If a log record has LOG_PREFIX set, its predecessor record should be
terminated if it was marked LOG_CONT.
In devkmsg_read(), this condition was being ignored, which would
lead to such records showing up combined when reading /dev/kmsg.
Fix this oversight.
We should similarly insert a newline in msg_print_text() in this
case, to avoid formatted records getting merged.
Suggested-by: Petr Mládek <pmla...@suse.cz>
Signed-off-by: Alex Elder <el...@linaro.org>
---
kernel/printk/printk.c | 18 +++++++++++++++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index e9f0632..a5ad81c 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -575,6 +575,7 @@ static ssize_t devkmsg_read(struct file *file, char __user
*buf,
char cont;
size_t len;
ssize_t ret;
+ bool insert_newline;
if (!user)
return -EBADF;
@@ -626,7 +627,10 @@ static ssize_t devkmsg_read(struct file *file, char __user
*buf,
else
cont = '-';
- len = sprintf(user->buf, "%u,%llu,%llu,%c;",
+ /* Insert a newline if the previous line was not terminated properly */
+ insert_newline = (user->prev & LOG_CONT) && (msg->flags & LOG_PREFIX);
+ len = sprintf(user->buf, "%s%u,%llu,%llu,%c;",
+ insert_newline ? "\n" : "",
(msg->facility << 3) | msg->level,
user->seq, ts_usec, cont);
user->prev = msg->flags;
@@ -999,10 +1003,12 @@ static size_t msg_print_text(const struct printk_log
*msg, enum log_flags prev,
{
const char *text = log_text(msg);
size_t text_size = msg->text_len;
+ size_t len = 0;
+ bool insert_newline;
bool prefix = true;
bool newline = true;
- size_t len = 0;
+ insert_newline = (prev & LOG_CONT) && (msg->flags & LOG_PREFIX);
if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))
prefix = false;
@@ -1023,9 +1029,13 @@ static size_t msg_print_text(const struct printk_log
*msg, enum log_flags prev,
if (buf) {
if (print_prefix(msg, syslog, NULL) +
- text_len + 1 >= size - len)
+ text_len + 2 >= size - len)
break;
+ if (insert_newline) {
+ insert_newline = false;
+ buf[len++] = '\n';
+ }
if (prefix)
len += print_prefix(msg, syslog, buf + len);
memcpy(buf + len, text, text_len);
@@ -1034,6 +1044,8 @@ static size_t msg_print_text(const struct printk_log
*msg, enum log_flags prev,
buf[len++] = '\n';
} else {
/* SYSLOG_ACTION_* buffer size only calculation */
+ if (insert_newline)
+ len++;
if (prefix)
len += print_prefix(msg, syslog, NULL);
len += text_len;
--
1.9.1
--
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