diff options
Diffstat (limited to 'kernel/printk/printk.c')
| -rw-r--r-- | kernel/printk/printk.c | 67 |
1 files changed, 48 insertions, 19 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 2984fb0f0257..a1db38abac5b 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -32,7 +32,7 @@ #include <linux/bootmem.h> #include <linux/memblock.h> #include <linux/syscalls.h> -#include <linux/kexec.h> +#include <linux/crash_core.h> #include <linux/kdb.h> #include <linux/ratelimit.h> #include <linux/kmsg_dump.h> @@ -270,7 +270,6 @@ static struct console *exclusive_console; static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; -static int selected_console = -1; static int preferred_console = -1; int console_set_on_cmdline; EXPORT_SYMBOL(console_set_on_cmdline); @@ -1002,7 +1001,7 @@ const struct file_operations kmsg_fops = { .release = devkmsg_release, }; -#ifdef CONFIG_KEXEC_CORE +#ifdef CONFIG_CRASH_CORE /* * This appends the listed symbols to /proc/vmcore * @@ -1011,7 +1010,7 @@ const struct file_operations kmsg_fops = { * symbols are specifically used so that utilities can access and extract the * dmesg log from a vmcore file after a crash. */ -void log_buf_kexec_setup(void) +void log_buf_vmcoreinfo_setup(void) { VMCOREINFO_SYMBOL(log_buf); VMCOREINFO_SYMBOL(log_buf_len); @@ -1911,14 +1910,14 @@ static int __add_preferred_console(char *name, int idx, char *options, i++, c++) { if (strcmp(c->name, name) == 0 && c->index == idx) { if (!brl_options) - selected_console = i; + preferred_console = i; return 0; } } if (i == MAX_CMDLINECONSOLES) return -E2BIG; if (!brl_options) - selected_console = i; + preferred_console = i; strlcpy(c->name, name, sizeof(c->name)); c->options = options; braille_set_options(c, brl_options); @@ -2031,15 +2030,16 @@ void resume_console(void) * @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. + * will be printed on the console only if there are CON_ANYTIME consoles. + * This function is called when a new CPU comes online (or fails to come + * up) or goes offline. */ static int console_cpu_notify(unsigned int cpu) { if (!cpuhp_tasks_frozen) { - console_lock(); - console_unlock(); + /* If trylock fails, someone else is doing the printing */ + if (console_trylock()) + console_unlock(); } return 0; } @@ -2161,7 +2161,7 @@ void console_unlock(void) } /* - * Console drivers are called under logbuf_lock, so + * Console drivers are called with interrupts disabled, so * @console_may_schedule should be cleared before; however, we may * end up dumping a lot of lines, for example, if called from * console registration path, and should invoke cond_resched() @@ -2169,11 +2169,15 @@ void console_unlock(void) * scheduling stall on a slow console leading to RCU stall and * softlockup warnings which exacerbate the issue with more * messages practically incapacitating the system. + * + * console_trylock() is not able to detect the preemptive + * context reliably. Therefore the value must be stored before + * and cleared after the the "again" goto label. */ do_cond_resched = console_may_schedule; +again: console_may_schedule = 0; -again: /* * We released the console_sem lock, so we need to recheck if * cpu is online and (if not) is there at least one CON_ANYTIME @@ -2409,6 +2413,7 @@ void register_console(struct console *newcon) unsigned long flags; struct console *bcon = NULL; struct console_cmdline *c; + static bool has_preferred; if (console_drivers) for_each_console(bcon) @@ -2435,15 +2440,15 @@ void register_console(struct console *newcon) if (console_drivers && console_drivers->flags & CON_BOOT) bcon = console_drivers; - if (preferred_console < 0 || bcon || !console_drivers) - preferred_console = selected_console; + if (!has_preferred || bcon || !console_drivers) + has_preferred = preferred_console >= 0; /* * See if we want to use this console driver. If we * didn't select a console we take the first one * that registers here. */ - if (preferred_console < 0) { + if (!has_preferred) { if (newcon->index < 0) newcon->index = 0; if (newcon->setup == NULL || @@ -2451,7 +2456,7 @@ void register_console(struct console *newcon) newcon->flags |= CON_ENABLED; if (newcon->device) { newcon->flags |= CON_CONSDEV; - preferred_console = 0; + has_preferred = true; } } } @@ -2484,9 +2489,9 @@ void register_console(struct console *newcon) } newcon->flags |= CON_ENABLED; - if (i == selected_console) { + if (i == preferred_console) { newcon->flags |= CON_CONSDEV; - preferred_console = selected_console; + has_preferred = true; } break; } @@ -2611,6 +2616,30 @@ int unregister_console(struct console *console) EXPORT_SYMBOL(unregister_console); /* + * Initialize the console device. This is called *early*, so + * we can't necessarily depend on lots of kernel help here. + * Just do some early initializations, and do the complex setup + * later. + */ +void __init console_init(void) +{ + initcall_t *call; + + /* Setup the default TTY line discipline. */ + n_tty_init(); + + /* + * set up the console device so that later boot sequences can + * inform about problems etc.. + */ + call = __con_initcall_start; + while (call < __con_initcall_end) { + (*call)(); + call++; + } +} + +/* * Some boot consoles access data that is in the init section and which will * be discarded after the initcalls have been run. To make sure that no code * will access this data, unregister the boot consoles in a late initcall. |