[PATCH] time/timekeeping_debug: use printk_deferred()

[Sergey Senozhatsky]

Do not call printk() from tk_debug_account_sleep_time(), because
tk_debug_account_sleep_time() is called under tk_core seq lock.
It's not safe to call printk() under tk_core, because console_sem
invokes scheduled (via wake_up_process()->activate_task()), which,
in turn, can call timekeeping code again, for instance, via
get_time()->ktime_get(). This may result in infinite loop on
tk_core.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
---
 kernel/time/timekeeping_debug.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/time/timekeeping_debug.c b/kernel/time/timekeeping_debug.c
index ca9fb800336b..b8f7146c3538 100644
--- a/kernel/time/timekeeping_debug.c
+++ b/kernel/time/timekeeping_debug.c
@@ -75,7 +75,8 @@ void tk_debug_account_sleep_time(struct timespec64 *t)
 	int bin = min(fls(t->tv_sec), NUM_BINS-1);
 
 	sleep_time_bin[bin]++;
-	pr_info("Suspended for %lld.%03lu seconds\n", (s64)t->tv_sec,
+	printk_deferred(KERN_INFO "Suspended for %lld.%03lu seconds\n",
+			(s64)t->tv_sec,
 			t->tv_nsec / NSEC_PER_MSEC);
 }
 
-- 
2.11.1