audit: fix endless wait in audit_log_start()

After commit 829199197a43 ("kernel/audit.c: avoid negative sleep
durations") audit emitters will block forever if userspace daemon cannot
handle backlog.

After the timeout the waiting loop turns into busy loop and runs until
daemon dies or returns back to work.  This is a minimal patch for that
bug.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Richard Guy Briggs <rgb@redhat.com>
Cc: Eric Paris <eparis@redhat.com>
Cc: Chuck Anderson <chuck.anderson@oracle.com>
Cc: Dan Duval <dan.duval@oracle.com>
Cc: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/audit.c b/kernel/audit.c
index 91e53d04b6a9e8841e697dcb290f1206468da21a..7b0e23a740ce345987c33f9e012302c24de0f4db 100644 (file)
--- a/kernel/audit.c
+++ b/kernel/audit.c
@@ -1117,9 +1117,10 @@ struct audit_buffer *audit_log_start(struct audit_context *ctx, gfp_t gfp_mask,
 
                        sleep_time = timeout_start + audit_backlog_wait_time -
                                        jiffies;
-                       if ((long)sleep_time > 0)
+                       if ((long)sleep_time > 0) {
                                wait_for_auditd(sleep_time);
-                       continue;
+                               continue;
+                       }
                }
                if (audit_rate_check() && printk_ratelimit())
                        printk(KERN_WARNING