index 5ffa4bacdad38..cbfa7b6f2e098 100644
--- a/arch/arm64/include/asm/hardirq.h
+++ b/arch/arm64/include/asm/hardirq.h
@@ -13,11 +13,8 @@
#include <asm/kvm_arm.h>
#include <asm/sysreg.h>
-typedef struct {
- unsigned int __softirq_pending;
-} ____cacheline_aligned irq_cpustat_t;
-
-#include <linux/irq_cpustat.h> /* Standard mappings for irq_cpustat_t above */
+#define ack_bad_irq ack_bad_irq
+#include <asm-generic/hardirq.h>
#define __ARCH_IRQ_EXIT_IRQS_DISABLED 1
diff --git a/arch/parisc/include/asm/hardirq.h b/arch/parisc/include/asm/hardirq.h
index 7f7039516e53f..fad29aa6f45fa 100644
--- a/arch/parisc/include/asm/hardirq.h
+++ b/arch/parisc/include/asm/hardirq.h
@@ -32,7 +32,6 @@ typedef struct {
DECLARE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
#define __ARCH_IRQ_STAT
-#define __IRQ_STAT(cpu, member) (irq_stat[cpu].member)
#define inc_irq_stat(member) this_cpu_inc(irq_stat.member)
#define __inc_irq_stat(member) __this_cpu_inc(irq_stat.member)
#define ack_bad_irq(irq) WARN(1, "unexpected IRQ trap at vector %02x\n", irq)
diff --git a/arch/sh/include/asm/hardirq.h b/arch/sh/include/asm/hardirq.h
index edaea3559a232..9fe4495a8e90b 100644
--- a/arch/sh/include/asm/hardirq.h
+++ b/arch/sh/include/asm/hardirq.h
@@ -2,16 +2,10 @@
#ifndef __ASM_SH_HARDIRQ_H
#define __ASM_SH_HARDIRQ_H
-#include <linux/threads.h>
-#include <linux/irq.h>
-
-typedef struct {
- unsigned int __softirq_pending;
- unsigned int __nmi_count; /* arch dependent */
-} ____cacheline_aligned irq_cpustat_t;
-
-#include <linux/irq_cpustat.h> /* Standard mappings for irq_cpustat_t above */
-
extern void ack_bad_irq(unsigned int irq);
+#define ack_bad_irq ack_bad_irq
+#define ARCH_WANTS_NMI_IRQSTAT
+
+#include <asm-generic/hardirq.h>
#endif /* __ASM_SH_HARDIRQ_H */
diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
index c4e46252377ed..9d2e4026be961 100644
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -44,7 +44,7 @@ int arch_show_interrupts(struct seq_file *p, int prec)
seq_printf(p, "%*s: ", prec, "NMI");
for_each_online_cpu(j)
- seq_printf(p, "%10u ", nmi_count(j));
+ seq_printf(p, "%10u ", per_cpu(irq_stat.__nmi_count, j);
seq_printf(p, " Non-maskable interrupts\n");
seq_printf(p, "%*s: %10u\n", prec, "ERR", atomic_read(&irq_err_count));
diff --git a/arch/sh/kernel/traps.c b/arch/sh/kernel/traps.c
index 9c3d32b80038a..f5beecdac6938 100644
--- a/arch/sh/kernel/traps.c
+++ b/arch/sh/kernel/traps.c
@@ -186,7 +186,7 @@ BUILD_TRAP_HANDLER(nmi)
arch_ftrace_nmi_enter();
nmi_enter();
- nmi_count(cpu)++;
+ this_cpu_inc(irq_stat.__nmi_count);
switch (notify_die(DIE_NMI, "NMI", regs, 0, vec & 0xff, SIGINT)) {
case NOTIFY_OK:
diff --git a/arch/um/include/asm/hardirq.h b/arch/um/include/asm/hardirq.h
index b426796d26fd7..52e2c36267a93 100644
--- a/arch/um/include/asm/hardirq.h
+++ b/arch/um/include/asm/hardirq.h
@@ -2,22 +2,7 @@
#ifndef __ASM_UM_HARDIRQ_H
#define __ASM_UM_HARDIRQ_H
-#include <linux/cache.h>
-#include <linux/threads.h>
-
-typedef struct {
- unsigned int __softirq_pending;
-} ____cacheline_aligned irq_cpustat_t;
-
-#include <linux/irq_cpustat.h> /* Standard mappings for irq_cpustat_t above */
-#include <linux/irq.h>
-
-#ifndef ack_bad_irq
-static inline void ack_bad_irq(unsigned int irq)
-{
- printk(KERN_CRIT "unexpected IRQ trap at vector %02x\n", irq);
-}
-#endif
+#include <asm-generic/hardirq.h>
#define __ARCH_IRQ_EXIT_IRQS_DISABLED 1
diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h
index 22a39b72ce93f..b0ce938bbdb71 100644
--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -30,23 +30,32 @@ extern void kernel_fpu_resched(void);
* A context switch will (and softirq might) save CPU's FPU registers to
* fpu->state and set TIF_NEED_FPU_LOAD leaving CPU's FPU registers in
* a random state.
+ *
+ * local_bh_disable() protects against both preemption and soft interrupts
+ * on !RT kernels.
+ *
+ * On RT kernels local_bh_disable() is not sufficient because it only
+ * serializes soft interrupt related sections via a local lock, but stays
+ * preemptible. Disabling preemption is the right choice here as bottom
+ * half processing is always in thread context on RT kernels so it
+ * implicitly prevents bottom half processing as well.
+ *
+ * Disabling preemption also serializes against kernel_fpu_begin().
*/
static inline void fpregs_lock(void)
{
- preempt_disable();
- /*
- * On RT disabling preemption is good enough because bottom halfs
- * are always running in thread context.
- */
if (!IS_ENABLED(CONFIG_PREEMPT_RT))
local_bh_disable();
+ else
+ preempt_disable();
}
static inline void fpregs_unlock(void)
{
if (!IS_ENABLED(CONFIG_PREEMPT_RT))
local_bh_enable();
- preempt_enable();
+ else
+ preempt_enable();
}
#ifdef CONFIG_X86_DEBUG_FPU
diff --git a/include/asm-generic/hardirq.h b/include/asm-generic/hardirq.h
index d14214dfc10b3..7317e8258b486 100644
--- a/include/asm-generic/hardirq.h
+++ b/include/asm-generic/hardirq.h
@@ -7,9 +7,13 @@
typedef struct {
unsigned int __softirq_pending;
+#ifdef ARCH_WANTS_NMI_IRQSTAT
+ unsigned int __nmi_count;
+#endif
} ____cacheline_aligned irq_cpustat_t;
-#include <linux/irq_cpustat.h> /* Standard mappings for irq_cpustat_t above */
+DECLARE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat);
+
#include <linux/irq.h>
#ifndef ack_bad_irq
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 41408d5e40149..b14fb2a2a9c56 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -6,9 +6,9 @@
#include <linux/preempt.h>
#include <linux/lockdep.h>
#include <linux/ftrace_irq.h>
+#include <linux/sched.h>
#include <linux/vtime.h>
#include <asm/hardirq.h>
-#include <linux/sched.h>
extern void synchronize_irq(unsigned int irq);
extern bool synchronize_hardirq(unsigned int irq);
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index fa0a1ec9cb691..e65df3c95bc55 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -665,6 +665,7 @@ static inline void tasklet_unlock(struct tasklet_struct *t)
smp_mb__before_atomic();
clear_bit(TASKLET_STATE_RUN, &(t)->state);
}
+
void tasklet_unlock_wait(struct tasklet_struct *t);
#else
static inline int tasklet_trylock(struct tasklet_struct *t) { return 1; }
diff --git a/include/linux/irq_cpustat.h b/include/linux/irq_cpustat.h
deleted file mode 100644
index 6e8895cd4d926..0000000000000
--- a/include/linux/irq_cpustat.h
+++ /dev/null
@@ -1,28 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __irq_cpustat_h
-#define __irq_cpustat_h
-
-/*
- * Contains default mappings for irq_cpustat_t, used by almost every
- * architecture. Some arch (like s390) have per cpu hardware pages and
- * they define their own mappings for irq_stat.
- *
- * Keith Owens <kaos@xxxxxxxxxx> July 2000.
- */
-
-
-/*
- * Simple wrappers reducing source bloat. Define all irq_stat fields
- * here, even ones that are arch dependent. That way we get common
- * definitions instead of differing sets for each arch.
- */
-
-#ifndef __ARCH_IRQ_STAT
-DECLARE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat); /* defined in asm/hardirq.h */
-#define __IRQ_STAT(cpu, member) (per_cpu(irq_stat.member, cpu))
-#endif
-
-/* arch dependent irq_stat fields */
-#define nmi_count(cpu) __IRQ_STAT((cpu), __nmi_count) /* i386 */
-
-#endif /* __irq_cpustat_h */
diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 83b34cb809155..af39859f02ee1 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -77,34 +77,37 @@
/* preempt_count() and related functions, depends on PREEMPT_NEED_RESCHED */
#include <asm/preempt.h>
-#define pc_nmi_count() (preempt_count() & NMI_MASK)
-#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
+#define nmi_count() (preempt_count() & NMI_MASK)
+#define hardirq_count() (preempt_count() & HARDIRQ_MASK)
#ifdef CONFIG_PREEMPT_RT
# define softirq_count() (current->softirq_disable_cnt & SOFTIRQ_MASK)
#else
# define softirq_count() (preempt_count() & SOFTIRQ_MASK)
#endif
-#define irq_count() (pc_nmi_count() | hardirq_count() | softirq_count())
+#define irq_count() (nmi_count() | hardirq_count() | softirq_count())
/*
- * Are we doing bottom half or hardware interrupt processing?
+ * Macros to retrieve the current execution context:
*
- * in_irq() - We're in (hard) IRQ context
+ * in_nmi() - We're in NMI context
+ * in_hardirq() - We're in hard IRQ context
+ * in_serving_softirq() - We're in softirq context
+ * in_task() - We're in task context
+ */
+#define in_nmi() (nmi_count())
+#define in_hardirq() (hardirq_count())
+#define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET)
+#define in_task() (!(in_nmi() | in_hardirq() | in_serving_softirq()))
+
+/*
+ * The following macros are deprecated and should not be used in new code:
+ * in_irq() - Obsolete version of in_hardirq()
* in_softirq() - We have BH disabled, or are processing softirqs
* in_interrupt() - We're in NMI,IRQ,SoftIRQ context or have BH disabled
- * in_serving_softirq() - We're in softirq context
- * in_nmi() - We're in NMI context
- * in_task() - We're in task context
- *
- * Note: due to the BH disabled confusion: in_softirq(),in_interrupt() really
- * should not be used in new code.
*/
-#define in_nmi() (pc_nmi_count())
#define in_irq() (hardirq_count())
-#define in_interrupt() (irq_count())
#define in_softirq() (softirq_count())
-#define in_serving_softirq() (softirq_count() & SOFTIRQ_OFFSET)
-#define in_task() (!(irq_count() & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)))
+#define in_interrupt() (irq_count())
/*
* The preempt_count offset after preempt_disable();
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 67dc04573ae35..ef4c1343bd0ca 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1155,6 +1155,8 @@ static int irq_thread(void *data)
irqreturn_t (*handler_fn)(struct irq_desc *desc,
struct irqaction *action);
+ sched_set_fifo(current);
+
if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
&action->thread_flags))
handler_fn = irq_forced_thread_fn;
@@ -1326,8 +1328,6 @@ setup_irq_thread(struct irqaction *new, unsigned int irq, bool secondary)
if (IS_ERR(t))
return PTR_ERR(t);
- sched_set_fifo(t);
-
/*
* We keep the reference to the task struct even if
* the thread dies to avoid that the interrupt code
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 933a625621b8d..4a31127c6efbf 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -243,6 +243,7 @@ EXPORT_SYMBOL_GPL(kthread_parkme);
static int kthread(void *_create)
{
+ static const struct sched_param param = { .sched_priority = 0 };
/* Copy data: it's on kthread's stack */
struct kthread_create_info *create = _create;
int (*threadfn)(void *data) = create->threadfn;
@@ -273,6 +274,13 @@ static int kthread(void *_create)
init_completion(&self->parked);
current->vfork_done = &self->exited;
+ /*
+ * The new thread inherited kthreadd's priority and CPU mask. Reset
+ * back to default in case they have been changed.
+ */
+ sched_setscheduler_nocheck(current, SCHED_NORMAL, ¶m);
+ set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_KTHREAD));
+
/* OK, tell user we're spawned, wait for stop or wakeup */
__set_current_state(TASK_UNINTERRUPTIBLE);
create->result = current;
@@ -370,7 +378,6 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data),
}
task = create->result;
if (!IS_ERR(task)) {
- static const struct sched_param param = { .sched_priority = 0 };
char name[TASK_COMM_LEN];
/*
@@ -379,13 +386,6 @@ struct task_struct *__kthread_create_on_node(int (*threadfn)(void *data),
*/
vsnprintf(name, sizeof(name), namefmt, args);
set_task_comm(task, name);
- /*
- * root may have changed our (kthreadd's) priority or CPU mask.
- * The kernel thread should not inherit these properties.
- */
- sched_setscheduler_nocheck(task, SCHED_NORMAL, ¶m);
- set_cpus_allowed_ptr(task,
- housekeeping_cpumask(HK_FLAG_KTHREAD));
}
kfree(create);
return task;
diff --git a/kernel/softirq.c b/kernel/softirq.c
index a02735d4d1e9f..4406cdaa84670 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -158,7 +158,7 @@ void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
unsigned long flags;
int newcnt;
- WARN_ON_ONCE(in_irq());
+ WARN_ON_ONCE(in_hardirq());
/* First entry of a task into a BH disabled section? */
if (!current->softirq_disable_cnt) {
@@ -314,11 +314,10 @@ static inline bool should_wake_ksoftirqd(void)
#else /* CONFIG_PREEMPT_RT */
/*
- * This one is for softirq.c-internal use,
- * where hardirqs are disabled legitimately:
+ * This one is for softirq.c-internal use, where hardirqs are disabled
+ * legitimately:
*/
#ifdef CONFIG_TRACE_IRQFLAGS
-
void __local_bh_disable_ip(unsigned long ip, unsigned int cnt)
{
unsigned long flags;
@@ -440,6 +439,11 @@ static inline void ksoftirqd_run_end(void)
local_irq_enable();
}
+static inline bool should_wake_ksoftirqd(void)
+{
+ return true;
+}
+
static inline void invoke_softirq(void)
{
if (ksoftirqd_running(local_softirq_pending()))
@@ -466,7 +470,23 @@ static inline void invoke_softirq(void)
}
}
-static inline bool should_wake_ksoftirqd(void) { return true; }
+asmlinkage __visible void do_softirq(void)
+{
+ __u32 pending;
+ unsigned long flags;
+
+ if (in_interrupt())
+ return;
+
+ local_irq_save(flags);
+
+ pending = local_softirq_pending();
+
+ if (pending && !ksoftirqd_running(pending))
+ do_softirq_own_stack();
+
+ local_irq_restore(flags);
+}
#endif /* !CONFIG_PREEMPT_RT */
@@ -595,26 +615,6 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)
current_restore_flags(old_flags, PF_MEMALLOC);
}
-#ifndef CONFIG_PREEMPT_RT
-asmlinkage __visible void do_softirq(void)
-{
- __u32 pending;
- unsigned long flags;
-
- if (in_interrupt())
- return;
-
- local_irq_save(flags);
-
- pending = local_softirq_pending();
-
- if (pending && !ksoftirqd_running(pending))
- do_softirq_own_stack();
-
- local_irq_restore(flags);
-}
-#endif
-
/**
* irq_enter_rcu - Enter an interrupt context with RCU watching
*/
diff --git a/localversion-rt b/localversion-rt
index 8fc605d806670..045478966e9f1 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt6
+-rt7
diff --git a/mm/highmem.c b/mm/highmem.c
index 8db577e5290cc..72b9a2d95c72a 100644
--- a/mm/highmem.c
+++ b/mm/highmem.c
@@ -422,12 +422,15 @@ static inline void *arch_kmap_local_high_get(struct page *page)
#endif
/* Unmap a local mapping which was obtained by kmap_high_get() */
-static inline void kmap_high_unmap_local(unsigned long vaddr)
+static inline bool kmap_high_unmap_local(unsigned long vaddr)
{
#ifdef ARCH_NEEDS_KMAP_HIGH_GET
- if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP))
+ if (vaddr >= PKMAP_ADDR(0) && vaddr < PKMAP_ADDR(LAST_PKMAP)) {
kunmap_high(pte_page(pkmap_page_table[PKMAP_NR(vaddr)]));
+ return true;
+ }
#endif
+ return false;
}
static inline int kmap_local_calc_idx(int idx)
@@ -493,10 +496,14 @@ void kunmap_local_indexed(void *vaddr)
if (addr < __fix_to_virt(FIX_KMAP_END) ||
addr > __fix_to_virt(FIX_KMAP_BEGIN)) {
- WARN_ON_ONCE(addr < PAGE_OFFSET);
-
- /* Handle mappings which were obtained by kmap_high_get() */
- kmap_high_unmap_local(addr);
+ /*
+ * Handle mappings which were obtained by kmap_high_get()
+ * first as the virtual address of such mappings is below
+ * PAGE_OFFSET. Warn for all other addresses which are in
+ * the user space part of the virtual address space.
+ */
+ if (!kmap_high_unmap_local(addr))
+ WARN_ON_ONCE(addr < PAGE_OFFSET);
return;
}
