more wrap-around fixes

1 files changed, 60 insertions, 48 deletions

diff --git a/printk.patch b/printk.patch
index 6e22b7c..2f252bd 100644
--- a/printk.patch
+++ b/printk.patch
@@ -98,8 +98,8 @@ 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        | 1369 +++++++++++++++++++++++++++++++++----------------
- 4 files changed, 1002 insertions(+), 469 deletions(-)
+ kernel/printk.c        | 1381 +++++++++++++++++++++++++++++++++----------------
+ 4 files changed, 1014 insertions(+), 469 deletions(-)
 
 --- a/drivers/base/core.c
 +++ b/drivers/base/core.c
@@ -303,7 +303,7 @@ 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 +127,525 @@ EXPORT_SYMBOL(console_set_on_cmdline);
+@@ -146,12 +127,536 @@ EXPORT_SYMBOL(console_set_on_cmdline);
  static int console_may_schedule;
  
  #ifdef CONFIG_PRINTK
@@ -458,23 +458,34 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
 +	return (char *)msg + sizeof(struct log) + msg->text_len;
 +}
 +
-+/* get record by index */
++/* get record by index; idx must point to valid msg */
 +static struct log *log_from_idx(u32 idx)
 +{
-+	return (struct log *)&log_buf[idx];
++	struct log *msg = (struct log *)(log_buf + idx);
++
++	/* length == 0 indicates the end of the buffer; wrap */
++	if (!msg->len)
++		return (struct log *)log_buf;
++	return msg;
 +}
 +
-+/* get next record; log_next_idx indicates the last record */
++/* get next record; idx must point to valid msg */
 +static u32 log_next(u32 idx)
 +{
-+	u16 len = log_from_idx(idx)->len;
++	struct log *msg = (struct log *)(log_buf + idx);
 +
 +	/* length == 0 indicates the end of the buffer; wrap */
-+	if (log_from_idx(idx + len)->len == 0)
++	if (!msg->len)
 +		return 0;
-+	return idx + len;
++	return idx + msg->len;
 +}
 +
++#if !defined(CONFIG_64BIT) || defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
++#define LOG_ALIGN 4
++#else
++#define LOG_ALIGN 8
++#endif
++
 +/* insert record into the buffer, discard old ones, update heads */
 +static void log_store(int facility, int level,
 +		      const char *dict, u16 dict_len,
@@ -485,37 +496,37 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
 +
 +	/* number of '\0' padding bytes to next message */
 +	size = sizeof(struct log) + text_len + dict_len;
-+	pad_len = (-size) & (8 - 1);
++	pad_len = (-size) & (LOG_ALIGN - 1);
 +	size += pad_len;
 +
-+	/* drop old messages until we have enough contiuous space */
 +	while (log_first_seq < log_next_seq) {
 +		u32 free;
 +
-+		if (log_next_idx >= log_first_idx)
++		if (log_next_idx > log_first_idx)
 +			free = max(log_buf_len - log_next_idx, log_first_idx);
 +		else
 +			free = log_first_idx - log_next_idx;
 +
-+		if (free >= size + sizeof(struct log))
++		if (free > size + sizeof(struct log))
 +			break;
 +
++		/* drop old messages until we have enough contiuous space */
 +		log_first_idx = log_next(log_first_idx);
 +		log_first_seq++;
 +	}
 +
-+	if (log_next_idx + size + sizeof(struct log) > log_buf_len) {
++	if (log_next_idx + size + sizeof(struct log) >= log_buf_len) {
 +		/*
-+		 * This message + empty last message does not fit at the
-+		 * end; wrap. Zero-out the remaining buffer to set len = 0,
-+		 * and leave a clean buffer for things like crash dump.
++		 * This message + an additional empty header does not fit
++		 * at the end of the buffer. Add an empty header with len = 0
++		 * to signify a wrap around.
 +		 */
-+		memset(log_buf + log_next_idx, 0, log_buf_len - log_next_idx);
++		memset(log_buf + log_next_idx, 0, sizeof(struct log));
 +		log_next_idx = 0;
 +	}
 +
 +	/* fill message */
-+	msg = log_from_idx(log_next_idx);
++	msg = (struct log *)(log_buf + log_next_idx);
 +	memcpy(log_text(msg), text, text_len);
 +	msg->text_len = text_len;
 +	memcpy(log_dict(msg), dict, dict_len);
@@ -832,7 +843,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  
  #ifdef CONFIG_KEXEC
  /*
-@@ -165,9 +659,9 @@ static int saved_console_loglevel = -1;
+@@ -165,9 +670,9 @@ static int saved_console_loglevel = -1;
  void log_buf_kexec_setup(void)
  {
  	VMCOREINFO_SYMBOL(log_buf);
@@ -844,7 +855,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  }
  #endif
  
-@@ -191,7 +685,6 @@ early_param("log_buf_len", log_buf_len_s
+@@ -191,7 +696,6 @@ early_param("log_buf_len", log_buf_len_s
  void __init setup_log_buf(int early)
  {
  	unsigned long flags;
@@ -852,7 +863,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	char *new_log_buf;
  	int free;
  
-@@ -219,20 +712,8 @@ void __init setup_log_buf(int early)
+@@ -219,20 +723,8 @@ void __init setup_log_buf(int early)
  	log_buf_len = new_log_buf_len;
  	log_buf = new_log_buf;
  	new_log_buf_len = 0;
@@ -875,7 +886,7 @@ 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 +813,165 @@ static int check_syslog_permissions(int
+@@ -332,11 +824,165 @@ static int check_syslog_permissions(int
  	return 0;
  }
  
@@ -1044,7 +1055,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	int error;
  
  	error = check_syslog_permissions(type, from_file);
-@@ -364,28 +999,14 @@ int do_syslog(int type, char __user *buf
+@@ -364,28 +1010,14 @@ int do_syslog(int type, char __user *buf
  			goto out;
  		}
  		error = wait_event_interruptible(log_wait,
@@ -1076,7 +1087,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  		/* FALL THRU */
  	/* Read last kernel messages */
  	case SYSLOG_ACTION_READ_ALL:
-@@ -399,52 +1020,11 @@ int do_syslog(int type, char __user *buf
+@@ -399,52 +1031,11 @@ int do_syslog(int type, char __user *buf
  			error = -EFAULT;
  			goto out;
  		}
@@ -1131,7 +1142,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	/* Disable logging to console */
  	case SYSLOG_ACTION_CONSOLE_OFF:
  		if (saved_console_loglevel == -1)
-@@ -472,7 +1052,33 @@ int do_syslog(int type, char __user *buf
+@@ -472,7 +1063,33 @@ int do_syslog(int type, char __user *buf
  		break;
  	/* Number of chars in the log buffer */
  	case SYSLOG_ACTION_SIZE_UNREAD:
@@ -1144,7 +1155,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
 +		}
 +		if (from_file) {
 +			/*
-+			 * Optimize for poll(/"proc/kmsg") which simply checks
++			 * Short-cut for poll(/"proc/kmsg") which simply checks
 +			 * for pending data, not the size; return the count of
 +			 * records, not the length.
 +			 */
@@ -1166,7 +1177,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  		break;
  	/* Size of the log buffer */
  	case SYSLOG_ACTION_SIZE_BUFFER:
-@@ -501,29 +1107,11 @@ void kdb_syslog_data(char *syslog_data[4
+@@ -501,29 +1118,11 @@ void kdb_syslog_data(char *syslog_data[4
  {
  	syslog_data[0] = log_buf;
  	syslog_data[1] = log_buf + log_buf_len;
@@ -1198,7 +1209,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  static bool __read_mostly ignore_loglevel;
  
  static int __init ignore_loglevel_setup(char *str)
-@@ -540,142 +1128,33 @@ MODULE_PARM_DESC(ignore_loglevel, "ignor
+@@ -540,142 +1139,33 @@ MODULE_PARM_DESC(ignore_loglevel, "ignor
  	"print all kernel messages to the console.");
  
  /*
@@ -1360,7 +1371,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  }
  
  /*
-@@ -700,16 +1179,6 @@ static void zap_locks(void)
+@@ -700,16 +1190,6 @@ static void zap_locks(void)
  	sema_init(&console_sem, 1);
  }
  
@@ -1377,7 +1388,7 @@ 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 +1191,6 @@ static int have_callable_console(void)
+@@ -722,51 +1202,6 @@ static int have_callable_console(void)
  	return 0;
  }
  
@@ -1429,7 +1440,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  /*
   * Can we actually use the console at this time on this cpu?
   *
-@@ -810,17 +1234,12 @@ static int console_trylock_for_printk(un
+@@ -810,17 +1245,12 @@ static int console_trylock_for_printk(un
  			retval = 0;
  		}
  	}
@@ -1448,7 +1459,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  
  int printk_delay_msec __read_mostly;
  
-@@ -836,15 +1255,22 @@ static inline void printk_delay(void)
+@@ -836,15 +1266,22 @@ static inline void printk_delay(void)
  	}
  }
  
@@ -1478,7 +1489,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  
  	boot_delay_msec();
  	printk_delay();
-@@ -856,7 +1282,7 @@ asmlinkage int vprintk(const char *fmt,
+@@ -856,7 +1293,7 @@ asmlinkage int vprintk(const char *fmt,
  	/*
  	 * Ouch, printk recursed into itself!
  	 */
@@ -1487,7 +1498,7 @@ 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 +1299,92 @@ asmlinkage int vprintk(const char *fmt,
+@@ -873,97 +1310,92 @@ asmlinkage int vprintk(const char *fmt,
  
  	lockdep_off();
  	raw_spin_lock(&logbuf_lock);
@@ -1656,7 +1667,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	 */
  	if (console_trylock_for_printk(this_cpu))
  		console_unlock();
-@@ -974,12 +1395,73 @@ out_restore_irqs:
+@@ -974,12 +1406,73 @@ out_restore_irqs:
  
  	return printed_len;
  }
@@ -1732,7 +1743,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  {
  }
  
-@@ -1217,7 +1699,7 @@ int is_console_locked(void)
+@@ -1217,7 +1710,7 @@ int is_console_locked(void)
  }
  
  /*
@@ -1741,7 +1752,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
   */
  #define PRINTK_BUF_SIZE		512
  
-@@ -1253,6 +1735,10 @@ void wake_up_klogd(void)
+@@ -1253,6 +1746,10 @@ void wake_up_klogd(void)
  		this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
  }
  
@@ -1752,7 +1763,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  /**
   * console_unlock - unlock the console system
   *
-@@ -1263,15 +1749,16 @@ void wake_up_klogd(void)
+@@ -1263,15 +1760,16 @@ void wake_up_klogd(void)
   * by printk().  If this is the case, console_unlock(); emits
   * the output prior to releasing the lock.
   *
@@ -1772,7 +1783,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  
  	if (console_suspended) {
  		up(&console_sem);
-@@ -1281,17 +1768,40 @@ void console_unlock(void)
+@@ -1281,17 +1779,41 @@ void console_unlock(void)
  	console_may_schedule = 0;
  
  again:
@@ -1795,14 +1806,15 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
 +			seen_seq = log_next_seq;
 +		}
 +
-+		if (console_seq == log_next_seq)
-+			break;
-+
 +		if (console_seq < log_first_seq) {
 +			/* messages are gone, move to first one */
 +			console_seq = log_first_seq;
 +			console_idx = log_first_idx;
 +		}
++
++		if (console_seq == log_next_seq)
++			break;
++
 +		msg = log_from_idx(console_idx);
 +		level = msg->level;
 +		len = msg->text_len;
@@ -1821,7 +1833,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  		start_critical_timings();
  		local_irq_restore(flags);
  	}
-@@ -1312,8 +1822,7 @@ again:
+@@ -1312,8 +1834,7 @@ again:
  	 * flush, no worries.
  	 */
  	raw_spin_lock(&logbuf_lock);
@@ -1831,7 +1843,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
  
  	if (retry && console_trylock())
-@@ -1549,7 +2058,8 @@ void register_console(struct console *ne
+@@ -1549,7 +2070,8 @@ void register_console(struct console *ne
  		 * for us.
  		 */
  		raw_spin_lock_irqsave(&logbuf_lock, flags);
@@ -1841,7 +1853,7 @@ 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 +2268,9 @@ int kmsg_dump_unregister(struct kmsg_dum
+@@ -1758,6 +2280,9 @@ int kmsg_dump_unregister(struct kmsg_dum
  }
  EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
  
@@ -1851,7 +1863,7 @@ 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 +2280,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
+@@ -1767,8 +2292,7 @@ EXPORT_SYMBOL_GPL(kmsg_dump_unregister);
   */
  void kmsg_dump(enum kmsg_dump_reason reason)
  {
@@ -1861,7 +1873,7 @@ Signed-off-by: Kay Sievers <kay@vrfy.org>
  	struct kmsg_dumper *dumper;
  	const char *s1, *s2;
  	unsigned long l1, l2;
-@@ -1780,24 +2292,27 @@ void kmsg_dump(enum kmsg_dump_reason rea
+@@ -1780,24 +2304,27 @@ 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. */