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Commit 70498253 authored by Kay Sievers's avatar Kay Sievers Committed by Greg Kroah-Hartman
Browse files

kmsg - properly print over-long continuation lines 



Reserve PREFIX_MAX bytes in the LOG_LINE_MAX line when buffering a
continuation line, to be able to properly prefix the LOG_LINE_MAX
line with the syslog prefix and timestamp when printing it.

Reported-By: default avatarDave Jones <davej@redhat.com>
Signed-off-by: default avatarKay Sievers <kay@vrfy.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 28a78e46

kernel/printk.c

+19 −14
Original line number Diff line number Diff line
@@ -235,7 +235,8 @@ static u32 log_next_idx; 
static u64 clear_seq;

static u32 clear_idx;



#define LOG_LINE_MAX 1024

#define PREFIX_MAX		32

#define LOG_LINE_MAX		1024 - PREFIX_MAX



/* record buffer */

#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
@@ -907,7 +908,7 @@ static int syslog_print(char __user *buf, int size) 
	struct log *msg;

	int len = 0;



	text = kmalloc(LOG_LINE_MAX, GFP_KERNEL);

	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);

	if (!text)

		return -ENOMEM;
@@ -930,7 +931,8 @@ static int syslog_print(char __user *buf, int size) 


		skip = syslog_partial;

		msg = log_from_idx(syslog_idx);

		n = msg_print_text(msg, syslog_prev, true, text, LOG_LINE_MAX);

		n = msg_print_text(msg, syslog_prev, true, text,

				   LOG_LINE_MAX + PREFIX_MAX);

		if (n - syslog_partial <= size) {

			/* message fits into buffer, move forward */

			syslog_idx = log_next(syslog_idx);
@@ -969,7 +971,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear) 
	char *text;

	int len = 0;



	text = kmalloc(LOG_LINE_MAX, GFP_KERNEL);

	text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);

	if (!text)

		return -ENOMEM;
@@ -1022,7 +1024,8 @@ static int syslog_print_all(char __user *buf, int size, bool clear) 
			struct log *msg = log_from_idx(idx);

			int textlen;



			textlen = msg_print_text(msg, prev, true, text, LOG_LINE_MAX);

			textlen = msg_print_text(msg, prev, true, text,

						 LOG_LINE_MAX + PREFIX_MAX);

			if (textlen < 0) {

				len = textlen;

				break;
@@ -1367,15 +1370,15 @@ static struct cont { 
	bool flushed:1;			/* buffer sealed and committed */

} cont;



static void cont_flush(void)

static void cont_flush(enum log_flags flags)

{

	if (cont.flushed)

		return;

	if (cont.len == 0)

		return;



	log_store(cont.facility, cont.level, LOG_NOCONS, cont.ts_nsec,

		  NULL, 0, cont.buf, cont.len);

	log_store(cont.facility, cont.level, LOG_NOCONS | flags,

		  cont.ts_nsec, NULL, 0, cont.buf, cont.len);



	cont.flushed = true;

}
@@ -1386,7 +1389,8 @@ static bool cont_add(int facility, int level, const char *text, size_t len) 
		return false;



	if (cont.len + len > sizeof(cont.buf)) {

		cont_flush();

		/* the line gets too long, split it up in separate records */

		cont_flush(LOG_CONT);

		return false;

	}
@@ -1522,7 +1526,7 @@ asmlinkage int vprintk_emit(int facility, int level, 
		 * or another task also prints continuation lines.

		 */

		if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))

			cont_flush();

			cont_flush(0);



		/* buffer line if possible, otherwise store it right away */

		if (!cont_add(facility, level, text, text_len))
@@ -1540,7 +1544,7 @@ asmlinkage int vprintk_emit(int facility, int level, 
		if (cont.len && cont.owner == current) {

			if (!(lflags & LOG_PREFIX))

				stored = cont_add(facility, level, text, text_len);

			cont_flush();

			cont_flush(0);

		}



		if (!stored)
@@ -1634,6 +1638,7 @@ EXPORT_SYMBOL(printk); 
#else



#define LOG_LINE_MAX		0

#define PREFIX_MAX		0

static struct cont {

	size_t len;

	size_t cons;
@@ -1938,7 +1943,7 @@ static enum log_flags console_prev; 
 */

void console_unlock(void)

{

	static char text[LOG_LINE_MAX];

	static char text[LOG_LINE_MAX + PREFIX_MAX];

	static u64 seen_seq;

	unsigned long flags;

	bool wake_klogd = false;