diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c index 14f8f00fdcf9..4a8405478ad8 100644 --- a/drivers/tty/sysrq.c +++ b/drivers/tty/sysrq.c @@ -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(); diff --git a/include/linux/printk.h b/include/linux/printk.h index eca9bb2ee637..4217a9f412b2 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -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; diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index 3fcb48502adb..c6bb47666aef 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -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); diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 968830cfc606..d27a64d58023 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -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) { diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c index 2b35a9d3919d..6f94418d53ff 100644 --- a/kernel/printk/printk_safe.c +++ b/kernel/printk/printk_safe.c @@ -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. */