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Message-ID: <20121119142926.GB4453@mail.hallyn.com>
Date:	Mon, 19 Nov 2012 14:29:26 +0000
From:	"Serge E. Hallyn" <serge@...lyn.com>
To:	Rui Xiang <leo.ruixiang@...il.com>
Cc:	serge.hallyn@...onical.com, containers@...ts.linux-foundation.org,
	netdev@...r.kernel.org, "Eric W. Biederman" <ebiederm@...ssion.com>
Subject: Re: [PATCH RFC 3/5] printk: modify printk interface for
 syslog_namespace

Quoting Rui Xiang (leo.ruixiang@...il.com):
> From: Libo Chen <clbchenlibo.chen@...wei.com>
> 
> We re-implement printk by additional syslog_ns.
> 
> The function include printk, /dev/kmsg, do_syslog and kmsg_dump should be modifyed
> for syslog_ns. Previous identifier *** such as log_first_seq should be replaced
> by syslog_ns->***.
> 
> Signed-off-by: Libo Chen <clbchenlibo.chen@...wei.com>
> Signed-off-by: Xiang Rui <rui.xiang@...wei.com>
> ---
>  drivers/base/core.c    |    4 +-
>  include/linux/printk.h |    4 +-
>  kernel/printk.c        |  609 +++++++++++++++++++++++++++++-------------------
>  3 files changed, 372 insertions(+), 245 deletions(-)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index abea76c..665c2f7 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -26,6 +26,7 @@
>  #include <linux/async.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/netdevice.h>
> +#include <linux/syslog_namespace.h>
> 
>  #include "base.h"
>  #include "power/power.h"
> @@ -1922,7 +1923,8 @@ int dev_vprintk_emit(int level, const struct device *dev,
> 
>  	hdrlen = create_syslog_header(dev, hdr, sizeof(hdr));
> 
> -	return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen, fmt, args);
> +	return vprintk_emit(0, level, hdrlen ? hdr : NULL, hdrlen,
> +				fmt, args, current_syslog_ns());
>  }
>  EXPORT_SYMBOL(dev_vprintk_emit);
> 
> diff --git a/include/linux/printk.h b/include/linux/printk.h
> index 9afc01e..e0c60d9 100644
> --- a/include/linux/printk.h
> +++ b/include/linux/printk.h
> @@ -7,6 +7,7 @@
>  extern const char linux_banner[];
>  extern const char linux_proc_banner[];
> 
> +struct syslog_namespace;
>  static inline int printk_get_level(const char *buffer)
>  {
>  	if (buffer[0] == KERN_SOH_ASCII && buffer[1]) {
> @@ -105,7 +106,8 @@ extern void printk_tick(void);
>  asmlinkage __printf(5, 0)
>  int vprintk_emit(int facility, int level,
>  		 const char *dict, size_t dictlen,
> -		 const char *fmt, va_list args);
> +		 const char *fmt, va_list args,
> +		 struct syslog_namespace *syslog_ns);
> 
>  asmlinkage __printf(1, 0)
>  int vprintk(const char *fmt, va_list args);
> diff --git a/kernel/printk.c b/kernel/printk.c
> index 2d607f4..2ef9c46 100644
> --- a/kernel/printk.c
> +++ b/kernel/printk.c
> @@ -42,6 +42,7 @@
>  #include <linux/notifier.h>
>  #include <linux/rculist.h>
>  #include <linux/poll.h>
> +#include <linux/syslog_namespace.h>
> 
>  #include <asm/uaccess.h>
> 
> @@ -214,46 +215,14 @@ struct log {
>   * The logbuf_lock protects kmsg buffer, indices, counters. It is also
>   * used in interesting ways to provide interlocking in console_unlock();
>   */
> -static DEFINE_RAW_SPINLOCK(logbuf_lock);
> 
>  #ifdef CONFIG_PRINTK
> -/* the next printk record to read by syslog(READ) or /proc/kmsg */
> -static u64 syslog_seq;
> -static u32 syslog_idx;
> -static enum log_flags syslog_prev;
> -static size_t syslog_partial;
> -
> -/* index and sequence number of the first record stored in the buffer */
> -static u64 log_first_seq;
> -static u32 log_first_idx;
> -
> -/* index and sequence number of the next record to store in the buffer */
> -static u64 log_next_seq;
> -static u32 log_next_idx;
> 
> -/* the next printk record to write to the console */
> -static u64 console_seq;
> -static u32 console_idx;
>  static enum log_flags console_prev;
> 
> -/* the next printk record to read after the last 'clear' command */
> -static u64 clear_seq;
> -static u32 clear_idx;
> -
>  #define PREFIX_MAX		32
>  #define LOG_LINE_MAX		1024 - PREFIX_MAX
> 
> -/* record buffer */
> -#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
> -#define LOG_ALIGN 4
> -#else
> -#define LOG_ALIGN __alignof__(struct log)
> -#endif
> -#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
> -static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
> -static char *log_buf = __log_buf;
> -static u32 log_buf_len = __LOG_BUF_LEN;
> -
>  /* cpu currently holding logbuf_lock */
>  static volatile unsigned int logbuf_cpu = UINT_MAX;
> 
> @@ -270,23 +239,23 @@ static char *log_dict(const struct log *msg)
>  }
> 
>  /* get record by index; idx must point to valid msg */
> -static struct log *log_from_idx(u32 idx)
> +static struct log *log_from_idx(u32 idx, struct syslog_namespace *syslog_ns)
>  {
> -	struct log *msg = (struct log *)(log_buf + idx);
> +	struct log *msg = (struct log *)(syslog_ns->log_buf + idx);
> 
>  	/*
>  	 * 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 (struct log *)syslog_ns->log_buf;
>  	return msg;
>  }
> 
>  /* get next record; idx must point to valid msg */
> -static u32 log_next(u32 idx)
> +static u32 log_next(u32 idx, struct syslog_namespace *syslog_ns)
>  {
> -	struct log *msg = (struct log *)(log_buf + idx);
> +	struct log *msg = (struct log *)(syslog_ns->log_buf + idx);
> 
>  	/* length == 0 indicates the end of the buffer; wrap */
>  	/*
> @@ -295,7 +264,7 @@ static u32 log_next(u32 idx)
>  	 * return the one after that.
>  	 */
>  	if (!msg->len) {
> -		msg = (struct log *)log_buf;
> +		msg = (struct log *)syslog_ns->log_buf;
>  		return msg->len;
>  	}
>  	return idx + msg->len;
> @@ -305,7 +274,8 @@ static u32 log_next(u32 idx)
>  static void log_store(int facility, int level,
>  		      enum log_flags flags, u64 ts_nsec,
>  		      const char *dict, u16 dict_len,
> -		      const char *text, u16 text_len)
> +		      const char *text, u16 text_len,
> +		      struct syslog_namespace *syslog_ns)
>  {
>  	struct log *msg;
>  	u32 size, pad_len;
> @@ -315,34 +285,40 @@ static void log_store(int facility, int level,
>  	pad_len = (-size) & (LOG_ALIGN - 1);
>  	size += pad_len;
> 
> -	while (log_first_seq < log_next_seq) {
> +	while (syslog_ns->log_first_seq < syslog_ns->log_next_seq) {
>  		u32 free;
> 
> -		if (log_next_idx > log_first_idx)
> -			free = max(log_buf_len - log_next_idx, log_first_idx);
> +		if (syslog_ns->log_next_idx > syslog_ns->log_first_idx)
> +			free = max(syslog_ns->log_buf_len -
> +				 syslog_ns->log_next_idx,
> +				 syslog_ns->log_first_idx);
>  		else
> -			free = log_first_idx - log_next_idx;
> +			free = syslog_ns->log_first_idx -
> +					 syslog_ns->log_next_idx;
> 
>  		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++;
> +		syslog_ns->log_first_idx =
> +				log_next(syslog_ns->log_first_idx, syslog_ns);
> +		syslog_ns->log_first_seq++;
>  	}
> 
> -	if (log_next_idx + size + sizeof(struct log) >= log_buf_len) {
> +	if (syslog_ns->log_next_idx + size + sizeof(struct log) >=
> +						 syslog_ns->log_buf_len) {
>  		/*
>  		 * 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, sizeof(struct log));
> -		log_next_idx = 0;
> +		memset(syslog_ns->log_buf + syslog_ns->log_next_idx,
> +						 0, sizeof(struct log));
> +		syslog_ns->log_next_idx = 0;
>  	}
> 
>  	/* fill message */
> -	msg = (struct log *)(log_buf + log_next_idx);
> +	msg = (struct log *)(syslog_ns->log_buf + syslog_ns->log_next_idx);
>  	memcpy(log_text(msg), text, text_len);
>  	msg->text_len = text_len;
>  	memcpy(log_dict(msg), dict, dict_len);
> @@ -358,8 +334,8 @@ static void log_store(int facility, int level,
>  	msg->len = sizeof(struct log) + text_len + dict_len + pad_len;
> 
>  	/* insert message */
> -	log_next_idx += msg->len;
> -	log_next_seq++;
> +	syslog_ns->log_next_idx += msg->len;
> +	syslog_ns->log_next_seq++;
>  }
> 
>  /* /dev/kmsg - userspace message inject/listen interface */
> @@ -368,6 +344,7 @@ struct devkmsg_user {
>  	u32 idx;
>  	enum log_flags prev;
>  	struct mutex lock;
> +	struct syslog_namespace *syslog_ns;
>  	char buf[8192];
>  };
> 
> @@ -431,6 +408,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
>  			    size_t count, loff_t *ppos)
>  {
>  	struct devkmsg_user *user = file->private_data;
> +	struct syslog_namespace *syslog_ns = user->syslog_ns;
>  	struct log *msg;
>  	u64 ts_usec;
>  	size_t i;
> @@ -444,32 +422,32 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
>  	ret = mutex_lock_interruptible(&user->lock);
>  	if (ret)
>  		return ret;
> -	raw_spin_lock_irq(&logbuf_lock);
> -	while (user->seq == log_next_seq) {
> +	raw_spin_lock_irq(&syslog_ns->logbuf_lock);
> +	while (user->seq == syslog_ns->log_next_seq) {
>  		if (file->f_flags & O_NONBLOCK) {
>  			ret = -EAGAIN;
> -			raw_spin_unlock_irq(&logbuf_lock);
> +			raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
>  			goto out;
>  		}
> 
> -		raw_spin_unlock_irq(&logbuf_lock);
> +		raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
>  		ret = wait_event_interruptible(log_wait,
> -					       user->seq != log_next_seq);
> +				user->seq != syslog_ns->log_next_seq);
>  		if (ret)
>  			goto out;
> -		raw_spin_lock_irq(&logbuf_lock);
> +		raw_spin_lock_irq(&syslog_ns->logbuf_lock);
>  	}
> 
> -	if (user->seq < log_first_seq) {
> +	if (user->seq < syslog_ns->log_first_seq) {
>  		/* our last seen message is gone, return error and reset */
> -		user->idx = log_first_idx;
> -		user->seq = log_first_seq;
> +		user->idx = syslog_ns->log_first_idx;
> +		user->seq = syslog_ns->log_first_seq;
>  		ret = -EPIPE;
> -		raw_spin_unlock_irq(&logbuf_lock);
> +		raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
>  		goto out;
>  	}
> 
> -	msg = log_from_idx(user->idx);
> +	msg = log_from_idx(user->idx, syslog_ns);
>  	ts_usec = msg->ts_nsec;
>  	do_div(ts_usec, 1000);
> 
> @@ -530,9 +508,9 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
>  		user->buf[len++] = '\n';
>  	}
> 
> -	user->idx = log_next(user->idx);
> +	user->idx = log_next(user->idx, syslog_ns);
>  	user->seq++;
> -	raw_spin_unlock_irq(&logbuf_lock);
> +	raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
> 
>  	if (len > count) {
>  		ret = -EINVAL;
> @@ -552,6 +530,7 @@ out:
>  static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
>  {
>  	struct devkmsg_user *user = file->private_data;
> +	struct syslog_namespace *syslog_ns = user->syslog_ns;
>  	loff_t ret = 0;
> 
>  	if (!user)
> @@ -559,12 +538,12 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
>  	if (offset)
>  		return -ESPIPE;
> 
> -	raw_spin_lock_irq(&logbuf_lock);
> +	raw_spin_lock_irq(&syslog_ns->logbuf_lock);
>  	switch (whence) {
>  	case SEEK_SET:
>  		/* the first record */
> -		user->idx = log_first_idx;
> -		user->seq = log_first_seq;
> +		user->idx = syslog_ns->log_first_idx;
> +		user->seq = syslog_ns->log_first_seq;
>  		break;
>  	case SEEK_DATA:
>  		/*
> @@ -572,24 +551,25 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
>  		 * like issued by 'dmesg -c'. Reading /dev/kmsg itself
>  		 * changes no global state, and does not clear anything.
>  		 */
> -		user->idx = clear_idx;
> -		user->seq = clear_seq;
> +		user->idx = syslog_ns->clear_idx;
> +		user->seq = syslog_ns->clear_seq;
>  		break;
>  	case SEEK_END:
>  		/* after the last record */
> -		user->idx = log_next_idx;
> -		user->seq = log_next_seq;
> +		user->idx = syslog_ns->log_next_idx;
> +		user->seq = syslog_ns->log_next_seq;
>  		break;
>  	default:
>  		ret = -EINVAL;
>  	}
> -	raw_spin_unlock_irq(&logbuf_lock);
> +	raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
>  	return ret;
>  }
> 
>  static unsigned int devkmsg_poll(struct file *file, poll_table *wait)
>  {
>  	struct devkmsg_user *user = file->private_data;
> +	struct syslog_namespace *syslog_ns = user->syslog_ns;
>  	int ret = 0;
> 
>  	if (!user)
> @@ -597,20 +577,21 @@ static unsigned int devkmsg_poll(struct file *file, poll_table *wait)
> 
>  	poll_wait(file, &log_wait, wait);
> 
> -	raw_spin_lock_irq(&logbuf_lock);
> -	if (user->seq < log_next_seq) {
> +	raw_spin_lock_irq(&syslog_ns->logbuf_lock);
> +	if (user->seq < syslog_ns->log_next_seq) {
>  		/* return error when data has vanished underneath us */
> -		if (user->seq < log_first_seq)
> +		if (user->seq < syslog_ns->log_first_seq)
>  			ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI;
>  		ret = POLLIN|POLLRDNORM;
>  	}
> -	raw_spin_unlock_irq(&logbuf_lock);
> +	raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
> 
>  	return ret;
>  }
> 
>  static int devkmsg_open(struct inode *inode, struct file *file)
>  {
> +	struct syslog_namespace *syslog_ns;
>  	struct devkmsg_user *user;
>  	int err;
> 
> @@ -628,10 +609,11 @@ static int devkmsg_open(struct inode *inode, struct file *file)
> 
>  	mutex_init(&user->lock);
> 
> -	raw_spin_lock_irq(&logbuf_lock);
> -	user->idx = log_first_idx;
> -	user->seq = log_first_seq;
> -	raw_spin_unlock_irq(&logbuf_lock);
> +	user->syslog_ns = current_syslog_ns();
> +	raw_spin_lock_irq(&syslog_ns->logbuf_lock);
> +	user->idx = syslog_ns->log_first_idx;
> +	user->seq = syslog_ns->log_first_seq;
> +	raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
> 
>  	file->private_data = user;
>  	return 0;
> @@ -669,10 +651,12 @@ const struct file_operations kmsg_fops = {
>   */
>  void log_buf_kexec_setup(void)
>  {
> -	VMCOREINFO_SYMBOL(log_buf);
> -	VMCOREINFO_SYMBOL(log_buf_len);
> -	VMCOREINFO_SYMBOL(log_first_idx);
> -	VMCOREINFO_SYMBOL(log_next_idx);
> +	struct syslog_namespace *syslog_ns = current_syslog_ns();
> +
> +	VMCOREINFO_SYMBOL(syslog_ns->log_buf);
> +	VMCOREINFO_SYMBOL(syslog_ns->log_buf_len);
> +	VMCOREINFO_SYMBOL(syslog_ns->log_first_idx);
> +	VMCOREINFO_SYMBOL(syslog_ns->log_next_idx);
>  	/*
>  	 * Export struct log size and field offsets. User space tools can
>  	 * parse it and detect any changes to structure down the line.
> @@ -692,10 +676,11 @@ static unsigned long __initdata new_log_buf_len;
>  static int __init log_buf_len_setup(char *str)
>  {
>  	unsigned size = memparse(str, &str);
> +	struct syslog_namespace *syslog_ns = &init_syslog_ns;
> 
>  	if (size)
>  		size = roundup_pow_of_two(size);
> -	if (size > log_buf_len)
> +	if (size > syslog_ns->log_buf_len)
>  		new_log_buf_len = size;
> 
>  	return 0;
> @@ -707,6 +692,7 @@ void __init setup_log_buf(int early)
>  	unsigned long flags;
>  	char *new_log_buf;
>  	int free;
> +	struct syslog_namespace *syslog_ns = &init_syslog_ns;
> 
>  	if (!new_log_buf_len)
>  		return;
> @@ -728,15 +714,15 @@ void __init setup_log_buf(int early)
>  		return;
>  	}
> 
> -	raw_spin_lock_irqsave(&logbuf_lock, flags);
> -	log_buf_len = new_log_buf_len;
> -	log_buf = new_log_buf;
> +	raw_spin_lock_irqsave(&syslog_ns->logbuf_lock, flags);
> +	memcpy(new_log_buf, syslog_ns->log_buf, __LOG_BUF_LEN);
> +	syslog_ns->log_buf_len = new_log_buf_len;
> +	syslog_ns->log_buf = new_log_buf;
>  	new_log_buf_len = 0;
> -	free = __LOG_BUF_LEN - log_next_idx;
> -	memcpy(log_buf, __log_buf, __LOG_BUF_LEN);
> -	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
> +	free = __LOG_BUF_LEN - syslog_ns->log_next_idx;
> +	raw_spin_unlock_irqrestore(&syslog_ns->logbuf_lock, flags);
> 
> -	pr_info("log_buf_len: %d\n", log_buf_len);
> +	pr_info("log_buf_len: %d\n", syslog_ns->log_buf_len);
>  	pr_info("early log buf free: %d(%d%%)\n",
>  		free, (free * 100) / __LOG_BUF_LEN);
>  }
> @@ -937,7 +923,8 @@ static size_t msg_print_text(const struct log *msg, enum log_flags prev,
>  	return len;
>  }
> 
> -static int syslog_print(char __user *buf, int size)
> +static int syslog_print(char __user *buf, int size,
> +			 struct syslog_namespace *syslog_ns)
>  {
>  	char *text;
>  	struct log *msg;
> @@ -951,37 +938,38 @@ static int syslog_print(char __user *buf, int size)
>  		size_t n;
>  		size_t skip;
> 
> -		raw_spin_lock_irq(&logbuf_lock);
> -		if (syslog_seq < log_first_seq) {
> +		raw_spin_lock_irq(&syslog_ns->logbuf_lock);
> +		if (syslog_ns->syslog_seq < syslog_ns->log_first_seq) {
>  			/* messages are gone, move to first one */
> -			syslog_seq = log_first_seq;
> -			syslog_idx = log_first_idx;
> -			syslog_prev = 0;
> -			syslog_partial = 0;
> +			syslog_ns->syslog_seq = syslog_ns->log_first_seq;
> +			syslog_ns->syslog_idx = syslog_ns->log_first_idx;
> +			syslog_ns->syslog_prev = 0;
> +			syslog_ns->syslog_partial = 0;
>  		}
> -		if (syslog_seq == log_next_seq) {
> -			raw_spin_unlock_irq(&logbuf_lock);
> +		if (syslog_ns->syslog_seq == syslog_ns->log_next_seq) {
> +			raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
>  			break;
>  		}
> 
> -		skip = syslog_partial;
> -		msg = log_from_idx(syslog_idx);
> -		n = msg_print_text(msg, syslog_prev, true, text,
> +		skip = syslog_ns->syslog_partial;
> +		msg = log_from_idx(syslog_ns->syslog_idx, syslog_ns);
> +		n = msg_print_text(msg, syslog_ns->syslog_prev, true, text,
>  				   LOG_LINE_MAX + PREFIX_MAX);
> -		if (n - syslog_partial <= size) {
> +		if (n - syslog_ns->syslog_partial <= size) {
>  			/* message fits into buffer, move forward */
> -			syslog_idx = log_next(syslog_idx);
> -			syslog_seq++;
> -			syslog_prev = msg->flags;
> -			n -= syslog_partial;
> -			syslog_partial = 0;
> +			syslog_ns->syslog_idx =
> +				log_next(syslog_ns->syslog_idx, syslog_ns);
> +			syslog_ns->syslog_seq++;
> +			syslog_ns->syslog_prev = msg->flags;
> +			n -= syslog_ns->syslog_partial;
> +			syslog_ns->syslog_partial = 0;
>  		} else if (!len){
>  			/* partial read(), remember position */
>  			n = size;
> -			syslog_partial += n;
> +			syslog_ns->syslog_partial += n;
>  		} else
>  			n = 0;
> -		raw_spin_unlock_irq(&logbuf_lock);
> +		raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
> 
>  		if (!n)
>  			break;
> @@ -1001,7 +989,8 @@ static int syslog_print(char __user *buf, int size)
>  	return len;
>  }
> 
> -static int syslog_print_all(char __user *buf, int size, bool clear)
> +static int syslog_print_all(char __user *buf, int size, bool clear,
> +				struct syslog_namespace *syslog_ns)
>  {
>  	char *text;
>  	int len = 0;
> @@ -1010,55 +999,55 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
>  	if (!text)
>  		return -ENOMEM;
> 
> -	raw_spin_lock_irq(&logbuf_lock);
> +	raw_spin_lock_irq(&syslog_ns->logbuf_lock);
>  	if (buf) {
>  		u64 next_seq;
>  		u64 seq;
>  		u32 idx;
>  		enum log_flags prev;
> 
> -		if (clear_seq < log_first_seq) {
> +		if (syslog_ns->clear_seq < syslog_ns->log_first_seq) {
>  			/* messages are gone, move to first available one */
> -			clear_seq = log_first_seq;
> -			clear_idx = log_first_idx;
> +			syslog_ns->clear_seq = syslog_ns->log_first_seq;
> +			syslog_ns->clear_idx = syslog_ns->log_first_idx;
>  		}
> 
>  		/*
>  		 * Find first record that fits, including all following records,
>  		 * into the user-provided buffer for this dump.
>  		 */
> -		seq = clear_seq;
> -		idx = clear_idx;
> +		seq = syslog_ns->clear_seq;
> +		idx = syslog_ns->clear_idx;
>  		prev = 0;
> -		while (seq < log_next_seq) {
> -			struct log *msg = log_from_idx(idx);
> +		while (seq < syslog_ns->log_next_seq) {
> +			struct log *msg = log_from_idx(idx, syslog_ns);
> 
>  			len += msg_print_text(msg, prev, true, NULL, 0);
>  			prev = msg->flags;
> -			idx = log_next(idx);
> +			idx = log_next(idx, syslog_ns);
>  			seq++;
>  		}
> 
>  		/* move first record forward until length fits into the buffer */
> -		seq = clear_seq;
> -		idx = clear_idx;
> +		seq = syslog_ns->clear_seq;
> +		idx = syslog_ns->clear_idx;
>  		prev = 0;
> -		while (len > size && seq < log_next_seq) {
> -			struct log *msg = log_from_idx(idx);
> +		while (len > size && seq < syslog_ns->log_next_seq) {
> +			struct log *msg = log_from_idx(idx, syslog_ns);
> 
>  			len -= msg_print_text(msg, prev, true, NULL, 0);
>  			prev = msg->flags;
> -			idx = log_next(idx);
> +			idx = log_next(idx, syslog_ns);
>  			seq++;
>  		}
> 
>  		/* last message fitting into this dump */
> -		next_seq = log_next_seq;
> +		next_seq = syslog_ns->log_next_seq;
> 
>  		len = 0;
>  		prev = 0;
>  		while (len >= 0 && seq < next_seq) {
> -			struct log *msg = log_from_idx(idx);
> +			struct log *msg = log_from_idx(idx, syslog_ns);
>  			int textlen;
> 
>  			textlen = msg_print_text(msg, prev, true, text,
> @@ -1067,31 +1056,31 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
>  				len = textlen;
>  				break;
>  			}
> -			idx = log_next(idx);
> +			idx = log_next(idx, syslog_ns);
>  			seq++;
>  			prev = msg->flags;
> 
> -			raw_spin_unlock_irq(&logbuf_lock);
> +			raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
>  			if (copy_to_user(buf + len, text, textlen))
>  				len = -EFAULT;
>  			else
>  				len += textlen;
> -			raw_spin_lock_irq(&logbuf_lock);
> +			raw_spin_lock_irq(&syslog_ns->logbuf_lock);
> 
> -			if (seq < log_first_seq) {
> +			if (seq < syslog_ns->log_first_seq) {
>  				/* messages are gone, move to next one */
> -				seq = log_first_seq;
> -				idx = log_first_idx;
> +				seq = syslog_ns->log_first_seq;
> +				idx = syslog_ns->log_first_idx;
>  				prev = 0;
>  			}
>  		}
>  	}
> 
>  	if (clear) {
> -		clear_seq = log_next_seq;
> -		clear_idx = log_next_idx;
> +		syslog_ns->clear_seq = syslog_ns->log_next_seq;
> +		syslog_ns->clear_idx = syslog_ns->log_next_idx;
>  	}
> -	raw_spin_unlock_irq(&logbuf_lock);
> +	raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
> 
>  	kfree(text);
>  	return len;
> @@ -1102,6 +1091,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
>  	bool clear = false;
>  	static int saved_console_loglevel = -1;
>  	int error;
> +	struct syslog_namespace *syslog_ns = current_syslog_ns();
> 
>  	error = check_syslog_permissions(type, from_file);
>  	if (error)
> @@ -1128,10 +1118,10 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
>  			goto out;
>  		}
>  		error = wait_event_interruptible(log_wait,
> -						 syslog_seq != log_next_seq);
> +			syslog_ns->syslog_seq != syslog_ns->log_next_seq);
>  		if (error)
>  			goto out;
> -		error = syslog_print(buf, len);
> +		error = syslog_print(buf, len, syslog_ns);
>  		break;
>  	/* Read/clear last kernel messages */
>  	case SYSLOG_ACTION_READ_CLEAR:
> @@ -1149,11 +1139,11 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
>  			error = -EFAULT;
>  			goto out;
>  		}
> -		error = syslog_print_all(buf, len, clear);
> +		error = syslog_print_all(buf, len, clear, syslog_ns);
>  		break;
>  	/* Clear ring buffer */
>  	case SYSLOG_ACTION_CLEAR:
> -		syslog_print_all(NULL, 0, true);
> +		syslog_print_all(NULL, 0, true, syslog_ns);
>  		break;
>  	/* Disable logging to console */
>  	case SYSLOG_ACTION_CONSOLE_OFF:
> @@ -1182,13 +1172,13 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
>  		break;
>  	/* Number of chars in the log buffer */
>  	case SYSLOG_ACTION_SIZE_UNREAD:
> -		raw_spin_lock_irq(&logbuf_lock);
> -		if (syslog_seq < log_first_seq) {
> +		raw_spin_lock_irq(&syslog_ns->logbuf_lock);
> +		if (syslog_ns->syslog_seq < syslog_ns->log_first_seq) {
>  			/* messages are gone, move to first one */
> -			syslog_seq = log_first_seq;
> -			syslog_idx = log_first_idx;
> -			syslog_prev = 0;
> -			syslog_partial = 0;
> +			syslog_ns->syslog_seq = syslog_ns->log_first_seq;
> +			syslog_ns->syslog_idx = syslog_ns->log_first_idx;
> +			syslog_ns->syslog_prev = 0;
> +			syslog_ns->syslog_partial = 0;
>  		}
>  		if (from_file) {
>  			/*
> @@ -1196,28 +1186,28 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
>  			 * for pending data, not the size; return the count of
>  			 * records, not the length.
>  			 */
> -			error = log_next_idx - syslog_idx;
> +			error = syslog_ns->log_next_idx - syslog_ns->syslog_idx;
>  		} else {
> -			u64 seq = syslog_seq;
> -			u32 idx = syslog_idx;
> -			enum log_flags prev = syslog_prev;
> +			u64 seq = syslog_ns->syslog_seq;
> +			u32 idx = syslog_ns->syslog_idx;
> +			enum log_flags prev = syslog_ns->syslog_prev;
> 
>  			error = 0;
> -			while (seq < log_next_seq) {
> -				struct log *msg = log_from_idx(idx);
> +			while (seq < syslog_ns->log_next_seq) {
> +				struct log *msg = log_from_idx(idx, syslog_ns);
> 
>  				error += msg_print_text(msg, prev, true, NULL, 0);
> -				idx = log_next(idx);
> +				idx = log_next(idx, syslog_ns);
>  				seq++;
>  				prev = msg->flags;
>  			}
> -			error -= syslog_partial;
> +			error -= syslog_ns->syslog_partial;
>  		}
> -		raw_spin_unlock_irq(&logbuf_lock);
> +		raw_spin_unlock_irq(&syslog_ns->logbuf_lock);
>  		break;
>  	/* Size of the log buffer */
>  	case SYSLOG_ACTION_SIZE_BUFFER:
> -		error = log_buf_len;
> +		error = syslog_ns->log_buf_len;
>  		break;
>  	default:
>  		error = -EINVAL;
> @@ -1282,7 +1272,7 @@ static void call_console_drivers(int level, const char *text, size_t len)
>   * every 10 seconds, to leave time for slow consoles to print a
>   * full oops.
>   */
> -static void zap_locks(void)
> +static void zap_locks(struct syslog_namespace *syslog_ns)
>  {
>  	static unsigned long oops_timestamp;
> 
> @@ -1294,7 +1284,7 @@ static void zap_locks(void)
> 
>  	debug_locks_off();
>  	/* If a crash is occurring, make sure we can't deadlock */
> -	raw_spin_lock_init(&logbuf_lock);
> +	raw_spin_lock_init(&syslog_ns->logbuf_lock);
>  	/* And make sure that we print immediately */
>  	sema_init(&console_sem, 1);
>  }
> @@ -1334,8 +1324,9 @@ static inline int can_use_console(unsigned int cpu)
>   * interrupts disabled. It should return with 'lockbuf_lock'
>   * released but interrupts still disabled.
>   */
> -static int console_trylock_for_printk(unsigned int cpu)
> -	__releases(&logbuf_lock)
> +static int console_trylock_for_printk(unsigned int cpu,
> +			 struct syslog_namespace *syslog_ns)
> +	__releases(&syslog_ns->logbuf_lock)
>  {
>  	int retval = 0, wake = 0;
> 
> @@ -1357,7 +1348,7 @@ static int console_trylock_for_printk(unsigned int cpu)
>  	logbuf_cpu = UINT_MAX;
>  	if (wake)
>  		up(&console_sem);
> -	raw_spin_unlock(&logbuf_lock);
> +	raw_spin_unlock(&syslog_ns->logbuf_lock);
>  	return retval;
>  }
> 
> @@ -1393,7 +1384,7 @@ static struct cont {
>  	bool flushed:1;			/* buffer sealed and committed */
>  } cont;
> 
> -static void cont_flush(enum log_flags flags)
> +static void cont_flush(enum log_flags flags, struct syslog_namespace *syslog_ns)
>  {
>  	if (cont.flushed)
>  		return;
> @@ -1407,7 +1398,7 @@ static void cont_flush(enum log_flags flags)
>  		 * line. LOG_NOCONS suppresses a duplicated output.
>  		 */
>  		log_store(cont.facility, cont.level, flags | LOG_NOCONS,
> -			  cont.ts_nsec, NULL, 0, cont.buf, cont.len);
> +			  cont.ts_nsec, NULL, 0, cont.buf, cont.len, syslog_ns);
>  		cont.flags = flags;
>  		cont.flushed = true;
>  	} else {
> @@ -1416,19 +1407,20 @@ static void cont_flush(enum log_flags flags)
>  		 * just submit it to the store and free the buffer.
>  		 */
>  		log_store(cont.facility, cont.level, flags, 0,
> -			  NULL, 0, cont.buf, cont.len);
> +			  NULL, 0, cont.buf, cont.len, syslog_ns);
>  		cont.len = 0;
>  	}
>  }
> 
> -static bool cont_add(int facility, int level, const char *text, size_t len)
> +static bool cont_add(int facility, int level, const char *text, size_t len,
> +					struct syslog_namespace *syslog_ns)
>  {
>  	if (cont.len && cont.flushed)
>  		return false;
> 
>  	if (cont.len + len > sizeof(cont.buf)) {
>  		/* the line gets too long, split it up in separate records */
> -		cont_flush(LOG_CONT);
> +		cont_flush(LOG_CONT, syslog_ns);
>  		return false;
>  	}
> 
> @@ -1446,7 +1438,7 @@ static bool cont_add(int facility, int level, const char *text, size_t len)
>  	cont.len += len;
> 
>  	if (cont.len > (sizeof(cont.buf) * 80) / 100)
> -		cont_flush(LOG_CONT);
> +		cont_flush(LOG_CONT, syslog_ns);
> 
>  	return true;
>  }
> @@ -1481,7 +1473,8 @@ static size_t cont_print_text(char *text, size_t size)
> 
>  asmlinkage int vprintk_emit(int facility, int level,
>  			    const char *dict, size_t dictlen,
> -			    const char *fmt, va_list args)
> +			    const char *fmt, va_list args,
> +			    struct syslog_namespace *syslog_ns)
>  {
>  	static int recursion_bug;
>  	static char textbuf[LOG_LINE_MAX];
> @@ -1514,11 +1507,11 @@ asmlinkage int vprintk_emit(int facility, int level,
>  			recursion_bug = 1;
>  			goto out_restore_irqs;
>  		}
> -		zap_locks();
> +		zap_locks(syslog_ns);
>  	}
> 
>  	lockdep_off();
> -	raw_spin_lock(&logbuf_lock);
> +	raw_spin_lock(&syslog_ns->logbuf_lock);
>  	logbuf_cpu = this_cpu;
> 
>  	if (recursion_bug) {
> @@ -1529,7 +1522,7 @@ asmlinkage int vprintk_emit(int facility, int level,
>  		printed_len += strlen(recursion_msg);
>  		/* emit KERN_CRIT message */
>  		log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0,
> -			  NULL, 0, recursion_msg, printed_len);
> +			  NULL, 0, recursion_msg, printed_len, syslog_ns);
>  	}
> 
>  	/*
> @@ -1576,12 +1569,12 @@ 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(LOG_NEWLINE);
> +			cont_flush(LOG_NEWLINE, syslog_ns);
> 
>  		/* buffer line if possible, otherwise store it right away */
> -		if (!cont_add(facility, level, text, text_len))
> +		if (!cont_add(facility, level, text, text_len, syslog_ns))
>  			log_store(facility, level, lflags | LOG_CONT, 0,
> -				  dict, dictlen, text, text_len);
> +				  dict, dictlen, text, text_len, syslog_ns);
>  	} else {
>  		bool stored = false;
> 
> @@ -1593,13 +1586,14 @@ 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(LOG_NEWLINE);
> +				stored = cont_add(facility, level, text,
> +							 text_len, syslog_ns);
> +			cont_flush(LOG_NEWLINE, syslog_ns);
>  		}
> 
>  		if (!stored)
>  			log_store(facility, level, lflags, 0,
> -				  dict, dictlen, text, text_len);
> +				  dict, dictlen, text, text_len, syslog_ns);
>  	}
>  	printed_len += text_len;
> 
> @@ -1611,7 +1605,7 @@ asmlinkage int vprintk_emit(int facility, int level,
>  	 * The console_trylock_for_printk() function will release 'logbuf_lock'
>  	 * regardless of whether it actually gets the console semaphore or not.
>  	 */
> -	if (console_trylock_for_printk(this_cpu))
> +	if (console_trylock_for_printk(this_cpu, syslog_ns))
>  		console_unlock();
> 
>  	lockdep_on();
> @@ -1624,7 +1618,8 @@ EXPORT_SYMBOL(vprintk_emit);
> 
>  asmlinkage int vprintk(const char *fmt, va_list args)
>  {
> -	return vprintk_emit(0, -1, NULL, 0, fmt, args);
> +	return vprintk_emit(0, -1, NULL, 0, fmt, args,
> +				current_syslog_ns());
>  }
>  EXPORT_SYMBOL(vprintk);
> 
> @@ -1636,7 +1631,8 @@ asmlinkage int printk_emit(int facility, int level,
>  	int r;
> 
>  	va_start(args, fmt);
> -	r = vprintk_emit(facility, level, dict, dictlen, fmt, args);
> +	r = vprintk_emit(facility, level, dict, dictlen, fmt, args,
> +						current_syslog_ns());
>  	va_end(args);
> 
>  	return r;
> @@ -1678,7 +1674,7 @@ asmlinkage int printk(const char *fmt, ...)
>  	}
>  #endif
>  	va_start(args, fmt);
> -	r = vprintk_emit(0, -1, NULL, 0, fmt, args);
> +	r = vprintk_emit(0, -1, NULL, 0, fmt, args, current_syslog_ns());

Current is meaningless here.  The default should be using init_syslog_ns.

>  	va_end(args);
> 
>  	return r;
> @@ -1981,12 +1977,13 @@ void wake_up_klogd(void)
>  		this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
>  }
> 
> -static void console_cont_flush(char *text, size_t size)
> +static void console_cont_flush(char *text, size_t size,
> +			 struct syslog_namespace *syslog_ns)
>  {
>  	unsigned long flags;
>  	size_t len;
> 
> -	raw_spin_lock_irqsave(&logbuf_lock, flags);
> +	raw_spin_lock_irqsave(&syslog_ns->logbuf_lock, flags);
> 
>  	if (!cont.len)
>  		goto out;
> @@ -1996,18 +1993,131 @@ static void console_cont_flush(char *text, size_t size)
>  	 * busy. The earlier ones need to be printed before this one, we
>  	 * did not flush any fragment so far, so just let it queue up.
>  	 */
> -	if (console_seq < log_next_seq && !cont.cons)
> +	if (syslog_ns->console_seq < syslog_ns->log_next_seq && !cont.cons)
>  		goto out;
> 
>  	len = cont_print_text(text, size);
> -	raw_spin_unlock(&logbuf_lock);
> +	raw_spin_unlock(&syslog_ns->logbuf_lock);
>  	stop_critical_timings();
>  	call_console_drivers(cont.level, text, len);
>  	start_critical_timings();
>  	local_irq_restore(flags);
>  	return;
>  out:
> -	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
> +	raw_spin_unlock_irqrestore(&syslog_ns->logbuf_lock, flags);
> +}
> +
> +/**
> + * syslog_console_unlock - unlock the console system for syslog_namespace
> + *
> + * Releases the console_lock which the caller holds on the console system
> + * and the console driver list.
> + *
> + * While the console_lock was held, console output may have been buffered
> + * by printk().  If this is the case, syslog_console_unlock(); emits
> + * the output prior to releasing the lock.
> + *
> + * If there is output waiting, we wake /dev/kmsg and syslog() users.
> + *
> + * syslog_console_unlock(); may be called from any context.
> + */
> +void syslog_console_unlock(struct syslog_namespace *syslog_ns)
> +{
> +	static char text[LOG_LINE_MAX + PREFIX_MAX];
> +	static u64 seen_seq;
> +	unsigned long flags;
> +	bool wake_klogd = false;
> +	bool retry;
> +
> +	if (console_suspended) {
> +		up(&console_sem);
> +		return;
> +	}
> +
> +	console_may_schedule = 0;
> +
> +	/* flush buffered message fragment immediately to console */
> +	console_cont_flush(text, sizeof(text), syslog_ns);
> +again:
> +	for (;;) {
> +		struct log *msg;
> +		size_t len;
> +		int level;
> +
> +		raw_spin_lock_irqsave(&syslog_ns->logbuf_lock, flags);
> +		if (seen_seq != syslog_ns->log_next_seq) {
> +			wake_klogd = true;
> +			seen_seq = syslog_ns->log_next_seq;
> +		}
> +
> +		if (syslog_ns->console_seq < syslog_ns->log_first_seq) {
> +			/* messages are gone, move to first one */
> +			syslog_ns->console_seq = syslog_ns->log_first_seq;
> +			syslog_ns->console_idx = syslog_ns->log_first_idx;
> +			console_prev = 0;
> +		}
> +skip:
> +		if (syslog_ns->console_seq == syslog_ns->log_next_seq)
> +			break;
> +
> +		msg = log_from_idx(syslog_ns->console_idx, syslog_ns);
> +		if (msg->flags & LOG_NOCONS) {
> +			/*
> +			 * Skip record we have buffered and already printed
> +			 * directly to the console when we received it.
> +			 */
> +			syslog_ns->console_idx =
> +				log_next(syslog_ns->console_idx, syslog_ns);
> +			syslog_ns->console_seq++;
> +			/*
> +			 * We will get here again when we register a new
> +			 * CON_PRINTBUFFER console. Clear the flag so we
> +			 * will properly dump everything later.
> +			 */
> +			msg->flags &= ~LOG_NOCONS;
> +			console_prev = msg->flags;
> +			goto skip;
> +		}
> +
> +		level = msg->level;
> +		len = msg_print_text(msg, console_prev, false,
> +				     text, sizeof(text));
> +		syslog_ns->console_idx =
> +			 log_next(syslog_ns->console_idx, syslog_ns);
> +		syslog_ns->console_seq++;
> +		console_prev = msg->flags;
> +		raw_spin_unlock(&syslog_ns->logbuf_lock);
> +
> +		stop_critical_timings();	/* don't trace print latency */
> +		call_console_drivers(level, text, len);
> +		start_critical_timings();
> +		local_irq_restore(flags);
> +	}
> +	console_locked = 0;
> +
> +	/* Release the exclusive_console once it is used */
> +	if (unlikely(exclusive_console))
> +		exclusive_console = NULL;
> +
> +	raw_spin_unlock(&syslog_ns->logbuf_lock);
> +
> +	up(&console_sem);
> +
> +	/*
> +	 * Someone could have filled up the buffer again, so re-check if there's
> +	 * something to flush. In case we cannot trylock the console_sem again,
> +	 * there's a new owner and the console_unlock() from them will do the
> +	 * flush, no worries.
> +	 */
> +	raw_spin_lock(&syslog_ns->logbuf_lock);
> +	retry = syslog_ns->console_seq != syslog_ns->log_next_seq;
> +	raw_spin_unlock_irqrestore(&syslog_ns->logbuf_lock, flags);
> +
> +	if (retry && console_trylock())
> +		goto again;
> +
> +	if (wake_klogd)
> +		wake_up_klogd();
>  }
> 
>  /**
> @@ -2027,6 +2137,7 @@ out:
>  void console_unlock(void)
>  {
>  	static char text[LOG_LINE_MAX + PREFIX_MAX];
> +	struct syslog_namespace *syslog_ns = current_syslog_ns();
>  	static u64 seen_seq;
>  	unsigned long flags;
>  	bool wake_klogd = false;
> @@ -2040,37 +2151,38 @@ void console_unlock(void)
>  	console_may_schedule = 0;
> 
>  	/* flush buffered message fragment immediately to console */
> -	console_cont_flush(text, sizeof(text));
> +	console_cont_flush(text, sizeof(text), syslog_ns);
>  again:
>  	for (;;) {
>  		struct log *msg;
>  		size_t len;
>  		int level;
> 
> -		raw_spin_lock_irqsave(&logbuf_lock, flags);
> -		if (seen_seq != log_next_seq) {
> +		raw_spin_lock_irqsave(&syslog_ns->logbuf_lock, flags);
> +		if (seen_seq != syslog_ns->log_next_seq) {
>  			wake_klogd = true;
> -			seen_seq = log_next_seq;
> +			seen_seq = syslog_ns->log_next_seq;
>  		}
> 
> -		if (console_seq < log_first_seq) {
> +		if (syslog_ns->console_seq < syslog_ns->log_first_seq) {
>  			/* messages are gone, move to first one */
> -			console_seq = log_first_seq;
> -			console_idx = log_first_idx;
> +			syslog_ns->console_seq = syslog_ns->log_first_seq;
> +			syslog_ns->console_idx = syslog_ns->log_first_idx;
>  			console_prev = 0;
>  		}
>  skip:
> -		if (console_seq == log_next_seq)
> +		if (syslog_ns->console_seq == syslog_ns->log_next_seq)
>  			break;
> 
> -		msg = log_from_idx(console_idx);
> +		msg = log_from_idx(syslog_ns->console_idx, syslog_ns);
>  		if (msg->flags & LOG_NOCONS) {
>  			/*
>  			 * Skip record we have buffered and already printed
>  			 * directly to the console when we received it.
>  			 */
> -			console_idx = log_next(console_idx);
> -			console_seq++;
> +			syslog_ns->console_idx =
> +				 log_next(syslog_ns->console_idx, syslog_ns);
> +			syslog_ns->console_seq++;
>  			/*
>  			 * We will get here again when we register a new
>  			 * CON_PRINTBUFFER console. Clear the flag so we
> @@ -2084,10 +2196,11 @@ skip:
>  		level = msg->level;
>  		len = msg_print_text(msg, console_prev, false,
>  				     text, sizeof(text));
> -		console_idx = log_next(console_idx);
> -		console_seq++;
> +		syslog_ns->console_idx =
> +			 log_next(syslog_ns->console_idx, syslog_ns);
> +		syslog_ns->console_seq++;
>  		console_prev = msg->flags;
> -		raw_spin_unlock(&logbuf_lock);
> +		raw_spin_unlock(&syslog_ns->logbuf_lock);
> 
>  		stop_critical_timings();	/* don't trace print latency */
>  		call_console_drivers(level, text, len);
> @@ -2100,7 +2213,7 @@ skip:
>  	if (unlikely(exclusive_console))
>  		exclusive_console = NULL;
> 
> -	raw_spin_unlock(&logbuf_lock);
> +	raw_spin_unlock(&syslog_ns->logbuf_lock);
> 
>  	up(&console_sem);
> 
> @@ -2110,9 +2223,9 @@ skip:
>  	 * there's a new owner and the console_unlock() from them will do the
>  	 * flush, no worries.
>  	 */
> -	raw_spin_lock(&logbuf_lock);
> -	retry = console_seq != log_next_seq;
> -	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
> +	raw_spin_lock(&syslog_ns->logbuf_lock);
> +	retry = syslog_ns->console_seq != syslog_ns->log_next_seq;
> +	raw_spin_unlock_irqrestore(&syslog_ns->logbuf_lock, flags);
> 
>  	if (retry && console_trylock())
>  		goto again;
> @@ -2237,6 +2350,7 @@ void register_console(struct console *newcon)
>  	int i;
>  	unsigned long flags;
>  	struct console *bcon = NULL;
> +	struct syslog_namespace *syslog_ns = &init_syslog_ns;
> 
>  	/*
>  	 * before we register a new CON_BOOT console, make sure we don't
> @@ -2346,11 +2460,11 @@ void register_console(struct console *newcon)
>  		 * console_unlock(); will print out the buffered messages
>  		 * for us.
>  		 */
> -		raw_spin_lock_irqsave(&logbuf_lock, flags);
> -		console_seq = syslog_seq;
> -		console_idx = syslog_idx;
> -		console_prev = syslog_prev;
> -		raw_spin_unlock_irqrestore(&logbuf_lock, flags);
> +		raw_spin_lock_irqsave(&syslog_ns->logbuf_lock, flags);
> +		syslog_ns->console_seq = syslog_ns->syslog_seq;
> +		syslog_ns->console_idx = syslog_ns->syslog_idx;
> +		console_prev = syslog_ns->syslog_prev;
> +		raw_spin_unlock_irqrestore(&syslog_ns->logbuf_lock, flags);
>  		/*
>  		 * We're about to replay the log buffer.  Only do this to the
>  		 * just-registered console to avoid excessive message spam to
> @@ -2573,6 +2687,7 @@ void kmsg_dump(enum kmsg_dump_reason reason)
>  {
>  	struct kmsg_dumper *dumper;
>  	unsigned long flags;
> +	struct syslog_namespace *syslog_ns = &init_syslog_ns;
> 
>  	if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
>  		return;
> @@ -2585,12 +2700,12 @@ void kmsg_dump(enum kmsg_dump_reason reason)
>  		/* initialize iterator with data about the stored records */
>  		dumper->active = true;
> 
> -		raw_spin_lock_irqsave(&logbuf_lock, flags);
> -		dumper->cur_seq = clear_seq;
> -		dumper->cur_idx = clear_idx;
> -		dumper->next_seq = log_next_seq;
> -		dumper->next_idx = log_next_idx;
> -		raw_spin_unlock_irqrestore(&logbuf_lock, flags);
> +		raw_spin_lock_irqsave(&syslog_ns->logbuf_lock, flags);
> +		dumper->cur_seq = syslog_ns->clear_seq;
> +		dumper->cur_idx = syslog_ns->clear_idx;
> +		dumper->next_seq = syslog_ns->log_next_seq;
> +		dumper->next_idx = syslog_ns->log_next_idx;
> +		raw_spin_unlock_irqrestore(&syslog_ns->logbuf_lock, flags);
> 
>  		/* invoke dumper which will iterate over records */
>  		dumper->dump(dumper, reason);
> @@ -2626,24 +2741,25 @@ bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog,
>  	struct log *msg;
>  	size_t l = 0;
>  	bool ret = false;
> +	struct syslog_namespace *syslog_ns = &init_syslog_ns;
> 
>  	if (!dumper->active)
>  		goto out;
> 
> -	if (dumper->cur_seq < log_first_seq) {
> +	if (dumper->cur_seq < syslog_ns->log_first_seq) {
>  		/* messages are gone, move to first available one */
> -		dumper->cur_seq = log_first_seq;
> -		dumper->cur_idx = log_first_idx;
> +		dumper->cur_seq = syslog_ns->log_first_seq;
> +		dumper->cur_idx = syslog_ns->log_first_idx;
>  	}
> 
>  	/* last entry */
> -	if (dumper->cur_seq >= log_next_seq)
> +	if (dumper->cur_seq >= syslog_ns->log_next_seq)
>  		goto out;
> 
> -	msg = log_from_idx(dumper->cur_idx);
> +	msg = log_from_idx(dumper->cur_idx, syslog_ns);
>  	l = msg_print_text(msg, 0, syslog, line, size);
> 
> -	dumper->cur_idx = log_next(dumper->cur_idx);
> +	dumper->cur_idx = log_next(dumper->cur_idx, syslog_ns);
>  	dumper->cur_seq++;
>  	ret = true;
>  out:
> @@ -2674,10 +2790,12 @@ bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
>  {
>  	unsigned long flags;
>  	bool ret;
> +	struct syslog_namespace *syslog_ns = &init_syslog_ns;
> +
> +	raw_spin_lock_irqsave(&syslog_ns->logbuf_lock, flags);
> 
> -	raw_spin_lock_irqsave(&logbuf_lock, flags);
>  	ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
> -	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
> +	raw_spin_unlock_irqrestore(&syslog_ns->logbuf_lock, flags);
> 
>  	return ret;
>  }
> @@ -2713,20 +2831,21 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
>  	enum log_flags prev;
>  	size_t l = 0;
>  	bool ret = false;
> +	struct syslog_namespace *syslog_ns = &init_syslog_ns;
> 
>  	if (!dumper->active)
>  		goto out;
> 
> -	raw_spin_lock_irqsave(&logbuf_lock, flags);
> -	if (dumper->cur_seq < log_first_seq) {
> +	raw_spin_lock_irqsave(&syslog_ns->logbuf_lock, flags);
> +	if (dumper->cur_seq < syslog_ns->log_first_seq) {
>  		/* messages are gone, move to first available one */
> -		dumper->cur_seq = log_first_seq;
> -		dumper->cur_idx = log_first_idx;
> +		dumper->cur_seq = syslog_ns->log_first_seq;
> +		dumper->cur_idx = syslog_ns->log_first_idx;
>  	}
> 
>  	/* last entry */
>  	if (dumper->cur_seq >= dumper->next_seq) {
> -		raw_spin_unlock_irqrestore(&logbuf_lock, flags);
> +		raw_spin_unlock_irqrestore(&syslog_ns->logbuf_lock, flags);
>  		goto out;
>  	}
> 
> @@ -2735,10 +2854,10 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
>  	idx = dumper->cur_idx;
>  	prev = 0;
>  	while (seq < dumper->next_seq) {
> -		struct log *msg = log_from_idx(idx);
> +		struct log *msg = log_from_idx(idx, syslog_ns);
> 
>  		l += msg_print_text(msg, prev, true, NULL, 0);
> -		idx = log_next(idx);
> +		idx = log_next(idx, syslog_ns);
>  		seq++;
>  		prev = msg->flags;
>  	}
> @@ -2748,10 +2867,10 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
>  	idx = dumper->cur_idx;
>  	prev = 0;
>  	while (l > size && seq < dumper->next_seq) {
> -		struct log *msg = log_from_idx(idx);
> +		struct log *msg = log_from_idx(idx, syslog_ns);
> 
>  		l -= msg_print_text(msg, prev, true, NULL, 0);
> -		idx = log_next(idx);
> +		idx = log_next(idx, syslog_ns);
>  		seq++;
>  		prev = msg->flags;
>  	}
> @@ -2763,10 +2882,10 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
>  	l = 0;
>  	prev = 0;
>  	while (seq < dumper->next_seq) {
> -		struct log *msg = log_from_idx(idx);
> +		struct log *msg = log_from_idx(idx, syslog_ns);
> 
>  		l += msg_print_text(msg, prev, syslog, buf + l, size - l);
> -		idx = log_next(idx);
> +		idx = log_next(idx, syslog_ns);
>  		seq++;
>  		prev = msg->flags;
>  	}
> @@ -2774,7 +2893,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
>  	dumper->next_seq = next_seq;
>  	dumper->next_idx = next_idx;
>  	ret = true;
> -	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
> +	raw_spin_unlock_irqrestore(&syslog_ns->logbuf_lock, flags);
>  out:
>  	if (len)
>  		*len = l;
> @@ -2794,10 +2913,12 @@ EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
>   */
>  void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
>  {
> -	dumper->cur_seq = clear_seq;
> -	dumper->cur_idx = clear_idx;
> -	dumper->next_seq = log_next_seq;
> -	dumper->next_idx = log_next_idx;
> +	struct syslog_namespace *syslog_ns = &init_syslog_ns;
> +
> +	dumper->cur_seq = syslog_ns->clear_seq;
> +	dumper->cur_idx = syslog_ns->clear_idx;
> +	dumper->next_seq = syslog_ns->log_next_seq;
> +	dumper->next_idx = syslog_ns->log_next_idx;
>  }
> 
>  /**
> @@ -2811,10 +2932,12 @@ void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
>  void kmsg_dump_rewind(struct kmsg_dumper *dumper)
>  {
>  	unsigned long flags;
> +	struct syslog_namespace *syslog_ns = &init_syslog_ns;
> +
> +	raw_spin_lock_irqsave(&syslog_ns->logbuf_lock, flags);
> 
> -	raw_spin_lock_irqsave(&logbuf_lock, flags);
>  	kmsg_dump_rewind_nolock(dumper);
> -	raw_spin_unlock_irqrestore(&logbuf_lock, flags);
> +	raw_spin_unlock_irqrestore(&syslog_ns->logbuf_lock, flags);
>  }
>  EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
>  #endif
> -- 
> 1.7.1
> 
> _______________________________________________
> Containers mailing list
> Containers@...ts.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/containers
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