printk: fix log_next()

1 files changed, 45 insertions, 35 deletions

diff --git a/printk.patch b/printk.patch
index 3bc374c..09870ce 100644
--- a/printk.patch
+++ b/printk.patch
@@ -100,15 +100,15 @@ devices, drivers, subsystems, classes and types of messages.
   SYSLOG_FACILITY=3
   PRIORITY=6
   SEQNUM=863
-  TIMESTAMP=3679024
-  MESSAGE=udevd[83]: starting version 175
+  TIMESTAMP=2479024
+  MESSAGE=udevd[71]: starting version 182
 
   ...
 
   PRIORITY=6
   SEQNUM=1012
-  TIMESTAMP=7169447
-  MESSAGE=usb 2-1.4: MAC-Address: 02:80:37:ec:02:00
+  TIMESTAMP=4069447
+  MESSAGE=usb 2-1.4: MAC-Address: 02:80:37:e6:12:00
   SUBSYSTEM=usb
   DEVICE=c189:130
 
@@ -117,8 +117,8 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  drivers/base/core.c    |   49 +
  drivers/char/mem.c     |   40 -
  include/linux/printk.h |   13 
- kernel/printk.c        | 1384 +++++++++++++++++++++++++++++++++----------------
- 4 files changed, 1017 insertions(+), 469 deletions(-)
+ kernel/printk.c        | 1394 +++++++++++++++++++++++++++++++++----------------
+ 4 files changed, 1027 insertions(+), 469 deletions(-)
 
 --- a/drivers/base/core.c
 +++ b/drivers/base/core.c
@@ -322,7 +322,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
   * If exclusive_console is non-NULL then only this console is to be printed to.
   */
  static struct console *exclusive_console;
-@@ -146,12 +127,539 @@ EXPORT_SYMBOL(console_set_on_cmdline);
+@@ -146,12 +127,549 @@ EXPORT_SYMBOL(console_set_on_cmdline);
  static int console_may_schedule;
  
  #ifdef CONFIG_PRINTK
@@ -482,7 +482,10 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
 +{
 +	struct log *msg = (struct log *)(log_buf + idx);
 +
-+	/* length == 0 indicates the end of the buffer; wrap */
++	/*
++	 * A length == 0 record is the end of buffer marker. Wrap around and
++	 * read the message at the start of the buffer.
++	 */
 +	if (!msg->len)
 +		return (struct log *)log_buf;
 +	return msg;
@@ -494,8 +497,15 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
 +	struct log *msg = (struct log *)(log_buf + idx);
 +
 +	/* length == 0 indicates the end of the buffer; wrap */
-+	if (!msg->len)
-+		return 0;
++	/*
++	 * A length == 0 record is the end of buffer marker. Wrap around and
++	 * read the message at the start of the buffer as *this* one, and
++	 * return the one after that.
++	 */
++	if (!msg->len) {
++		msg = (struct log *)log_buf;
++		return msg->len;
++	}
 +	return idx + msg->len;
 +}
 +
@@ -865,7 +875,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  
  #ifdef CONFIG_KEXEC
  /*
-@@ -165,9 +673,9 @@ static int saved_console_loglevel = -1;
+@@ -165,9 +683,9 @@ static int saved_console_loglevel = -1;
  void log_buf_kexec_setup(void)
  {
  	VMCOREINFO_SYMBOL(log_buf);
@@ -877,7 +887,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  }
  #endif
  
-@@ -191,7 +699,6 @@ early_param("log_buf_len", log_buf_len_s
+@@ -191,7 +709,6 @@ early_param("log_buf_len", log_buf_len_s
  void __init setup_log_buf(int early)
  {
  	unsigned long flags;
@@ -885,7 +895,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	char *new_log_buf;
  	int free;
  
-@@ -219,20 +726,8 @@ void __init setup_log_buf(int early)
+@@ -219,20 +736,8 @@ void __init setup_log_buf(int early)
  	log_buf_len = new_log_buf_len;
  	log_buf = new_log_buf;
  	new_log_buf_len = 0;
@@ -908,7 +918,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
  
  	pr_info("log_buf_len: %d\n", log_buf_len);
-@@ -332,11 +827,165 @@ static int check_syslog_permissions(int
+@@ -332,11 +837,165 @@ static int check_syslog_permissions(int
  	return 0;
  }
  
@@ -1077,7 +1087,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	int error;
  
  	error = check_syslog_permissions(type, from_file);
-@@ -364,28 +1013,14 @@ int do_syslog(int type, char __user *buf
+@@ -364,28 +1023,14 @@ int do_syslog(int type, char __user *buf
  			goto out;
  		}
  		error = wait_event_interruptible(log_wait,
@@ -1109,7 +1119,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  		/* FALL THRU */
  	/* Read last kernel messages */
  	case SYSLOG_ACTION_READ_ALL:
-@@ -399,52 +1034,11 @@ int do_syslog(int type, char __user *buf
+@@ -399,52 +1044,11 @@ int do_syslog(int type, char __user *buf
  			error = -EFAULT;
  			goto out;
  		}
@@ -1164,7 +1174,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	/* Disable logging to console */
  	case SYSLOG_ACTION_CONSOLE_OFF:
  		if (saved_console_loglevel == -1)
-@@ -472,7 +1066,33 @@ int do_syslog(int type, char __user *buf
+@@ -472,7 +1076,33 @@ int do_syslog(int type, char __user *buf
  		break;
  	/* Number of chars in the log buffer */
  	case SYSLOG_ACTION_SIZE_UNREAD:
@@ -1199,7 +1209,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  		break;
  	/* Size of the log buffer */
  	case SYSLOG_ACTION_SIZE_BUFFER:
-@@ -501,29 +1121,11 @@ void kdb_syslog_data(char *syslog_data[4
+@@ -501,29 +1131,11 @@ void kdb_syslog_data(char *syslog_data[4
  {
  	syslog_data[0] = log_buf;
  	syslog_data[1] = log_buf + log_buf_len;
@@ -1231,7 +1241,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  static bool __read_mostly ignore_loglevel;
  
  static int __init ignore_loglevel_setup(char *str)
-@@ -540,142 +1142,33 @@ MODULE_PARM_DESC(ignore_loglevel, "ignor
+@@ -540,142 +1152,33 @@ MODULE_PARM_DESC(ignore_loglevel, "ignor
  	"print all kernel messages to the console.");
  
  /*
@@ -1393,7 +1403,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  }
  
  /*
-@@ -700,16 +1193,6 @@ static void zap_locks(void)
+@@ -700,16 +1203,6 @@ static void zap_locks(void)
  	sema_init(&console_sem, 1);
  }
  
@@ -1410,7 +1420,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  /* Check if we have any console registered that can be called early in boot. */
  static int have_callable_console(void)
  {
-@@ -722,51 +1205,6 @@ static int have_callable_console(void)
+@@ -722,51 +1215,6 @@ static int have_callable_console(void)
  	return 0;
  }
  
@@ -1462,7 +1472,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  /*
   * Can we actually use the console at this time on this cpu?
   *
-@@ -810,17 +1248,12 @@ static int console_trylock_for_printk(un
+@@ -810,17 +1258,12 @@ static int console_trylock_for_printk(un
  			retval = 0;
  		}
  	}
@@ -1481,7 +1491,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  
  int printk_delay_msec __read_mostly;
  
-@@ -836,15 +1269,22 @@ static inline void printk_delay(void)
+@@ -836,15 +1279,22 @@ static inline void printk_delay(void)
  	}
  }
  
@@ -1511,7 +1521,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  
  	boot_delay_msec();
  	printk_delay();
-@@ -856,7 +1296,7 @@ asmlinkage int vprintk(const char *fmt,
+@@ -856,7 +1306,7 @@ asmlinkage int vprintk(const char *fmt,
  	/*
  	 * Ouch, printk recursed into itself!
  	 */
@@ -1520,7 +1530,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  		/*
  		 * If a crash is occurring during printk() on this CPU,
  		 * then try to get the crash message out but make sure
-@@ -873,97 +1313,92 @@ asmlinkage int vprintk(const char *fmt,
+@@ -873,97 +1323,92 @@ asmlinkage int vprintk(const char *fmt,
  
  	lockdep_off();
  	raw_spin_lock(&logbuf_lock);
@@ -1689,7 +1699,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	 */
  	if (console_trylock_for_printk(this_cpu))
  		console_unlock();
-@@ -974,12 +1409,73 @@ out_restore_irqs:
+@@ -974,12 +1419,73 @@ out_restore_irqs:
  
  	return printed_len;
  }
@@ -1765,7 +1775,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  {
  }
  
-@@ -1217,7 +1713,7 @@ int is_console_locked(void)
+@@ -1217,7 +1723,7 @@ int is_console_locked(void)
  }
  
  /*
@@ -1774,7 +1784,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
   */
  #define PRINTK_BUF_SIZE		512
  
-@@ -1253,6 +1749,10 @@ void wake_up_klogd(void)
+@@ -1253,6 +1759,10 @@ void wake_up_klogd(void)
  		this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
  }
  
@@ -1785,7 +1795,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  /**
   * console_unlock - unlock the console system
   *
-@@ -1263,15 +1763,16 @@ void wake_up_klogd(void)
+@@ -1263,15 +1773,16 @@ void wake_up_klogd(void)
   * by printk().  If this is the case, console_unlock(); emits
   * the output prior to releasing the lock.
   *
@@ -1805,7 +1815,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  
  	if (console_suspended) {
  		up(&console_sem);
-@@ -1281,17 +1782,41 @@ void console_unlock(void)
+@@ -1281,17 +1792,41 @@ void console_unlock(void)
  	console_may_schedule = 0;
  
  again:
@@ -1855,7 +1865,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  		start_critical_timings();
  		local_irq_restore(flags);
  	}
-@@ -1312,8 +1837,7 @@ again:
+@@ -1312,8 +1847,7 @@ again:
  	 * flush, no worries.
  	 */
  	raw_spin_lock(&logbuf_lock);
@@ -1865,7 +1875,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
  
  	if (retry && console_trylock())
-@@ -1549,7 +2073,8 @@ void register_console(struct console *ne
+@@ -1549,7 +2083,8 @@ void register_console(struct console *ne
  		 * for us.
  		 */
  		raw_spin_lock_irqsave(&logbuf_lock, flags);
@@ -1875,7 +1885,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  		raw_spin_unlock_irqrestore(&logbuf_lock, flags);
  		/*
  		 * We're about to replay the log buffer.  Only do this to the
-@@ -1758,6 +2283,9 @@ int kmsg_dump_unregister(struct kmsg_dum
+@@ -1758,6 +2293,9 @@ int kmsg_dump_unregister(struct kmsg_dum
  }
  EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
  
@@ -1885,7 +1895,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  /**
   * kmsg_dump - dump kernel log to kernel message dumpers.
   * @reason: the reason (oops, panic etc) for dumping
-@@ -1767,8 +2295,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
+@@ -1767,8 +2305,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
   */
  void kmsg_dump(enum kmsg_dump_reason reason)
  {
@@ -1895,7 +1905,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	struct kmsg_dumper *dumper;
  	const char *s1, *s2;
  	unsigned long l1, l2;
-@@ -1780,24 +2307,27 @@ void kmsg_dump(enum kmsg_dump_reason rea
+@@ -1780,24 +2317,27 @@ void kmsg_dump(enum kmsg_dump_reason rea
  	/* 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. */