`recursion_bug' occupies 4 bytes to just tell us there was a recent
recursion bug (basically 'bool'). Make it a bit more informative and
keep in `recursion_bug' smp_processor_id of the CPU (the most recent
one) that has caused a recursive printk bug. For instance, the error
message will change from
BUG: recent printk recursion!
to
BUG: recent printk recursion on CPU5!
Rename `recursion_bug' to `recursion_bug_cpu'.
Signed-off-by: Sergey Senozhatsky <[email protected]>
---
kernel/printk/printk.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 1fc89ba..a578653 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1662,7 +1662,7 @@ asmlinkage int vprintk_emit(int facility, int level,
const char *dict, size_t dictlen,
const char *fmt, va_list args)
{
- static int recursion_bug;
+ static int recursion_bug_cpu = -1;
static char textbuf[LOG_LINE_MAX];
char *text = textbuf;
size_t text_len = 0;
@@ -1699,7 +1699,7 @@ asmlinkage int vprintk_emit(int facility, int level,
* it can be printed at the next appropriate moment:
*/
if (!oops_in_progress && !lockdep_recursing(current)) {
- recursion_bug = 1;
+ recursion_bug_cpu = this_cpu;
local_irq_restore(flags);
return 0;
}
@@ -1710,15 +1710,18 @@ asmlinkage int vprintk_emit(int facility, int level,
raw_spin_lock(&logbuf_lock);
logbuf_cpu = this_cpu;
- if (unlikely(recursion_bug)) {
- static const char recursion_msg[] =
- "BUG: recent printk recursion!";
+ if (unlikely(recursion_bug_cpu != -1)) {
+ static char recursion_msg[41];
+ size_t len;
+
+ len = sprintf(recursion_msg,
+ "BUG: recent printk recursion on CPU%d!",
+ recursion_bug_cpu);
- recursion_bug = 0;
+ recursion_bug_cpu = -1;
/* emit KERN_CRIT message */
printed_len += log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0,
- NULL, 0, recursion_msg,
- strlen(recursion_msg));
+ NULL, 0, recursion_msg, len);
}
nmi_message_lost = get_nmi_message_lost();
--
2.7.0.rc0.20.g4b9ab0e
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