dst: call cond_resched() in dst_gc_task()

Kernel bugzilla #15239

On some workloads, it is quite possible to get a huge dst list to
process in dst_gc_task(), and trigger soft lockup detection.

Fix is to call cond_resched(), as we run in process context.

Reported-by: Pawel Staszewski <pstaszewski@itcare.pl>
Tested-by: Pawel Staszewski <pstaszewski@itcare.pl>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dst.c b/net/core/dst.c
index 57bc4d5b8d084c053cded6ebddfe66bf6255d9f5..cb1b3488b739837fcff71c10d36694f2ea3ab393 100644 (file)
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -17,6 +17,7 @@
 #include <linux/string.h>
 #include <linux/types.h>
 #include <net/net_namespace.h>
+#include <linux/sched.h>
 
 #include <net/dst.h>
 
@@ -79,6 +80,7 @@ loop:
        while ((dst = next) != NULL) {
                next = dst->next;
                prefetch(&next->next);
+               cond_resched();
                if (likely(atomic_read(&dst->__refcnt))) {
                        last->next = dst;
                        last = dst;