Update Linux to v5.4.148
Sourced from [1]
[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz
Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h
index c8e6ab6..b2b0f52 100644
--- a/kernel/printk/internal.h
+++ b/kernel/printk/internal.h
@@ -23,6 +23,9 @@
void __printk_safe_enter(void);
void __printk_safe_exit(void);
+void printk_safe_init(void);
+bool printk_percpu_data_ready(void);
+
#define printk_safe_enter_irqsave(flags) \
do { \
local_irq_save(flags); \
@@ -64,4 +67,6 @@
#define printk_safe_enter_irq() local_irq_disable()
#define printk_safe_exit_irq() local_irq_enable()
+static inline void printk_safe_init(void) { }
+static inline bool printk_percpu_data_ready(void) { return false; }
#endif /* CONFIG_PRINTK */
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index ca65327..5569ef6 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -460,6 +460,18 @@
static char *log_buf = __log_buf;
static u32 log_buf_len = __LOG_BUF_LEN;
+/*
+ * We cannot access per-CPU data (e.g. per-CPU flush irq_work) before
+ * per_cpu_areas are initialised. This variable is set to true when
+ * it's safe to access per-CPU data.
+ */
+static bool __printk_percpu_data_ready __read_mostly;
+
+bool printk_percpu_data_ready(void)
+{
+ return __printk_percpu_data_ready;
+}
+
/* Return log buffer address */
char *log_buf_addr_get(void)
{
@@ -1146,12 +1158,28 @@
static inline void log_buf_add_cpu(void) {}
#endif /* CONFIG_SMP */
+static void __init set_percpu_data_ready(void)
+{
+ printk_safe_init();
+ /* Make sure we set this flag only after printk_safe() init is done */
+ barrier();
+ __printk_percpu_data_ready = true;
+}
+
void __init setup_log_buf(int early)
{
unsigned long flags;
char *new_log_buf;
unsigned int free;
+ /*
+ * Some archs call setup_log_buf() multiple times - first is very
+ * early, e.g. from setup_arch(), and second - when percpu_areas
+ * are initialised.
+ */
+ if (!early)
+ set_percpu_data_ready();
+
if (log_buf != __log_buf)
return;
@@ -2165,6 +2193,9 @@
char *s, *options, *brl_options = NULL;
int idx;
+ if (str[0] == 0)
+ return 1;
+
if (_braille_console_setup(&str, &brl_options))
return 1;
@@ -2770,8 +2801,6 @@
* for us.
*/
logbuf_lock_irqsave(flags);
- console_seq = syslog_seq;
- console_idx = syslog_idx;
/*
* We're about to replay the log buffer. Only do this to the
* just-registered console to avoid excessive message spam to
@@ -2783,6 +2812,8 @@
*/
exclusive_console = newcon;
exclusive_console_stop_seq = console_seq;
+ console_seq = syslog_seq;
+ console_idx = syslog_idx;
logbuf_unlock_irqrestore(flags);
}
console_unlock();
@@ -2966,6 +2997,9 @@
void wake_up_klogd(void)
{
+ if (!printk_percpu_data_ready())
+ return;
+
preempt_disable();
if (waitqueue_active(&log_wait)) {
this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
@@ -2976,6 +3010,9 @@
void defer_console_output(void)
{
+ if (!printk_percpu_data_ready())
+ return;
+
preempt_disable();
__this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT);
irq_work_queue(this_cpu_ptr(&wake_up_klogd_work));
diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c
index b4045e7..6cfc5a0 100644
--- a/kernel/printk/printk_safe.c
+++ b/kernel/printk/printk_safe.c
@@ -27,7 +27,6 @@
* There are situations when we want to make sure that all buffers
* were handled or when IRQs are blocked.
*/
-static int printk_safe_irq_ready __read_mostly;
#define SAFE_LOG_BUF_LEN ((1 << CONFIG_PRINTK_SAFE_LOG_BUF_SHIFT) - \
sizeof(atomic_t) - \
@@ -44,6 +43,8 @@
static DEFINE_PER_CPU(struct printk_safe_seq_buf, safe_print_seq);
static DEFINE_PER_CPU(int, printk_context);
+static DEFINE_RAW_SPINLOCK(safe_read_lock);
+
#ifdef CONFIG_PRINTK_NMI
static DEFINE_PER_CPU(struct printk_safe_seq_buf, nmi_print_seq);
#endif
@@ -51,7 +52,7 @@
/* Get flushed in a more safe context. */
static void queue_flush_work(struct printk_safe_seq_buf *s)
{
- if (printk_safe_irq_ready)
+ if (printk_percpu_data_ready())
irq_work_queue(&s->work);
}
@@ -179,8 +180,6 @@
*/
static void __printk_safe_flush(struct irq_work *work)
{
- static raw_spinlock_t read_lock =
- __RAW_SPIN_LOCK_INITIALIZER(read_lock);
struct printk_safe_seq_buf *s =
container_of(work, struct printk_safe_seq_buf, work);
unsigned long flags;
@@ -194,7 +193,7 @@
* different CPUs. This is especially important when printing
* a backtrace.
*/
- raw_spin_lock_irqsave(&read_lock, flags);
+ raw_spin_lock_irqsave(&safe_read_lock, flags);
i = 0;
more:
@@ -231,7 +230,7 @@
out:
report_message_lost(s);
- raw_spin_unlock_irqrestore(&read_lock, flags);
+ raw_spin_unlock_irqrestore(&safe_read_lock, flags);
}
/**
@@ -277,6 +276,14 @@
raw_spin_lock_init(&logbuf_lock);
}
+ if (raw_spin_is_locked(&safe_read_lock)) {
+ if (num_online_cpus() > 1)
+ return;
+
+ debug_locks_off();
+ raw_spin_lock_init(&safe_read_lock);
+ }
+
printk_safe_flush();
}
@@ -402,14 +409,6 @@
#endif
}
- /*
- * In the highly unlikely event that a NMI were to trigger at
- * this moment. Make sure IRQ work is set up before this
- * variable is set.
- */
- barrier();
- printk_safe_irq_ready = 1;
-
/* Flush pending messages that did not have scheduled IRQ works. */
printk_safe_flush();
}