Merge branch 'for-6.13-force-console' into for-linus (34767e53) · Commits · git / linux-nf

drivers/tty/sysrq.c

+8 −10

Original line number	Diff line number	Diff line
		@@ -582,7 +582,6 @@ static void __sysrq_put_key_op(u8 key, const struct sysrq_key_op *op_p)
		void __handle_sysrq(u8 key, bool check_mask)
		{
		const struct sysrq_key_op *op_p;
		int orig_log_level;
		int orig_suppress_printk;
		int i;

		@@ -592,13 +591,12 @@ void __handle_sysrq(u8 key, bool check_mask)
		rcu_sysrq_start();
		rcu_read_lock();
		/*
		* Raise the apparent loglevel to maximum so that the sysrq header
		* is shown to provide the user with positive feedback. We do not
		* simply emit this at KERN_EMERG as that would change message
		* routing in the consumers of /proc/kmsg.
		* Enter in the force_console context so that sysrq header is shown to
		* provide the user with positive feedback. We do not simply emit this
		* at KERN_EMERG as that would change message routing in the consumers
		* of /proc/kmsg.
		*/
		orig_log_level = console_loglevel;
		console_loglevel = CONSOLE_LOGLEVEL_DEFAULT;
		printk_force_console_enter();

		op_p = __sysrq_get_key_op(key);
		if (op_p) {
		@@ -608,11 +606,11 @@ void __handle_sysrq(u8 key, bool check_mask)
		*/
		if (!check_mask \|\| sysrq_on_mask(op_p->enable_mask)) {
		pr_info("%s\n", op_p->action_msg);
		console_loglevel = orig_log_level;
		printk_force_console_exit();
		op_p->handler(key);
		} else {
		pr_info("This sysrq operation is disabled.\n");
		console_loglevel = orig_log_level;
		printk_force_console_exit();
		}
		} else {
		pr_info("HELP : ");
		@@ -630,7 +628,7 @@ void __handle_sysrq(u8 key, bool check_mask)
		}
		}
		pr_cont("\n");
		console_loglevel = orig_log_level;
		printk_force_console_exit();
		}
		rcu_read_unlock();
		rcu_sysrq_end();

include/linux/printk.h

+11 −0

Original line number	Diff line number	Diff line
		@@ -166,6 +166,9 @@ __printf(1, 2) __cold int _printk_deferred(const char *fmt, ...);
		extern void __printk_deferred_enter(void);
		extern void __printk_deferred_exit(void);

		extern void printk_force_console_enter(void);
		extern void printk_force_console_exit(void);

		/*
		* The printk_deferred_enter/exit macros are available only as a hack for
		* some code paths that need to defer all printk console printing. Interrupts
		@@ -229,6 +232,14 @@ static inline void printk_deferred_exit(void)
		{
		}

		static inline void printk_force_console_enter(void)
		{
		}

		static inline void printk_force_console_exit(void)
		{
		}

		static inline int printk_ratelimit(void)
		{
		return 0;

kernel/printk/internal.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -53,6 +53,8 @@ int devkmsg_sysctl_set_loglvl(const struct ctl_table *table, int write,

		/* Flags for a single printk record. */
		enum printk_info_flags {
		/* always show on console, ignore console_loglevel */
		LOG_FORCE_CON = 1,
		LOG_NEWLINE = 2, /* text ended with a newline */
		LOG_CONT = 8, /* text is a fragment of a continuation line */
		};
		@@ -90,6 +92,7 @@ bool printk_percpu_data_ready(void);

		void defer_console_output(void);
		bool is_printk_legacy_deferred(void);
		bool is_printk_force_console(void);

		u16 printk_parse_prefix(const char text, int level,
		enum printk_info_flags *flags);

kernel/printk/printk.c

+16 −5

Original line number	Diff line number	Diff line
		@@ -1337,11 +1337,11 @@ static void boot_delay_msec(int level)
		{
		unsigned long long k;
		unsigned long timeout;
		bool suppress = !is_printk_force_console() &&
		suppress_message_printing(level);

		if ((boot_delay == 0 \|\| system_state >= SYSTEM_RUNNING)
		\|\| suppress_message_printing(level)) {
		if ((boot_delay == 0 \|\| system_state >= SYSTEM_RUNNING) \|\| suppress)
		return;
		}

		k = (unsigned long long)loops_per_msec * boot_delay;

		@@ -2291,6 +2291,9 @@ int vprintk_store(int facility, int level,
		if (dev_info)
		flags \|= LOG_NEWLINE;

		if (is_printk_force_console())
		flags \|= LOG_FORCE_CON;

		if (flags & LOG_CONT) {
		prb_rec_init_wr(&r, reserve_size);
		if (prb_reserve_in_last(&e, prb, &r, caller_id, PRINTKRB_RECORD_MAX)) {
		@@ -2298,6 +2301,9 @@ int vprintk_store(int facility, int level,
		facility, &flags, fmt, args);
		r.info->text_len += text_len;

		if (flags & LOG_FORCE_CON)
		r.info->flags \|= LOG_FORCE_CON;

		if (flags & LOG_NEWLINE) {
		r.info->flags \|= LOG_NEWLINE;
		prb_final_commit(&e);
		@@ -2965,6 +2971,7 @@ bool printk_get_next_message(struct printk_message *pmsg, u64 seq,
		struct printk_info info;
		struct printk_record r;
		size_t len = 0;
		bool force_con;

		/*
		* Formatting extended messages requires a separate buffer, so use the
		@@ -2983,9 +2990,13 @@ bool printk_get_next_message(struct printk_message *pmsg, u64 seq,

		pmsg->seq = r.info->seq;
		pmsg->dropped = r.info->seq - seq;
		force_con = r.info->flags & LOG_FORCE_CON;

		/* Skip record that has level above the console loglevel. */
		if (may_suppress && suppress_message_printing(r.info->level))
		/*
		* Skip records that are not forced to be printed on consoles and that
		* has level above the console loglevel.
		*/
		if (!force_con && may_suppress && suppress_message_printing(r.info->level))
		goto out;

		if (is_extended) {

kernel/printk/printk_safe.c

+18 −0

Original line number	Diff line number	Diff line
		@@ -12,6 +12,24 @@

		#include "internal.h"

		/* Context where printk messages are never suppressed */
		static atomic_t force_con;

		void printk_force_console_enter(void)
		{
		atomic_inc(&force_con);
		}

		void printk_force_console_exit(void)
		{
		atomic_dec(&force_con);
		}

		bool is_printk_force_console(void)
		{
		return atomic_read(&force_con);
		}

		static DEFINE_PER_CPU(int, printk_context);

		/* Can be preempted by NMI. */