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Diffstat (limited to 'kernel/printk/printk.c')
-rw-r--r--kernel/printk/printk.c124
1 files changed, 61 insertions, 63 deletions
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 8019cc0d3a73..d5e397315473 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -666,11 +666,8 @@ static ssize_t msg_print_ext_header(char *buf, size_t size,
* better readable output. 'c' in the record flags mark the first
* fragment of a line, '+' the following.
*/
- if (msg->flags & LOG_CONT && !(prev_flags & LOG_CONT))
- cont = 'c';
- else if ((msg->flags & LOG_CONT) ||
- ((prev_flags & LOG_CONT) && !(msg->flags & LOG_PREFIX)))
- cont = '+';
+ if (msg->flags & LOG_CONT)
+ cont = (prev_flags & LOG_CONT) ? '+' : 'c';
return scnprintf(buf, size, "%u,%llu,%llu,%c;",
(msg->facility << 3) | msg->level, seq, ts_usec, cont);
@@ -797,6 +794,8 @@ static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from)
return ret;
}
+static void cont_flush(void);
+
static ssize_t devkmsg_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
@@ -812,6 +811,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
if (ret)
return ret;
raw_spin_lock_irq(&logbuf_lock);
+ cont_flush();
while (user->seq == log_next_seq) {
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
@@ -874,6 +874,7 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
return -ESPIPE;
raw_spin_lock_irq(&logbuf_lock);
+ cont_flush();
switch (whence) {
case SEEK_SET:
/* the first record */
@@ -912,6 +913,7 @@ static unsigned int devkmsg_poll(struct file *file, poll_table *wait)
poll_wait(file, &log_wait, wait);
raw_spin_lock_irq(&logbuf_lock);
+ cont_flush();
if (user->seq < log_next_seq) {
/* return error when data has vanished underneath us */
if (user->seq < log_first_seq)
@@ -1298,6 +1300,7 @@ static int syslog_print(char __user *buf, int size)
size_t skip;
raw_spin_lock_irq(&logbuf_lock);
+ cont_flush();
if (syslog_seq < log_first_seq) {
/* messages are gone, move to first one */
syslog_seq = log_first_seq;
@@ -1357,6 +1360,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
return -ENOMEM;
raw_spin_lock_irq(&logbuf_lock);
+ cont_flush();
if (buf) {
u64 next_seq;
u64 seq;
@@ -1518,6 +1522,7 @@ int do_syslog(int type, char __user *buf, int len, int source)
/* Number of chars in the log buffer */
case SYSLOG_ACTION_SIZE_UNREAD:
raw_spin_lock_irq(&logbuf_lock);
+ cont_flush();
if (syslog_seq < log_first_seq) {
/* messages are gone, move to first one */
syslog_seq = log_first_seq;
@@ -1654,35 +1659,33 @@ static struct cont {
bool flushed:1; /* buffer sealed and committed */
} cont;
-static void cont_flush(enum log_flags flags)
+static void cont_flush(void)
{
if (cont.flushed)
return;
if (cont.len == 0)
return;
-
if (cont.cons) {
/*
* If a fragment of this line was directly flushed to the
* console; wait for the console to pick up the rest of the
* line. LOG_NOCONS suppresses a duplicated output.
*/
- log_store(cont.facility, cont.level, flags | LOG_NOCONS,
+ log_store(cont.facility, cont.level, cont.flags | LOG_NOCONS,
cont.ts_nsec, NULL, 0, cont.buf, cont.len);
- cont.flags = flags;
cont.flushed = true;
} else {
/*
* If no fragment of this line ever reached the console,
* just submit it to the store and free the buffer.
*/
- log_store(cont.facility, cont.level, flags, 0,
+ log_store(cont.facility, cont.level, cont.flags, 0,
NULL, 0, cont.buf, cont.len);
cont.len = 0;
}
}
-static bool cont_add(int facility, int level, const char *text, size_t len)
+static bool cont_add(int facility, int level, enum log_flags flags, const char *text, size_t len)
{
if (cont.len && cont.flushed)
return false;
@@ -1693,7 +1696,7 @@ static bool cont_add(int facility, int level, const char *text, size_t len)
* the line gets too long, split it up in separate records.
*/
if (nr_ext_console_drivers || cont.len + len > sizeof(cont.buf)) {
- cont_flush(LOG_CONT);
+ cont_flush();
return false;
}
@@ -1702,7 +1705,7 @@ static bool cont_add(int facility, int level, const char *text, size_t len)
cont.level = level;
cont.owner = current;
cont.ts_nsec = local_clock();
- cont.flags = 0;
+ cont.flags = flags;
cont.cons = 0;
cont.flushed = false;
}
@@ -1710,8 +1713,15 @@ static bool cont_add(int facility, int level, const char *text, size_t len)
memcpy(cont.buf + cont.len, text, len);
cont.len += len;
+ // The original flags come from the first line,
+ // but later continuations can add a newline.
+ if (flags & LOG_NEWLINE) {
+ cont.flags |= LOG_NEWLINE;
+ cont_flush();
+ }
+
if (cont.len > (sizeof(cont.buf) * 80) / 100)
- cont_flush(LOG_CONT);
+ cont_flush();
return true;
}
@@ -1744,6 +1754,31 @@ static size_t cont_print_text(char *text, size_t size)
return textlen;
}
+static size_t log_output(int facility, int level, enum log_flags lflags, const char *dict, size_t dictlen, char *text, size_t text_len)
+{
+ /*
+ * If an earlier line was buffered, and we're a continuation
+ * write from the same process, try to add it to the buffer.
+ */
+ if (cont.len) {
+ if (cont.owner == current && (lflags & LOG_CONT)) {
+ if (cont_add(facility, level, lflags, text, text_len))
+ return text_len;
+ }
+ /* Otherwise, make sure it's flushed */
+ cont_flush();
+ }
+
+ /* If it doesn't end in a newline, try to buffer the current line */
+ if (!(lflags & LOG_NEWLINE)) {
+ if (cont_add(facility, level, lflags, text, text_len))
+ return text_len;
+ }
+
+ /* Store it in the record log */
+ return log_store(facility, level, lflags, 0, dict, dictlen, text, text_len);
+}
+
asmlinkage int vprintk_emit(int facility, int level,
const char *dict, size_t dictlen,
const char *fmt, va_list args)
@@ -1830,10 +1865,9 @@ asmlinkage int vprintk_emit(int facility, int level,
/* strip kernel syslog prefix and extract log level or control flags */
if (facility == 0) {
- int kern_level = printk_get_level(text);
+ int kern_level;
- if (kern_level) {
- const char *end_of_header = printk_skip_level(text);
+ while ((kern_level = printk_get_level(text)) != 0) {
switch (kern_level) {
case '0' ... '7':
if (level == LOGLEVEL_DEFAULT)
@@ -1841,14 +1875,13 @@ asmlinkage int vprintk_emit(int facility, int level,
/* fallthrough */
case 'd': /* KERN_DEFAULT */
lflags |= LOG_PREFIX;
+ break;
+ case 'c': /* KERN_CONT */
+ lflags |= LOG_CONT;
}
- /*
- * No need to check length here because vscnprintf
- * put '\0' at the end of the string. Only valid and
- * newly printed level is detected.
- */
- text_len -= end_of_header - text;
- text = (char *)end_of_header;
+
+ text_len -= 2;
+ text += 2;
}
}
@@ -1858,45 +1891,7 @@ asmlinkage int vprintk_emit(int facility, int level,
if (dict)
lflags |= LOG_PREFIX|LOG_NEWLINE;
- if (!(lflags & LOG_NEWLINE)) {
- /*
- * Flush the conflicting buffer. An earlier newline was missing,
- * or another task also prints continuation lines.
- */
- if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))
- cont_flush(LOG_NEWLINE);
-
- /* buffer line if possible, otherwise store it right away */
- if (cont_add(facility, level, text, text_len))
- printed_len += text_len;
- else
- printed_len += log_store(facility, level,
- lflags | LOG_CONT, 0,
- dict, dictlen, text, text_len);
- } else {
- bool stored = false;
-
- /*
- * If an earlier newline was missing and it was the same task,
- * either merge it with the current buffer and flush, or if
- * there was a race with interrupts (prefix == true) then just
- * flush it out and store this line separately.
- * If the preceding printk was from a different task and missed
- * a newline, flush and append the newline.
- */
- if (cont.len) {
- if (cont.owner == current && !(lflags & LOG_PREFIX))
- stored = cont_add(facility, level, text,
- text_len);
- cont_flush(LOG_NEWLINE);
- }
-
- if (stored)
- printed_len += text_len;
- else
- printed_len += log_store(facility, level, lflags, 0,
- dict, dictlen, text, text_len);
- }
+ printed_len += log_output(facility, level, lflags, dict, dictlen, text, text_len);
logbuf_cpu = UINT_MAX;
raw_spin_unlock(&logbuf_lock);
@@ -3040,6 +3035,7 @@ void kmsg_dump(enum kmsg_dump_reason reason)
dumper->active = true;
raw_spin_lock_irqsave(&logbuf_lock, flags);
+ cont_flush();
dumper->cur_seq = clear_seq;
dumper->cur_idx = clear_idx;
dumper->next_seq = log_next_seq;
@@ -3130,6 +3126,7 @@ bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
bool ret;
raw_spin_lock_irqsave(&logbuf_lock, flags);
+ cont_flush();
ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
@@ -3172,6 +3169,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
goto out;
raw_spin_lock_irqsave(&logbuf_lock, flags);
+ cont_flush();
if (dumper->cur_seq < log_first_seq) {
/* messages are gone, move to first available one */
dumper->cur_seq = log_first_seq;