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-rw-r--r--kernel/cpu.c10
-rw-r--r--kernel/fork.c15
-rw-r--r--kernel/hw_breakpoint.c56
-rw-r--r--kernel/kexec.c4
-rw-r--r--kernel/kgdb.c3
-rw-r--r--kernel/lockdep.c2
-rw-r--r--kernel/panic.c3
-rw-r--r--kernel/printk.c1
-rw-r--r--kernel/sched.c39
-rw-r--r--kernel/time/clockevents.c3
-rw-r--r--kernel/time/clocksource.c18
-rw-r--r--kernel/trace/Kconfig4
-rw-r--r--kernel/trace/ring_buffer.c24
-rw-r--r--kernel/trace/trace.c5
14 files changed, 133 insertions, 54 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 1c8ddd6ee940..677f25376a38 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -151,13 +151,13 @@ static inline void check_for_tasks(int cpu)
write_lock_irq(&tasklist_lock);
for_each_process(p) {
- if (task_cpu(p) == cpu &&
+ if (task_cpu(p) == cpu && p->state == TASK_RUNNING &&
(!cputime_eq(p->utime, cputime_zero) ||
!cputime_eq(p->stime, cputime_zero)))
- printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d\
- (state = %ld, flags = %x) \n",
- p->comm, task_pid_nr(p), cpu,
- p->state, p->flags);
+ printk(KERN_WARNING "Task %s (pid = %d) is on cpu %d "
+ "(state = %ld, flags = %x)\n",
+ p->comm, task_pid_nr(p), cpu,
+ p->state, p->flags);
}
write_unlock_irq(&tasklist_lock);
}
diff --git a/kernel/fork.c b/kernel/fork.c
index 5b2959b3ffc2..f88bd984df35 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1241,21 +1241,6 @@ static struct task_struct *copy_process(unsigned long clone_flags,
/* Need tasklist lock for parent etc handling! */
write_lock_irq(&tasklist_lock);
- /*
- * The task hasn't been attached yet, so its cpus_allowed mask will
- * not be changed, nor will its assigned CPU.
- *
- * The cpus_allowed mask of the parent may have changed after it was
- * copied first time - so re-copy it here, then check the child's CPU
- * to ensure it is on a valid CPU (and if not, just force it back to
- * parent's CPU). This avoids alot of nasty races.
- */
- p->cpus_allowed = current->cpus_allowed;
- p->rt.nr_cpus_allowed = current->rt.nr_cpus_allowed;
- if (unlikely(!cpu_isset(task_cpu(p), p->cpus_allowed) ||
- !cpu_online(task_cpu(p))))
- set_task_cpu(p, smp_processor_id());
-
/* CLONE_PARENT re-uses the old parent */
if (clone_flags & (CLONE_PARENT|CLONE_THREAD)) {
p->real_parent = current->real_parent;
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
index 50dbd5999588..8a5c7d55ac9f 100644
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -243,38 +243,70 @@ static void toggle_bp_slot(struct perf_event *bp, bool enable)
* ((per_cpu(nr_bp_flexible, *) > 1) + max(per_cpu(nr_cpu_bp_pinned, *))
* + max(per_cpu(nr_task_bp_pinned, *))) < HBP_NUM
*/
-int reserve_bp_slot(struct perf_event *bp)
+static int __reserve_bp_slot(struct perf_event *bp)
{
struct bp_busy_slots slots = {0};
- int ret = 0;
-
- mutex_lock(&nr_bp_mutex);
fetch_bp_busy_slots(&slots, bp);
/* Flexible counters need to keep at least one slot */
- if (slots.pinned + (!!slots.flexible) == HBP_NUM) {
- ret = -ENOSPC;
- goto end;
- }
+ if (slots.pinned + (!!slots.flexible) == HBP_NUM)
+ return -ENOSPC;
toggle_bp_slot(bp, true);
-end:
+ return 0;
+}
+
+int reserve_bp_slot(struct perf_event *bp)
+{
+ int ret;
+
+ mutex_lock(&nr_bp_mutex);
+
+ ret = __reserve_bp_slot(bp);
+
mutex_unlock(&nr_bp_mutex);
return ret;
}
+static void __release_bp_slot(struct perf_event *bp)
+{
+ toggle_bp_slot(bp, false);
+}
+
void release_bp_slot(struct perf_event *bp)
{
mutex_lock(&nr_bp_mutex);
- toggle_bp_slot(bp, false);
+ __release_bp_slot(bp);
mutex_unlock(&nr_bp_mutex);
}
+/*
+ * Allow the kernel debugger to reserve breakpoint slots without
+ * taking a lock using the dbg_* variant of for the reserve and
+ * release breakpoint slots.
+ */
+int dbg_reserve_bp_slot(struct perf_event *bp)
+{
+ if (mutex_is_locked(&nr_bp_mutex))
+ return -1;
+
+ return __reserve_bp_slot(bp);
+}
+
+int dbg_release_bp_slot(struct perf_event *bp)
+{
+ if (mutex_is_locked(&nr_bp_mutex))
+ return -1;
+
+ __release_bp_slot(bp);
+
+ return 0;
+}
int register_perf_hw_breakpoint(struct perf_event *bp)
{
@@ -296,6 +328,10 @@ int register_perf_hw_breakpoint(struct perf_event *bp)
if (!bp->attr.disabled || !bp->overflow_handler)
ret = arch_validate_hwbkpt_settings(bp, bp->ctx->task);
+ /* if arch_validate_hwbkpt_settings() fails then release bp slot */
+ if (ret)
+ release_bp_slot(bp);
+
return ret;
}
diff --git a/kernel/kexec.c b/kernel/kexec.c
index a9a93d9ee7a7..ef077fb73155 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -32,6 +32,7 @@
#include <linux/console.h>
#include <linux/vmalloc.h>
#include <linux/swap.h>
+#include <linux/kmsg_dump.h>
#include <asm/page.h>
#include <asm/uaccess.h>
@@ -1074,6 +1075,9 @@ void crash_kexec(struct pt_regs *regs)
if (mutex_trylock(&kexec_mutex)) {
if (kexec_crash_image) {
struct pt_regs fixed_regs;
+
+ kmsg_dump(KMSG_DUMP_KEXEC);
+
crash_setup_regs(&fixed_regs, regs);
crash_save_vmcoreinfo();
machine_crash_shutdown(&fixed_regs);
diff --git a/kernel/kgdb.c b/kernel/kgdb.c
index 2eb517e23514..c7ade62e4ef0 100644
--- a/kernel/kgdb.c
+++ b/kernel/kgdb.c
@@ -583,6 +583,9 @@ static void kgdb_wait(struct pt_regs *regs)
smp_wmb();
atomic_set(&cpu_in_kgdb[cpu], 1);
+ /* Disable any cpu specific hw breakpoints */
+ kgdb_disable_hw_debug(regs);
+
/* Wait till primary CPU is done with debugging */
while (atomic_read(&passive_cpu_wait[cpu]))
cpu_relax();
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 5feaddcdbe49..c62ec14609b9 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2147,7 +2147,7 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this,
return ret;
return print_irq_inversion_bug(curr, &root, target_entry,
- this, 1, irqclass);
+ this, 0, irqclass);
}
void print_irqtrace_events(struct task_struct *curr)
diff --git a/kernel/panic.c b/kernel/panic.c
index 5827f7b97254..c787333282b8 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -75,7 +75,6 @@ NORET_TYPE void panic(const char * fmt, ...)
dump_stack();
#endif
- kmsg_dump(KMSG_DUMP_PANIC);
/*
* If we have crashed and we have a crash kernel loaded let it handle
* everything else.
@@ -83,6 +82,8 @@ NORET_TYPE void panic(const char * fmt, ...)
*/
crash_kexec(NULL);
+ kmsg_dump(KMSG_DUMP_PANIC);
+
/*
* Note smp_send_stop is the usual smp shutdown function, which
* unfortunately means it may not be hardened to work in a panic
diff --git a/kernel/printk.c b/kernel/printk.c
index 17463ca2e229..1751c456b71f 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1467,6 +1467,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
static const char const *kmsg_reasons[] = {
[KMSG_DUMP_OOPS] = "oops",
[KMSG_DUMP_PANIC] = "panic",
+ [KMSG_DUMP_KEXEC] = "kexec",
};
static const char *kmsg_to_str(enum kmsg_dump_reason reason)
diff --git a/kernel/sched.c b/kernel/sched.c
index 4508fe7048be..3a8fb30a91b1 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2320,14 +2320,12 @@ static int select_fallback_rq(int cpu, struct task_struct *p)
}
/*
- * Called from:
+ * Gets called from 3 sites (exec, fork, wakeup), since it is called without
+ * holding rq->lock we need to ensure ->cpus_allowed is stable, this is done
+ * by:
*
- * - fork, @p is stable because it isn't on the tasklist yet
- *
- * - exec, @p is unstable, retry loop
- *
- * - wake-up, we serialize ->cpus_allowed against TASK_WAKING so
- * we should be good.
+ * exec: is unstable, retry loop
+ * fork & wake-up: serialize ->cpus_allowed against TASK_WAKING
*/
static inline
int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags)
@@ -2620,9 +2618,6 @@ void sched_fork(struct task_struct *p, int clone_flags)
if (p->sched_class->task_fork)
p->sched_class->task_fork(p);
-#ifdef CONFIG_SMP
- cpu = select_task_rq(p, SD_BALANCE_FORK, 0);
-#endif
set_task_cpu(p, cpu);
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
@@ -2652,6 +2647,21 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
{
unsigned long flags;
struct rq *rq;
+ int cpu = get_cpu();
+
+#ifdef CONFIG_SMP
+ /*
+ * Fork balancing, do it here and not earlier because:
+ * - cpus_allowed can change in the fork path
+ * - any previously selected cpu might disappear through hotplug
+ *
+ * We still have TASK_WAKING but PF_STARTING is gone now, meaning
+ * ->cpus_allowed is stable, we have preemption disabled, meaning
+ * cpu_online_mask is stable.
+ */
+ cpu = select_task_rq(p, SD_BALANCE_FORK, 0);
+ set_task_cpu(p, cpu);
+#endif
rq = task_rq_lock(p, &flags);
BUG_ON(p->state != TASK_WAKING);
@@ -2665,6 +2675,7 @@ void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
p->sched_class->task_woken(rq, p);
#endif
task_rq_unlock(rq, &flags);
+ put_cpu();
}
#ifdef CONFIG_PREEMPT_NOTIFIERS
@@ -7139,14 +7150,18 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
* the ->cpus_allowed mask from under waking tasks, which would be
* possible when we change rq->lock in ttwu(), so synchronize against
* TASK_WAKING to avoid that.
+ *
+ * Make an exception for freshly cloned tasks, since cpuset namespaces
+ * might move the task about, we have to validate the target in
+ * wake_up_new_task() anyway since the cpu might have gone away.
*/
again:
- while (p->state == TASK_WAKING)
+ while (p->state == TASK_WAKING && !(p->flags & PF_STARTING))
cpu_relax();
rq = task_rq_lock(p, &flags);
- if (p->state == TASK_WAKING) {
+ if (p->state == TASK_WAKING && !(p->flags & PF_STARTING)) {
task_rq_unlock(rq, &flags);
goto again;
}
diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 6f740d9f0948..d7395fdfb9f3 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -259,7 +259,8 @@ void clockevents_notify(unsigned long reason, void *arg)
cpu = *((int *)arg);
list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {
if (cpumask_test_cpu(cpu, dev->cpumask) &&
- cpumask_weight(dev->cpumask) == 1) {
+ cpumask_weight(dev->cpumask) == 1 &&
+ !tick_is_broadcast_device(dev)) {
BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
list_del(&dev->list);
}
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index e85c23404d34..13700833c181 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -343,7 +343,19 @@ static void clocksource_resume_watchdog(void)
{
unsigned long flags;
- spin_lock_irqsave(&watchdog_lock, flags);
+ /*
+ * We use trylock here to avoid a potential dead lock when
+ * kgdb calls this code after the kernel has been stopped with
+ * watchdog_lock held. When watchdog_lock is held we just
+ * return and accept, that the watchdog might trigger and mark
+ * the monitored clock source (usually TSC) unstable.
+ *
+ * This does not affect the other caller clocksource_resume()
+ * because at this point the kernel is UP, interrupts are
+ * disabled and nothing can hold watchdog_lock.
+ */
+ if (!spin_trylock_irqsave(&watchdog_lock, flags))
+ return;
clocksource_reset_watchdog();
spin_unlock_irqrestore(&watchdog_lock, flags);
}
@@ -458,8 +470,8 @@ void clocksource_resume(void)
* clocksource_touch_watchdog - Update watchdog
*
* Update the watchdog after exception contexts such as kgdb so as not
- * to incorrectly trip the watchdog.
- *
+ * to incorrectly trip the watchdog. This might fail when the kernel
+ * was stopped in code which holds watchdog_lock.
*/
void clocksource_touch_watchdog(void)
{
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig
index 6c22d8a2f289..60e2ce0181ee 100644
--- a/kernel/trace/Kconfig
+++ b/kernel/trace/Kconfig
@@ -27,9 +27,7 @@ config HAVE_FUNCTION_GRAPH_TRACER
config HAVE_FUNCTION_GRAPH_FP_TEST
bool
help
- An arch may pass in a unique value (frame pointer) to both the
- entering and exiting of a function. On exit, the value is compared
- and if it does not match, then it will panic the kernel.
+ See Documentation/trace/ftrace-design.txt
config HAVE_FUNCTION_TRACE_MCOUNT_TEST
bool
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index edefe3b2801b..8c1b2d290718 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -464,6 +464,8 @@ struct ring_buffer_iter {
struct ring_buffer_per_cpu *cpu_buffer;
unsigned long head;
struct buffer_page *head_page;
+ struct buffer_page *cache_reader_page;
+ unsigned long cache_read;
u64 read_stamp;
};
@@ -2716,6 +2718,8 @@ static void rb_iter_reset(struct ring_buffer_iter *iter)
iter->read_stamp = cpu_buffer->read_stamp;
else
iter->read_stamp = iter->head_page->page->time_stamp;
+ iter->cache_reader_page = cpu_buffer->reader_page;
+ iter->cache_read = cpu_buffer->read;
}
/**
@@ -3060,13 +3064,22 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
struct ring_buffer_event *event;
int nr_loops = 0;
- if (ring_buffer_iter_empty(iter))
- return NULL;
-
cpu_buffer = iter->cpu_buffer;
buffer = cpu_buffer->buffer;
+ /*
+ * Check if someone performed a consuming read to
+ * the buffer. A consuming read invalidates the iterator
+ * and we need to reset the iterator in this case.
+ */
+ if (unlikely(iter->cache_read != cpu_buffer->read ||
+ iter->cache_reader_page != cpu_buffer->reader_page))
+ rb_iter_reset(iter);
+
again:
+ if (ring_buffer_iter_empty(iter))
+ return NULL;
+
/*
* We repeat when a timestamp is encountered.
* We can get multiple timestamps by nested interrupts or also
@@ -3081,6 +3094,11 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts)
if (rb_per_cpu_empty(cpu_buffer))
return NULL;
+ if (iter->head >= local_read(&iter->head_page->page->commit)) {
+ rb_inc_iter(iter);
+ goto again;
+ }
+
event = rb_iter_head_event(iter);
switch (event->type_len) {
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 0df1b0f2cb9e..eac6875cb990 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -951,6 +951,11 @@ void trace_find_cmdline(int pid, char comm[])
return;
}
+ if (WARN_ON_ONCE(pid < 0)) {
+ strcpy(comm, "<XXX>");
+ return;
+ }
+
if (pid > PID_MAX_DEFAULT) {
strcpy(comm, "<...>");
return;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-18 02:16:34 +0000