printk: convert the rest to printk-safe
This patch converts the rest of logbuf users (which are out of printk recursion case, but can deadlock in printk). To make printk-safe usage easier the patch introduces 4 helper macros: - logbuf_lock_irq()/logbuf_unlock_irq() lock/unlock the logbuf lock and disable/enable local IRQ - logbuf_lock_irqsave(flags)/logbuf_unlock_irqrestore(flags) lock/unlock the logbuf lock and saves/restores local IRQ state Link: http://lkml.kernel.org/r/20161227141611.940-9-sergey.senozhatsky@gmail.com Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Cc: Tejun Heo <tj@kernel.org> Cc: Calvin Owens <calvinowens@fb.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Peter Hurley <peter@hurleysoftware.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
This commit is contained in:
parent
8b1742c9c2
commit
de6fcbdb68
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@ -370,6 +370,34 @@ __packed __aligned(4)
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*/
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*/
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DEFINE_RAW_SPINLOCK(logbuf_lock);
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DEFINE_RAW_SPINLOCK(logbuf_lock);
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/*
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* Helper macros to lock/unlock logbuf_lock and switch between
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* printk-safe/unsafe modes.
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*/
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#define logbuf_lock_irq() \
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do { \
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printk_safe_enter_irq(); \
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raw_spin_lock(&logbuf_lock); \
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} while (0)
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#define logbuf_unlock_irq() \
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do { \
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raw_spin_unlock(&logbuf_lock); \
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printk_safe_exit_irq(); \
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} while (0)
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#define logbuf_lock_irqsave(flags) \
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do { \
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printk_safe_enter_irqsave(flags); \
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raw_spin_lock(&logbuf_lock); \
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} while (0)
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#define logbuf_unlock_irqrestore(flags) \
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do { \
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raw_spin_unlock(&logbuf_lock); \
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printk_safe_exit_irqrestore(flags); \
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} while (0)
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#ifdef CONFIG_PRINTK
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#ifdef CONFIG_PRINTK
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DECLARE_WAIT_QUEUE_HEAD(log_wait);
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DECLARE_WAIT_QUEUE_HEAD(log_wait);
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/* the next printk record to read by syslog(READ) or /proc/kmsg */
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/* the next printk record to read by syslog(READ) or /proc/kmsg */
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@ -801,20 +829,21 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
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ret = mutex_lock_interruptible(&user->lock);
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ret = mutex_lock_interruptible(&user->lock);
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if (ret)
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if (ret)
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return ret;
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return ret;
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raw_spin_lock_irq(&logbuf_lock);
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logbuf_lock_irq();
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while (user->seq == log_next_seq) {
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while (user->seq == log_next_seq) {
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if (file->f_flags & O_NONBLOCK) {
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if (file->f_flags & O_NONBLOCK) {
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ret = -EAGAIN;
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ret = -EAGAIN;
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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goto out;
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goto out;
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}
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}
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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ret = wait_event_interruptible(log_wait,
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ret = wait_event_interruptible(log_wait,
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user->seq != log_next_seq);
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user->seq != log_next_seq);
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if (ret)
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if (ret)
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goto out;
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goto out;
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raw_spin_lock_irq(&logbuf_lock);
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logbuf_lock_irq();
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}
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}
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if (user->seq < log_first_seq) {
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if (user->seq < log_first_seq) {
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@ -822,7 +851,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
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user->idx = log_first_idx;
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user->idx = log_first_idx;
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user->seq = log_first_seq;
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user->seq = log_first_seq;
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ret = -EPIPE;
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ret = -EPIPE;
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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goto out;
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goto out;
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}
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}
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@ -835,7 +864,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
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user->idx = log_next(user->idx);
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user->idx = log_next(user->idx);
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user->seq++;
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user->seq++;
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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if (len > count) {
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if (len > count) {
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ret = -EINVAL;
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ret = -EINVAL;
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@ -862,7 +891,7 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
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if (offset)
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if (offset)
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return -ESPIPE;
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return -ESPIPE;
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raw_spin_lock_irq(&logbuf_lock);
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logbuf_lock_irq();
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switch (whence) {
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switch (whence) {
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case SEEK_SET:
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case SEEK_SET:
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/* the first record */
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/* the first record */
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@ -886,7 +915,7 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
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default:
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default:
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ret = -EINVAL;
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ret = -EINVAL;
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}
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}
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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return ret;
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return ret;
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}
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}
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@ -900,7 +929,7 @@ static unsigned int devkmsg_poll(struct file *file, poll_table *wait)
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poll_wait(file, &log_wait, wait);
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poll_wait(file, &log_wait, wait);
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raw_spin_lock_irq(&logbuf_lock);
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logbuf_lock_irq();
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if (user->seq < log_next_seq) {
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if (user->seq < log_next_seq) {
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/* return error when data has vanished underneath us */
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/* return error when data has vanished underneath us */
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if (user->seq < log_first_seq)
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if (user->seq < log_first_seq)
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@ -908,7 +937,7 @@ static unsigned int devkmsg_poll(struct file *file, poll_table *wait)
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else
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else
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ret = POLLIN|POLLRDNORM;
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ret = POLLIN|POLLRDNORM;
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}
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}
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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return ret;
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return ret;
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}
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}
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@ -938,10 +967,10 @@ static int devkmsg_open(struct inode *inode, struct file *file)
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mutex_init(&user->lock);
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mutex_init(&user->lock);
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raw_spin_lock_irq(&logbuf_lock);
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logbuf_lock_irq();
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user->idx = log_first_idx;
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user->idx = log_first_idx;
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user->seq = log_first_seq;
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user->seq = log_first_seq;
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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file->private_data = user;
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file->private_data = user;
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return 0;
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return 0;
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@ -1083,13 +1112,13 @@ void __init setup_log_buf(int early)
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return;
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return;
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}
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}
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raw_spin_lock_irqsave(&logbuf_lock, flags);
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logbuf_lock_irqsave(flags);
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log_buf_len = new_log_buf_len;
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log_buf_len = new_log_buf_len;
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log_buf = new_log_buf;
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log_buf = new_log_buf;
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new_log_buf_len = 0;
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new_log_buf_len = 0;
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free = __LOG_BUF_LEN - log_next_idx;
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free = __LOG_BUF_LEN - log_next_idx;
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memcpy(log_buf, __log_buf, __LOG_BUF_LEN);
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memcpy(log_buf, __log_buf, __LOG_BUF_LEN);
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raw_spin_unlock_irqrestore(&logbuf_lock, flags);
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logbuf_unlock_irqrestore(flags);
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pr_info("log_buf_len: %d bytes\n", log_buf_len);
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pr_info("log_buf_len: %d bytes\n", log_buf_len);
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pr_info("early log buf free: %d(%d%%)\n",
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pr_info("early log buf free: %d(%d%%)\n",
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@ -1267,7 +1296,7 @@ static int syslog_print(char __user *buf, int size)
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size_t n;
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size_t n;
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size_t skip;
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size_t skip;
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raw_spin_lock_irq(&logbuf_lock);
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logbuf_lock_irq();
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if (syslog_seq < log_first_seq) {
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if (syslog_seq < log_first_seq) {
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/* messages are gone, move to first one */
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/* messages are gone, move to first one */
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syslog_seq = log_first_seq;
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syslog_seq = log_first_seq;
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@ -1275,7 +1304,7 @@ static int syslog_print(char __user *buf, int size)
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syslog_partial = 0;
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syslog_partial = 0;
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}
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}
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if (syslog_seq == log_next_seq) {
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if (syslog_seq == log_next_seq) {
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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break;
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break;
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}
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}
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@ -1294,7 +1323,7 @@ static int syslog_print(char __user *buf, int size)
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syslog_partial += n;
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syslog_partial += n;
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} else
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} else
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n = 0;
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n = 0;
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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if (!n)
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if (!n)
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break;
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break;
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@ -1323,7 +1352,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
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if (!text)
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if (!text)
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return -ENOMEM;
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return -ENOMEM;
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raw_spin_lock_irq(&logbuf_lock);
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logbuf_lock_irq();
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if (buf) {
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if (buf) {
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u64 next_seq;
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u64 next_seq;
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u64 seq;
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u64 seq;
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@ -1371,12 +1400,12 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
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idx = log_next(idx);
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idx = log_next(idx);
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seq++;
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seq++;
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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if (copy_to_user(buf + len, text, textlen))
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if (copy_to_user(buf + len, text, textlen))
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len = -EFAULT;
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len = -EFAULT;
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else
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else
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len += textlen;
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len += textlen;
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raw_spin_lock_irq(&logbuf_lock);
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logbuf_lock_irq();
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if (seq < log_first_seq) {
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if (seq < log_first_seq) {
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/* messages are gone, move to next one */
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/* messages are gone, move to next one */
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@ -1390,7 +1419,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
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clear_seq = log_next_seq;
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clear_seq = log_next_seq;
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clear_idx = log_next_idx;
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clear_idx = log_next_idx;
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}
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}
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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kfree(text);
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kfree(text);
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return len;
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return len;
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@ -1477,7 +1506,7 @@ int do_syslog(int type, char __user *buf, int len, int source)
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break;
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break;
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/* Number of chars in the log buffer */
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/* Number of chars in the log buffer */
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case SYSLOG_ACTION_SIZE_UNREAD:
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case SYSLOG_ACTION_SIZE_UNREAD:
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raw_spin_lock_irq(&logbuf_lock);
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logbuf_lock_irq();
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if (syslog_seq < log_first_seq) {
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if (syslog_seq < log_first_seq) {
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/* messages are gone, move to first one */
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/* messages are gone, move to first one */
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syslog_seq = log_first_seq;
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syslog_seq = log_first_seq;
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@ -1505,7 +1534,7 @@ int do_syslog(int type, char __user *buf, int len, int source)
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}
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}
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error -= syslog_partial;
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error -= syslog_partial;
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}
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}
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raw_spin_unlock_irq(&logbuf_lock);
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logbuf_unlock_irq();
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break;
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break;
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/* Size of the log buffer */
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/* Size of the log buffer */
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case SYSLOG_ACTION_SIZE_BUFFER:
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case SYSLOG_ACTION_SIZE_BUFFER:
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@ -1682,9 +1711,8 @@ asmlinkage int vprintk_emit(int facility, int level,
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boot_delay_msec(level);
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boot_delay_msec(level);
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printk_delay();
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printk_delay();
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printk_safe_enter_irqsave(flags);
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/* This stops the holder of console_sem just where we want him */
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/* This stops the holder of console_sem just where we want him */
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raw_spin_lock(&logbuf_lock);
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logbuf_lock_irqsave(flags);
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/*
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/*
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* The printf needs to come first; we need the syslog
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* The printf needs to come first; we need the syslog
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* prefix which might be passed-in as a parameter.
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* prefix which might be passed-in as a parameter.
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@ -1727,8 +1755,7 @@ asmlinkage int vprintk_emit(int facility, int level,
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printed_len += log_output(facility, level, lflags, dict, dictlen, text, text_len);
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printed_len += log_output(facility, level, lflags, dict, dictlen, text, text_len);
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raw_spin_unlock(&logbuf_lock);
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logbuf_unlock_irqrestore(flags);
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printk_safe_exit_irqrestore(flags);
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/* If called from the scheduler, we can not call up(). */
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/* If called from the scheduler, we can not call up(). */
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if (!in_sched) {
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if (!in_sched) {
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@ -2501,10 +2528,10 @@ void register_console(struct console *newcon)
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* console_unlock(); will print out the buffered messages
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* console_unlock(); will print out the buffered messages
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* for us.
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* for us.
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*/
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*/
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raw_spin_lock_irqsave(&logbuf_lock, flags);
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logbuf_lock_irqsave(flags);
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console_seq = syslog_seq;
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console_seq = syslog_seq;
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console_idx = syslog_idx;
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console_idx = syslog_idx;
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raw_spin_unlock_irqrestore(&logbuf_lock, flags);
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logbuf_unlock_irqrestore(flags);
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/*
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/*
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* We're about to replay the log buffer. Only do this to the
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* We're about to replay the log buffer. Only do this to the
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* just-registered console to avoid excessive message spam to
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* just-registered console to avoid excessive message spam to
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@ -2803,12 +2830,12 @@ void kmsg_dump(enum kmsg_dump_reason reason)
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/* initialize iterator with data about the stored records */
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/* initialize iterator with data about the stored records */
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dumper->active = true;
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dumper->active = true;
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raw_spin_lock_irqsave(&logbuf_lock, flags);
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logbuf_lock_irqsave(flags);
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dumper->cur_seq = clear_seq;
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dumper->cur_seq = clear_seq;
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dumper->cur_idx = clear_idx;
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dumper->cur_idx = clear_idx;
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dumper->next_seq = log_next_seq;
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dumper->next_seq = log_next_seq;
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dumper->next_idx = log_next_idx;
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dumper->next_idx = log_next_idx;
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raw_spin_unlock_irqrestore(&logbuf_lock, flags);
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logbuf_unlock_irqrestore(flags);
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/* invoke dumper which will iterate over records */
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/* invoke dumper which will iterate over records */
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dumper->dump(dumper, reason);
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dumper->dump(dumper, reason);
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@ -2893,9 +2920,9 @@ bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
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unsigned long flags;
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unsigned long flags;
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bool ret;
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bool ret;
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raw_spin_lock_irqsave(&logbuf_lock, flags);
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logbuf_lock_irqsave(flags);
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ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
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ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
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raw_spin_unlock_irqrestore(&logbuf_lock, flags);
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logbuf_unlock_irqrestore(flags);
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return ret;
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return ret;
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}
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}
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@ -2934,7 +2961,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
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if (!dumper->active)
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if (!dumper->active)
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goto out;
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goto out;
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raw_spin_lock_irqsave(&logbuf_lock, flags);
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logbuf_lock_irqsave(flags);
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if (dumper->cur_seq < log_first_seq) {
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if (dumper->cur_seq < log_first_seq) {
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/* messages are gone, move to first available one */
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/* messages are gone, move to first available one */
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dumper->cur_seq = log_first_seq;
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dumper->cur_seq = log_first_seq;
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@ -2943,7 +2970,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
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/* last entry */
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/* last entry */
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if (dumper->cur_seq >= dumper->next_seq) {
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if (dumper->cur_seq >= dumper->next_seq) {
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raw_spin_unlock_irqrestore(&logbuf_lock, flags);
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logbuf_unlock_irqrestore(flags);
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goto out;
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goto out;
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}
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}
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@ -2985,7 +3012,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
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dumper->next_seq = next_seq;
|
dumper->next_seq = next_seq;
|
||||||
dumper->next_idx = next_idx;
|
dumper->next_idx = next_idx;
|
||||||
ret = true;
|
ret = true;
|
||||||
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
|
logbuf_unlock_irqrestore(flags);
|
||||||
out:
|
out:
|
||||||
if (len)
|
if (len)
|
||||||
*len = l;
|
*len = l;
|
||||||
|
@ -3023,9 +3050,9 @@ void kmsg_dump_rewind(struct kmsg_dumper *dumper)
|
||||||
{
|
{
|
||||||
unsigned long flags;
|
unsigned long flags;
|
||||||
|
|
||||||
raw_spin_lock_irqsave(&logbuf_lock, flags);
|
logbuf_lock_irqsave(flags);
|
||||||
kmsg_dump_rewind_nolock(dumper);
|
kmsg_dump_rewind_nolock(dumper);
|
||||||
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
|
logbuf_unlock_irqrestore(flags);
|
||||||
}
|
}
|
||||||
EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
|
EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
|
||||||
|
|
||||||
|
|
Loading…
Reference in New Issue