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Diffstat (limited to 'kernel/printk.c')
-rw-r--r--kernel/printk.c84
1 files changed, 54 insertions, 30 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index b1d5a6174d65..baf2aebd6970 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -100,7 +100,7 @@ static int console_locked, console_suspended;
* It is also used in interesting ways to provide interlocking in
* console_unlock();.
*/
-static DEFINE_SPINLOCK(logbuf_lock);
+static DEFINE_RAW_SPINLOCK(logbuf_lock);
#define LOG_BUF_MASK (log_buf_len-1)
#define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK])
@@ -212,7 +212,7 @@ void __init setup_log_buf(int early)
return;
}
- spin_lock_irqsave(&logbuf_lock, flags);
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
log_buf_len = new_log_buf_len;
log_buf = new_log_buf;
new_log_buf_len = 0;
@@ -230,7 +230,7 @@ void __init setup_log_buf(int early)
log_start -= offset;
con_start -= offset;
log_end -= offset;
- spin_unlock_irqrestore(&logbuf_lock, flags);
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
pr_info("log_buf_len: %d\n", log_buf_len);
pr_info("early log buf free: %d(%d%%)\n",
@@ -318,8 +318,10 @@ static int check_syslog_permissions(int type, bool from_file)
return 0;
/* For historical reasons, accept CAP_SYS_ADMIN too, with a warning */
if (capable(CAP_SYS_ADMIN)) {
- WARN_ONCE(1, "Attempt to access syslog with CAP_SYS_ADMIN "
- "but no CAP_SYSLOG (deprecated).\n");
+ printk_once(KERN_WARNING "%s (%d): "
+ "Attempt to access syslog with CAP_SYS_ADMIN "
+ "but no CAP_SYSLOG (deprecated).\n",
+ current->comm, task_pid_nr(current));
return 0;
}
return -EPERM;
@@ -363,18 +365,18 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
if (error)
goto out;
i = 0;
- spin_lock_irq(&logbuf_lock);
+ raw_spin_lock_irq(&logbuf_lock);
while (!error && (log_start != log_end) && i < len) {
c = LOG_BUF(log_start);
log_start++;
- spin_unlock_irq(&logbuf_lock);
+ raw_spin_unlock_irq(&logbuf_lock);
error = __put_user(c,buf);
buf++;
i++;
cond_resched();
- spin_lock_irq(&logbuf_lock);
+ raw_spin_lock_irq(&logbuf_lock);
}
- spin_unlock_irq(&logbuf_lock);
+ raw_spin_unlock_irq(&logbuf_lock);
if (!error)
error = i;
break;
@@ -397,7 +399,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
count = len;
if (count > log_buf_len)
count = log_buf_len;
- spin_lock_irq(&logbuf_lock);
+ raw_spin_lock_irq(&logbuf_lock);
if (count > logged_chars)
count = logged_chars;
if (do_clear)
@@ -414,12 +416,12 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
if (j + log_buf_len < log_end)
break;
c = LOG_BUF(j);
- spin_unlock_irq(&logbuf_lock);
+ raw_spin_unlock_irq(&logbuf_lock);
error = __put_user(c,&buf[count-1-i]);
cond_resched();
- spin_lock_irq(&logbuf_lock);
+ raw_spin_lock_irq(&logbuf_lock);
}
- spin_unlock_irq(&logbuf_lock);
+ raw_spin_unlock_irq(&logbuf_lock);
if (error)
break;
error = i;
@@ -530,6 +532,9 @@ static int __init ignore_loglevel_setup(char *str)
}
early_param("ignore_loglevel", ignore_loglevel_setup);
+module_param_named(ignore_loglevel, ignore_loglevel, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
+ "print all kernel messages to the console.");
/*
* Write out chars from start to end - 1 inclusive
@@ -590,9 +595,6 @@ static size_t log_prefix(const char *p, unsigned int *level, char *special)
/* multi digit including the level and facility number */
char *endp = NULL;
- if (p[1] < '0' && p[1] > '9')
- return 0;
-
lev = (simple_strtoul(&p[1], &endp, 10) & 7);
if (endp == NULL || endp[0] != '>')
return 0;
@@ -687,7 +689,7 @@ static void zap_locks(void)
oops_timestamp = jiffies;
/* If a crash is occurring, make sure we can't deadlock */
- spin_lock_init(&logbuf_lock);
+ raw_spin_lock_init(&logbuf_lock);
/* And make sure that we print immediately */
sema_init(&console_sem, 1);
}
@@ -782,7 +784,7 @@ static inline int can_use_console(unsigned int cpu)
static int console_trylock_for_printk(unsigned int cpu)
__releases(&logbuf_lock)
{
- int retval = 0;
+ int retval = 0, wake = 0;
if (console_trylock()) {
retval = 1;
@@ -795,12 +797,14 @@ static int console_trylock_for_printk(unsigned int cpu)
*/
if (!can_use_console(cpu)) {
console_locked = 0;
- up(&console_sem);
+ wake = 1;
retval = 0;
}
}
printk_cpu = UINT_MAX;
- spin_unlock(&logbuf_lock);
+ if (wake)
+ up(&console_sem);
+ raw_spin_unlock(&logbuf_lock);
return retval;
}
static const char recursion_bug_msg [] =
@@ -860,7 +864,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
}
lockdep_off();
- spin_lock(&logbuf_lock);
+ raw_spin_lock(&logbuf_lock);
printk_cpu = this_cpu;
if (recursion_bug) {
@@ -1104,6 +1108,10 @@ static int __init console_suspend_disable(char *str)
return 1;
}
__setup("no_console_suspend", console_suspend_disable);
+module_param_named(console_suspend, console_suspend_enabled,
+ bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(console_suspend, "suspend console during suspend"
+ " and hibernate operations");
/**
* suspend_console - suspend the console subsystem
@@ -1242,7 +1250,7 @@ void console_unlock(void)
{
unsigned long flags;
unsigned _con_start, _log_end;
- unsigned wake_klogd = 0;
+ unsigned wake_klogd = 0, retry = 0;
if (console_suspended) {
up(&console_sem);
@@ -1251,15 +1259,16 @@ void console_unlock(void)
console_may_schedule = 0;
+again:
for ( ; ; ) {
- spin_lock_irqsave(&logbuf_lock, flags);
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
wake_klogd |= log_start - log_end;
if (con_start == log_end)
break; /* Nothing to print */
_con_start = con_start;
_log_end = log_end;
con_start = log_end; /* Flush */
- spin_unlock(&logbuf_lock);
+ raw_spin_unlock(&logbuf_lock);
stop_critical_timings(); /* don't trace print latency */
call_console_drivers(_con_start, _log_end);
start_critical_timings();
@@ -1271,8 +1280,23 @@ void console_unlock(void)
if (unlikely(exclusive_console))
exclusive_console = NULL;
+ raw_spin_unlock(&logbuf_lock);
+
up(&console_sem);
- spin_unlock_irqrestore(&logbuf_lock, flags);
+
+ /*
+ * Someone could have filled up the buffer again, so re-check if there's
+ * something to flush. In case we cannot trylock the console_sem again,
+ * there's a new owner and the console_unlock() from them will do the
+ * flush, no worries.
+ */
+ raw_spin_lock(&logbuf_lock);
+ if (con_start != log_end)
+ retry = 1;
+ if (retry && console_trylock())
+ goto again;
+
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
if (wake_klogd)
wake_up_klogd();
}
@@ -1502,9 +1526,9 @@ void register_console(struct console *newcon)
* console_unlock(); will print out the buffered messages
* for us.
*/
- spin_lock_irqsave(&logbuf_lock, flags);
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
con_start = log_start;
- spin_unlock_irqrestore(&logbuf_lock, flags);
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
/*
* We're about to replay the log buffer. Only do this to the
* just-registered console to avoid excessive message spam to
@@ -1584,7 +1608,7 @@ static int __init printk_late_init(void)
struct console *con;
for_each_console(con) {
- if (con->flags & CON_BOOT) {
+ if (!keep_bootcon && con->flags & CON_BOOT) {
printk(KERN_INFO "turn off boot console %s%d\n",
con->name, con->index);
unregister_console(con);
@@ -1711,10 +1735,10 @@ void kmsg_dump(enum kmsg_dump_reason reason)
/* Theoretically, the log could move on after we do this, but
there's not a lot we can do about that. The new messages
will overwrite the start of what we dump. */
- spin_lock_irqsave(&logbuf_lock, flags);
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
end = log_end & LOG_BUF_MASK;
chars = logged_chars;
- spin_unlock_irqrestore(&logbuf_lock, flags);
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
if (chars > end) {
s1 = log_buf + log_buf_len - chars + end;
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-23 01:25:33 +0000