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Diffstat (limited to 'kernel/printk/nmi.c')
-rw-r--r--kernel/printk/nmi.c83
1 files changed, 53 insertions, 30 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