diff options
Diffstat (limited to 'kernel/printk')
| -rw-r--r-- | kernel/printk/nmi.c | 83 | ||||
| -rw-r--r-- | kernel/printk/printk.c | 25 |
2 files changed, 65 insertions, 43 deletions
diff --git a/kernel/printk/nmi.c b/kernel/printk/nmi.c index 16bab471c7e2..f011aaef583c 100644 --- a/kernel/printk/nmi.c +++ b/kernel/printk/nmi.c @@ -67,7 +67,8 @@ static int vprintk_nmi(const char *fmt, va_list args) again: len = atomic_read(&s->len); - if (len >= sizeof(s->buffer)) { + /* The trailing '\0' is not counted into len. */ + if (len >= sizeof(s->buffer) - 1) { atomic_inc(&nmi_message_lost); return 0; } @@ -79,7 +80,7 @@ again: if (!len) smp_rmb(); - add = vsnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, args); + add = vscnprintf(s->buffer + len, sizeof(s->buffer) - len, fmt, args); /* * Do it once again if the buffer has been flushed in the meantime. @@ -113,16 +114,51 @@ static void printk_nmi_flush_line(const char *text, int len) } -/* - * printk one line from the temporary buffer from @start index until - * and including the @end index. - */ -static void printk_nmi_flush_seq_line(struct nmi_seq_buf *s, - int start, int end) +/* printk part of the temporary buffer line by line */ +static int printk_nmi_flush_buffer(const char *start, size_t len) { - const char *buf = s->buffer + start; + const char *c, *end; + bool header; + + c = start; + end = start + len; + header = true; + + /* Print line by line. */ + while (c < end) { + if (*c == '\n') { + printk_nmi_flush_line(start, c - start + 1); + start = ++c; + header = true; + continue; + } + + /* Handle continuous lines or missing new line. */ + if ((c + 1 < end) && printk_get_level(c)) { + if (header) { + c = printk_skip_level(c); + continue; + } + + printk_nmi_flush_line(start, c - start); + start = c++; + header = true; + continue; + } + + header = false; + c++; + } - printk_nmi_flush_line(buf, (end - start) + 1); + /* Check if there was a partial line. Ignore pure header. */ + if (start < end && !header) { + static const char newline[] = KERN_CONT "\n"; + + printk_nmi_flush_line(start, end - start); + printk_nmi_flush_line(newline, strlen(newline)); + } + + return len; } /* @@ -135,8 +171,8 @@ static void __printk_nmi_flush(struct irq_work *work) __RAW_SPIN_LOCK_INITIALIZER(read_lock); struct nmi_seq_buf *s = container_of(work, struct nmi_seq_buf, work); unsigned long flags; - size_t len, size; - int i, last_i; + size_t len; + int i; /* * The lock has two functions. First, one reader has to flush all @@ -154,12 +190,14 @@ more: /* * This is just a paranoid check that nobody has manipulated * the buffer an unexpected way. If we printed something then - * @len must only increase. + * @len must only increase. Also it should never overflow the + * buffer size. */ - if (i && i >= len) { + if ((i && i >= len) || len > sizeof(s->buffer)) { const char *msg = "printk_nmi_flush: internal error\n"; printk_nmi_flush_line(msg, strlen(msg)); + len = 0; } if (!len) @@ -167,22 +205,7 @@ more: /* Make sure that data has been written up to the @len */ smp_rmb(); - - size = min(len, sizeof(s->buffer)); - last_i = i; - - /* Print line by line. */ - for (; i < size; i++) { - if (s->buffer[i] == '\n') { - printk_nmi_flush_seq_line(s, last_i, i); - last_i = i + 1; - } - } - /* Check if there was a partial line. */ - if (last_i < size) { - printk_nmi_flush_seq_line(s, last_i, size - 1); - printk_nmi_flush_line("\n", strlen("\n")); - } + i += printk_nmi_flush_buffer(s->buffer + i, len - i); /* * Check that nothing has got added in the meantime and truncate diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index f7a55e9ff2f7..577f2288d19f 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -2166,27 +2166,20 @@ void resume_console(void) /** * console_cpu_notify - print deferred console messages after CPU hotplug - * @self: notifier struct - * @action: CPU hotplug event - * @hcpu: unused + * @cpu: unused * * If printk() is called from a CPU that is not online yet, the messages * will be spooled but will not show up on the console. This function is * called when a new CPU comes online (or fails to come up), and ensures * that any such output gets printed. */ -static int console_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) -{ - switch (action) { - case CPU_ONLINE: - case CPU_DEAD: - case CPU_DOWN_FAILED: - case CPU_UP_CANCELED: +static int console_cpu_notify(unsigned int cpu) +{ + if (!cpuhp_tasks_frozen) { console_lock(); console_unlock(); } - return NOTIFY_OK; + return 0; } /** @@ -2824,6 +2817,7 @@ EXPORT_SYMBOL(unregister_console); static int __init printk_late_init(void) { struct console *con; + int ret; for_each_console(con) { if (!keep_bootcon && con->flags & CON_BOOT) { @@ -2838,7 +2832,12 @@ static int __init printk_late_init(void) unregister_console(con); } } - hotcpu_notifier(console_cpu_notify, 0); + ret = cpuhp_setup_state_nocalls(CPUHP_PRINTK_DEAD, "printk:dead", NULL, + console_cpu_notify); + WARN_ON(ret < 0); + ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN, "printk:online", + console_cpu_notify, NULL); + WARN_ON(ret < 0); return 0; } late_initcall(printk_late_init); |
