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-rw-r--r--kernel/printk.c26
1 files changed, 24 insertions, 2 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index e3602d0755b0..5052b5497c67 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -32,6 +32,7 @@
#include <linux/security.h>
#include <linux/bootmem.h>
#include <linux/syscalls.h>
+#include <linux/kexec.h>
#include <asm/uaccess.h>
@@ -135,6 +136,24 @@ static char *log_buf = __log_buf;
static int log_buf_len = __LOG_BUF_LEN;
static unsigned logged_chars; /* Number of chars produced since last read+clear operation */
+#ifdef CONFIG_KEXEC
+/*
+ * This appends the listed symbols to /proc/vmcoreinfo
+ *
+ * /proc/vmcoreinfo is used by various utiilties, like crash and makedumpfile to
+ * obtain access to symbols that are otherwise very difficult to locate. These
+ * symbols are specifically used so that utilities can access and extract the
+ * dmesg log from a vmcore file after a crash.
+ */
+void log_buf_kexec_setup(void)
+{
+ VMCOREINFO_SYMBOL(log_buf);
+ VMCOREINFO_SYMBOL(log_end);
+ VMCOREINFO_SYMBOL(log_buf_len);
+ VMCOREINFO_SYMBOL(logged_chars);
+}
+#endif
+
static int __init log_buf_len_setup(char *str)
{
unsigned size = memparse(str, &str);
@@ -1292,8 +1311,11 @@ EXPORT_SYMBOL(printk_ratelimit);
bool printk_timed_ratelimit(unsigned long *caller_jiffies,
unsigned int interval_msecs)
{
- if (*caller_jiffies == 0 || time_after(jiffies, *caller_jiffies)) {
- *caller_jiffies = jiffies + msecs_to_jiffies(interval_msecs);
+ if (*caller_jiffies == 0
+ || !time_in_range(jiffies, *caller_jiffies,
+ *caller_jiffies
+ + msecs_to_jiffies(interval_msecs))) {
+ *caller_jiffies = jiffies;
return true;
}
return false;
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