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-rw-r--r--drivers/tty/sysrq.c2
-rw-r--r--include/linux/printk.h11
-rw-r--r--kernel/hung_task.c11
-rw-r--r--kernel/panic.c4
-rw-r--r--kernel/printk/printk.c28
-rw-r--r--kernel/rcu/tree_stall.h2
-rw-r--r--kernel/reboot.c14
-rw-r--r--kernel/watchdog.c4
-rw-r--r--kernel/watchdog_hld.c4
9 files changed, 78 insertions, 2 deletions
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index bbfd004449b5..2884cd638d64 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -578,6 +578,7 @@ void __handle_sysrq(int key, bool check_mask)
rcu_sysrq_start();
rcu_read_lock();
+ printk_prefer_direct_enter();
/*
* Raise the apparent loglevel to maximum so that the sysrq header
* is shown to provide the user with positive feedback. We do not
@@ -619,6 +620,7 @@ void __handle_sysrq(int key, bool check_mask)
pr_cont("\n");
console_loglevel = orig_log_level;
}
+ printk_prefer_direct_exit();
rcu_read_unlock();
rcu_sysrq_end();
diff --git a/include/linux/printk.h b/include/linux/printk.h
index 091fba7283e1..cd26aab0ab2a 100644
--- a/include/linux/printk.h
+++ b/include/linux/printk.h
@@ -170,6 +170,9 @@ extern void __printk_safe_exit(void);
#define printk_deferred_enter __printk_safe_enter
#define printk_deferred_exit __printk_safe_exit
+extern void printk_prefer_direct_enter(void);
+extern void printk_prefer_direct_exit(void);
+
extern bool pr_flush(int timeout_ms, bool reset_on_progress);
/*
@@ -222,6 +225,14 @@ static inline void printk_deferred_exit(void)
{
}
+static inline void printk_prefer_direct_enter(void)
+{
+}
+
+static inline void printk_prefer_direct_exit(void)
+{
+}
+
static inline bool pr_flush(int timeout_ms, bool reset_on_progress)
{
return true;
diff --git a/kernel/hung_task.c b/kernel/hung_task.c
index 52501e5f7655..02a65d554340 100644
--- a/kernel/hung_task.c
+++ b/kernel/hung_task.c
@@ -127,6 +127,8 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
* complain:
*/
if (sysctl_hung_task_warnings) {
+ printk_prefer_direct_enter();
+
if (sysctl_hung_task_warnings > 0)
sysctl_hung_task_warnings--;
pr_err("INFO: task %s:%d blocked for more than %ld seconds.\n",
@@ -142,6 +144,8 @@ static void check_hung_task(struct task_struct *t, unsigned long timeout)
if (sysctl_hung_task_all_cpu_backtrace)
hung_task_show_all_bt = true;
+
+ printk_prefer_direct_exit();
}
touch_nmi_watchdog();
@@ -204,12 +208,17 @@ static void check_hung_uninterruptible_tasks(unsigned long timeout)
}
unlock:
rcu_read_unlock();
- if (hung_task_show_lock)
+ if (hung_task_show_lock) {
+ printk_prefer_direct_enter();
debug_show_all_locks();
+ printk_prefer_direct_exit();
+ }
if (hung_task_show_all_bt) {
hung_task_show_all_bt = false;
+ printk_prefer_direct_enter();
trigger_all_cpu_backtrace();
+ printk_prefer_direct_exit();
}
if (hung_task_call_panic)
diff --git a/kernel/panic.c b/kernel/panic.c
index 55b50e052ec3..7d422597403f 100644
--- a/kernel/panic.c
+++ b/kernel/panic.c
@@ -560,6 +560,8 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
{
disable_trace_on_warning();
+ printk_prefer_direct_enter();
+
if (file)
pr_warn("WARNING: CPU: %d PID: %d at %s:%d %pS\n",
raw_smp_processor_id(), current->pid, file, line,
@@ -597,6 +599,8 @@ void __warn(const char *file, int line, void *caller, unsigned taint,
/* Just a warning, don't kill lockdep. */
add_taint(taint, LOCKDEP_STILL_OK);
+
+ printk_prefer_direct_exit();
}
#ifndef __WARN_FLAGS
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index a06999d55278..ed7f738261cc 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -362,6 +362,34 @@ static int console_msg_format = MSG_FORMAT_DEFAULT;
static DEFINE_MUTEX(syslog_lock);
#ifdef CONFIG_PRINTK
+static atomic_t printk_prefer_direct = ATOMIC_INIT(0);
+
+/**
+ * printk_prefer_direct_enter - cause printk() calls to attempt direct
+ * printing to all enabled consoles
+ *
+ * Since it is not possible to call into the console printing code from any
+ * context, there is no guarantee that direct printing will occur.
+ *
+ * This globally effects all printk() callers.
+ *
+ * Context: Any context.
+ */
+void printk_prefer_direct_enter(void)
+{
+ atomic_inc(&printk_prefer_direct);
+}
+
+/**
+ * printk_prefer_direct_exit - restore printk() behavior
+ *
+ * Context: Any context.
+ */
+void printk_prefer_direct_exit(void)
+{
+ WARN_ON(atomic_dec_if_positive(&printk_prefer_direct) < 0);
+}
+
DECLARE_WAIT_QUEUE_HEAD(log_wait);
/* All 3 protected by @syslog_lock. */
/* the next printk record to read by syslog(READ) or /proc/kmsg */
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index 0c5d8516516a..d612707c2ed0 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -619,6 +619,7 @@ static void print_cpu_stall(unsigned long gps)
* See Documentation/RCU/stallwarn.rst for info on how to debug
* RCU CPU stall warnings.
*/
+ printk_prefer_direct_enter();
trace_rcu_stall_warning(rcu_state.name, TPS("SelfDetected"));
pr_err("INFO: %s self-detected stall on CPU\n", rcu_state.name);
raw_spin_lock_irqsave_rcu_node(rdp->mynode, flags);
@@ -656,6 +657,7 @@ static void print_cpu_stall(unsigned long gps)
*/
set_tsk_need_resched(current);
set_preempt_need_resched();
+ printk_prefer_direct_exit();
}
static void check_cpu_stall(struct rcu_data *rdp)
diff --git a/kernel/reboot.c b/kernel/reboot.c
index 6bcc5d6a6572..4177645e74d6 100644
--- a/kernel/reboot.c
+++ b/kernel/reboot.c
@@ -447,9 +447,11 @@ static int __orderly_reboot(void)
ret = run_cmd(reboot_cmd);
if (ret) {
+ printk_prefer_direct_enter();
pr_warn("Failed to start orderly reboot: forcing the issue\n");
emergency_sync();
kernel_restart(NULL);
+ printk_prefer_direct_exit();
}
return ret;
@@ -462,6 +464,7 @@ static int __orderly_poweroff(bool force)
ret = run_cmd(poweroff_cmd);
if (ret && force) {
+ printk_prefer_direct_enter();
pr_warn("Failed to start orderly shutdown: forcing the issue\n");
/*
@@ -471,6 +474,7 @@ static int __orderly_poweroff(bool force)
*/
emergency_sync();
kernel_power_off();
+ printk_prefer_direct_exit();
}
return ret;
@@ -528,6 +532,8 @@ EXPORT_SYMBOL_GPL(orderly_reboot);
*/
static void hw_failure_emergency_poweroff_func(struct work_struct *work)
{
+ printk_prefer_direct_enter();
+
/*
* We have reached here after the emergency shutdown waiting period has
* expired. This means orderly_poweroff has not been able to shut off
@@ -544,6 +550,8 @@ static void hw_failure_emergency_poweroff_func(struct work_struct *work)
*/
pr_emerg("Hardware protection shutdown failed. Trying emergency restart\n");
emergency_restart();
+
+ printk_prefer_direct_exit();
}
static DECLARE_DELAYED_WORK(hw_failure_emergency_poweroff_work,
@@ -582,11 +590,13 @@ void hw_protection_shutdown(const char *reason, int ms_until_forced)
{
static atomic_t allow_proceed = ATOMIC_INIT(1);
+ printk_prefer_direct_enter();
+
pr_emerg("HARDWARE PROTECTION shutdown (%s)\n", reason);
/* Shutdown should be initiated only once. */
if (!atomic_dec_and_test(&allow_proceed))
- return;
+ goto out;
/*
* Queue a backup emergency shutdown in the event of
@@ -594,6 +604,8 @@ void hw_protection_shutdown(const char *reason, int ms_until_forced)
*/
hw_failure_emergency_poweroff(ms_until_forced);
orderly_poweroff(true);
+out:
+ printk_prefer_direct_exit();
}
EXPORT_SYMBOL_GPL(hw_protection_shutdown);
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 9166220457bc..40024e03d422 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -424,6 +424,8 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
/* Start period for the next softlockup warning. */
update_report_ts();
+ printk_prefer_direct_enter();
+
pr_emerg("BUG: soft lockup - CPU#%d stuck for %us! [%s:%d]\n",
smp_processor_id(), duration,
current->comm, task_pid_nr(current));
@@ -442,6 +444,8 @@ static enum hrtimer_restart watchdog_timer_fn(struct hrtimer *hrtimer)
add_taint(TAINT_SOFTLOCKUP, LOCKDEP_STILL_OK);
if (softlockup_panic)
panic("softlockup: hung tasks");
+
+ printk_prefer_direct_exit();
}
return HRTIMER_RESTART;
diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c
index 247bf0b1582c..701f35f0e2d4 100644
--- a/kernel/watchdog_hld.c
+++ b/kernel/watchdog_hld.c
@@ -135,6 +135,8 @@ static void watchdog_overflow_callback(struct perf_event *event,
if (__this_cpu_read(hard_watchdog_warn) == true)
return;
+ printk_prefer_direct_enter();
+
pr_emerg("Watchdog detected hard LOCKUP on cpu %d\n",
this_cpu);
print_modules();
@@ -155,6 +157,8 @@ static void watchdog_overflow_callback(struct perf_event *event,
if (hardlockup_panic)
nmi_panic(regs, "Hard LOCKUP");
+ printk_prefer_direct_exit();
+
__this_cpu_write(hard_watchdog_warn, true);
return;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-21 16:06:09 +0000