diff options
Diffstat (limited to 'kernel/printk')
| -rw-r--r-- | kernel/printk/braille.c | 1 | ||||
| -rw-r--r-- | kernel/printk/braille.h | 1 | ||||
| -rw-r--r-- | kernel/printk/console_cmdline.h | 1 | ||||
| -rw-r--r-- | kernel/printk/internal.h | 6 | ||||
| -rw-r--r-- | kernel/printk/printk.c | 93 | ||||
| -rw-r--r-- | kernel/printk/printk_safe.c | 36 |
6 files changed, 84 insertions, 54 deletions
diff --git a/kernel/printk/braille.c b/kernel/printk/braille.c index 61d41ca41844..1d21ebacfdb8 100644 --- a/kernel/printk/braille.c +++ b/kernel/printk/braille.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/kernel.h> diff --git a/kernel/printk/braille.h b/kernel/printk/braille.h index 749a6756843a..123154f86304 100644 --- a/kernel/printk/braille.h +++ b/kernel/printk/braille.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _PRINTK_BRAILLE_H #define _PRINTK_BRAILLE_H diff --git a/kernel/printk/console_cmdline.h b/kernel/printk/console_cmdline.h index 2ca4a8b5fe57..11f19c466af5 100644 --- a/kernel/printk/console_cmdline.h +++ b/kernel/printk/console_cmdline.h @@ -1,3 +1,4 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _CONSOLE_CMDLINE_H #define _CONSOLE_CMDLINE_H diff --git a/kernel/printk/internal.h b/kernel/printk/internal.h index 1db044f808b7..2a7d04049af4 100644 --- a/kernel/printk/internal.h +++ b/kernel/printk/internal.h @@ -18,12 +18,14 @@ #ifdef CONFIG_PRINTK -#define PRINTK_SAFE_CONTEXT_MASK 0x7fffffff -#define PRINTK_NMI_CONTEXT_MASK 0x80000000 +#define PRINTK_SAFE_CONTEXT_MASK 0x3fffffff +#define PRINTK_NMI_DEFERRED_CONTEXT_MASK 0x40000000 +#define PRINTK_NMI_CONTEXT_MASK 0x80000000 extern raw_spinlock_t logbuf_lock; __printf(1, 0) int vprintk_default(const char *fmt, va_list args); +__printf(1, 0) int vprintk_deferred(const char *fmt, va_list args); __printf(1, 0) int vprintk_func(const char *fmt, va_list args); void __printk_safe_enter(void); void __printk_safe_exit(void); diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index a1db38abac5b..512f7c2baedd 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -649,7 +649,7 @@ static int syslog_action_restricted(int type) type != SYSLOG_ACTION_SIZE_BUFFER; } -int check_syslog_permissions(int type, int source) +static int check_syslog_permissions(int type, int source) { /* * If this is from /proc/kmsg and we've already opened it, then we've @@ -677,7 +677,6 @@ int check_syslog_permissions(int type, int source) ok: return security_syslog(type); } -EXPORT_SYMBOL_GPL(check_syslog_permissions); static void append_char(char **pp, char *e, char c) { @@ -1175,7 +1174,7 @@ static void boot_delay_msec(int level) unsigned long long k; unsigned long timeout; - if ((boot_delay == 0 || system_state != SYSTEM_BOOTING) + if ((boot_delay == 0 || system_state >= SYSTEM_RUNNING) || suppress_message_printing(level)) { return; } @@ -1435,7 +1434,7 @@ int do_syslog(int type, char __user *buf, int len, int source) error = check_syslog_permissions(type, source); if (error) - goto out; + return error; switch (type) { case SYSLOG_ACTION_CLOSE: /* Close log */ @@ -1443,20 +1442,16 @@ int do_syslog(int type, char __user *buf, int len, int source) case SYSLOG_ACTION_OPEN: /* Open log */ break; case SYSLOG_ACTION_READ: /* Read from log */ - error = -EINVAL; if (!buf || len < 0) - goto out; - error = 0; + return -EINVAL; if (!len) - goto out; - if (!access_ok(VERIFY_WRITE, buf, len)) { - error = -EFAULT; - goto out; - } + return 0; + if (!access_ok(VERIFY_WRITE, buf, len)) + return -EFAULT; error = wait_event_interruptible(log_wait, syslog_seq != log_next_seq); if (error) - goto out; + return error; error = syslog_print(buf, len); break; /* Read/clear last kernel messages */ @@ -1465,16 +1460,12 @@ int do_syslog(int type, char __user *buf, int len, int source) /* FALL THRU */ /* Read last kernel messages */ case SYSLOG_ACTION_READ_ALL: - error = -EINVAL; if (!buf || len < 0) - goto out; - error = 0; + return -EINVAL; if (!len) - goto out; - if (!access_ok(VERIFY_WRITE, buf, len)) { - error = -EFAULT; - goto out; - } + return 0; + if (!access_ok(VERIFY_WRITE, buf, len)) + return -EFAULT; error = syslog_print_all(buf, len, clear); break; /* Clear ring buffer */ @@ -1496,15 +1487,13 @@ int do_syslog(int type, char __user *buf, int len, int source) break; /* Set level of messages printed to console */ case SYSLOG_ACTION_CONSOLE_LEVEL: - error = -EINVAL; if (len < 1 || len > 8) - goto out; + return -EINVAL; if (len < minimum_console_loglevel) len = minimum_console_loglevel; console_loglevel = len; /* Implicitly re-enable logging to console */ saved_console_loglevel = LOGLEVEL_DEFAULT; - error = 0; break; /* Number of chars in the log buffer */ case SYSLOG_ACTION_SIZE_UNREAD: @@ -1526,7 +1515,6 @@ int do_syslog(int type, char __user *buf, int len, int source) u64 seq = syslog_seq; u32 idx = syslog_idx; - error = 0; while (seq < log_next_seq) { struct printk_log *msg = log_from_idx(idx); @@ -1546,7 +1534,7 @@ int do_syslog(int type, char __user *buf, int len, int source) error = -EINVAL; break; } -out: + return error; } @@ -1698,10 +1686,10 @@ asmlinkage int vprintk_emit(int facility, int level, { static char textbuf[LOG_LINE_MAX]; char *text = textbuf; - size_t text_len = 0; + size_t text_len; enum log_flags lflags = 0; unsigned long flags; - int printed_len = 0; + int printed_len; bool in_sched = false; if (level == LOGLEVEL_SCHED) { @@ -1754,7 +1742,7 @@ asmlinkage int vprintk_emit(int facility, int level, if (dict) lflags |= LOG_PREFIX|LOG_NEWLINE; - printed_len += log_output(facility, level, lflags, dict, dictlen, text, text_len); + printed_len = log_output(facility, level, lflags, dict, dictlen, text, text_len); logbuf_unlock_irqrestore(flags); @@ -2650,9 +2638,8 @@ void __init console_init(void) * makes it difficult to diagnose problems that occur during this time. * * To mitigate this problem somewhat, only unregister consoles whose memory - * intersects with the init section. Note that code exists elsewhere to get - * rid of the boot console as soon as the proper console shows up, so there - * won't be side-effects from postponing the removal. + * intersects with the init section. Note that all other boot consoles will + * get unregistred when the real preferred console is registered. */ static int __init printk_late_init(void) { @@ -2660,16 +2647,23 @@ static int __init printk_late_init(void) int ret; for_each_console(con) { - if (!keep_bootcon && con->flags & CON_BOOT) { + if (!(con->flags & CON_BOOT)) + continue; + + /* Check addresses that might be used for enabled consoles. */ + if (init_section_intersects(con, sizeof(*con)) || + init_section_contains(con->write, 0) || + init_section_contains(con->read, 0) || + init_section_contains(con->device, 0) || + init_section_contains(con->unblank, 0) || + init_section_contains(con->data, 0)) { /* - * Make sure to unregister boot consoles whose data - * resides in the init section before the init section - * is discarded. Boot consoles whose data will stick - * around will automatically be unregistered when the - * proper console replaces them. + * Please, consider moving the reported consoles out + * of the init section. */ - if (init_section_intersects(con, sizeof(*con))) - unregister_console(con); + pr_warn("bootconsole [%s%d] uses init memory and must be disabled even before the real one is ready\n", + con->name, con->index); + unregister_console(con); } } ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL, @@ -2720,16 +2714,13 @@ void wake_up_klogd(void) preempt_enable(); } -int printk_deferred(const char *fmt, ...) +int vprintk_deferred(const char *fmt, va_list args) { - va_list args; int r; - preempt_disable(); - va_start(args, fmt); r = vprintk_emit(0, LOGLEVEL_SCHED, NULL, 0, fmt, args); - va_end(args); + preempt_disable(); __this_cpu_or(printk_pending, PRINTK_PENDING_OUTPUT); irq_work_queue(this_cpu_ptr(&wake_up_klogd_work)); preempt_enable(); @@ -2737,6 +2728,18 @@ int printk_deferred(const char *fmt, ...) return r; } +int printk_deferred(const char *fmt, ...) +{ + va_list args; + int r; + + va_start(args, fmt); + r = vprintk_deferred(fmt, args); + va_end(args); + + return r; +} + /* * printk rate limiting, lifted from the networking subsystem. * diff --git a/kernel/printk/printk_safe.c b/kernel/printk/printk_safe.c index 033e50a7d706..3cdaeaef9ce1 100644 --- a/kernel/printk/printk_safe.c +++ b/kernel/printk/printk_safe.c @@ -80,8 +80,8 @@ static void queue_flush_work(struct printk_safe_seq_buf *s) * happen, printk_safe_log_store() will notice the buffer->len mismatch * and repeat the write. */ -static int printk_safe_log_store(struct printk_safe_seq_buf *s, - const char *fmt, va_list args) +static __printf(2, 0) int printk_safe_log_store(struct printk_safe_seq_buf *s, + const char *fmt, va_list args) { int add; size_t len; @@ -299,7 +299,7 @@ void printk_safe_flush_on_panic(void) * one writer running. But the buffer might get flushed from another * CPU, so we need to be careful. */ -static int vprintk_nmi(const char *fmt, va_list args) +static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args) { struct printk_safe_seq_buf *s = this_cpu_ptr(&nmi_print_seq); @@ -308,17 +308,29 @@ static int vprintk_nmi(const char *fmt, va_list args) void printk_nmi_enter(void) { - this_cpu_or(printk_context, PRINTK_NMI_CONTEXT_MASK); + /* + * The size of the extra per-CPU buffer is limited. Use it only when + * the main one is locked. If this CPU is not in the safe context, + * the lock must be taken on another CPU and we could wait for it. + */ + if ((this_cpu_read(printk_context) & PRINTK_SAFE_CONTEXT_MASK) && + raw_spin_is_locked(&logbuf_lock)) { + this_cpu_or(printk_context, PRINTK_NMI_CONTEXT_MASK); + } else { + this_cpu_or(printk_context, PRINTK_NMI_DEFERRED_CONTEXT_MASK); + } } void printk_nmi_exit(void) { - this_cpu_and(printk_context, ~PRINTK_NMI_CONTEXT_MASK); + this_cpu_and(printk_context, + ~(PRINTK_NMI_CONTEXT_MASK | + PRINTK_NMI_DEFERRED_CONTEXT_MASK)); } #else -static int vprintk_nmi(const char *fmt, va_list args) +static __printf(1, 0) int vprintk_nmi(const char *fmt, va_list args) { return 0; } @@ -330,7 +342,7 @@ static int vprintk_nmi(const char *fmt, va_list args) * into itself. It uses a per-CPU buffer to store the message, just like * NMI. */ -static int vprintk_safe(const char *fmt, va_list args) +static __printf(1, 0) int vprintk_safe(const char *fmt, va_list args) { struct printk_safe_seq_buf *s = this_cpu_ptr(&safe_print_seq); @@ -351,12 +363,22 @@ void __printk_safe_exit(void) __printf(1, 0) int vprintk_func(const char *fmt, va_list args) { + /* Use extra buffer in NMI when logbuf_lock is taken or in safe mode. */ if (this_cpu_read(printk_context) & PRINTK_NMI_CONTEXT_MASK) return vprintk_nmi(fmt, args); + /* Use extra buffer to prevent a recursion deadlock in safe mode. */ if (this_cpu_read(printk_context) & PRINTK_SAFE_CONTEXT_MASK) return vprintk_safe(fmt, args); + /* + * Use the main logbuf when logbuf_lock is available in NMI. + * But avoid calling console drivers that might have their own locks. + */ + if (this_cpu_read(printk_context) & PRINTK_NMI_DEFERRED_CONTEXT_MASK) + return vprintk_deferred(fmt, args); + + /* No obstacles. */ return vprintk_default(fmt, args); } |