1 files changed, 11 insertions, 0 deletions

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index f6fe60d725dd..170d3a8040f4 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -783,6 +783,8 @@ static ssize_t devkmsg_write(struct kiocb *iocb, struct iov_iter *from)
         return ret;
 }
 
+static void cont_flush(void);
+
 static ssize_t devkmsg_read(struct file *file, char __user *buf,
                             size_t count, loff_t *ppos)
 {
@@ -798,6 +800,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf,
         if (ret)
                 return ret;
         raw_spin_lock_irq(&logbuf_lock);
+        cont_flush();
         while (user->seq == log_next_seq) {
                 if (file->f_flags & O_NONBLOCK) {
                         ret = -EAGAIN;
@@ -860,6 +863,7 @@ static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence)
                 return -ESPIPE;
 
         raw_spin_lock_irq(&logbuf_lock);
+        cont_flush();
         switch (whence) {
         case SEEK_SET:
                 /* the first record */
@@ -898,6 +902,7 @@ static unsigned int devkmsg_poll(struct file *file, poll_table *wait)
         poll_wait(file, &log_wait, wait);
 
         raw_spin_lock_irq(&logbuf_lock);
+        cont_flush();
         if (user->seq < log_next_seq) {
                 /* return error when data has vanished underneath us */
                 if (user->seq < log_first_seq)
@@ -1284,6 +1289,7 @@ static int syslog_print(char __user *buf, int size)
                 size_t skip;
 
                 raw_spin_lock_irq(&logbuf_lock);
+                cont_flush();
                 if (syslog_seq < log_first_seq) {
                         /* messages are gone, move to first one */
                         syslog_seq = log_first_seq;
@@ -1343,6 +1349,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
                 return -ENOMEM;
 
         raw_spin_lock_irq(&logbuf_lock);
+        cont_flush();
         if (buf) {
                 u64 next_seq;
                 u64 seq;
@@ -1504,6 +1511,7 @@ int do_syslog(int type, char __user *buf, int len, int source)
         /* Number of chars in the log buffer */
         case SYSLOG_ACTION_SIZE_UNREAD:
                 raw_spin_lock_irq(&logbuf_lock);
+                cont_flush();
                 if (syslog_seq < log_first_seq) {
                         /* messages are gone, move to first one */
                         syslog_seq = log_first_seq;
@@ -3016,6 +3024,7 @@ void kmsg_dump(enum kmsg_dump_reason reason)
                 dumper->active = true;
 
                 raw_spin_lock_irqsave(&logbuf_lock, flags);
+                cont_flush();
                 dumper->cur_seq = clear_seq;
                 dumper->cur_idx = clear_idx;
                 dumper->next_seq = log_next_seq;
@@ -3106,6 +3115,7 @@ bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
         bool ret;
 
         raw_spin_lock_irqsave(&logbuf_lock, flags);
+        cont_flush();
         ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
         raw_spin_unlock_irqrestore(&logbuf_lock, flags);
 
@@ -3148,6 +3158,7 @@ bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
                 goto out;
 
         raw_spin_lock_irqsave(&logbuf_lock, flags);
+        cont_flush();
         if (dumper->cur_seq < log_first_seq) {
                 /* messages are gone, move to first available one */
                 dumper->cur_seq = log_first_seq;