On Sun, Oct 30, 2016 at 6:20 AM, Eric Dumazet [off-list ref] wrote:

On Sun, 2016-10-30 at 05:41 +0100, Andrey Konovalov wrote:

quoted

Sorry, the warning is still there.

I'm not sure adding sched_annotate_sleep() does anything, since it's
defined as (in case CONFIG_DEBUG_ATOMIC_SLEEP is not set):
# define sched_annotate_sleep() do { } while (0)

Thanks again for testing.

But you do have CONFIG_DEBUG_ATOMIC_SLEEP set, which triggers a check in
__might_sleep() :

WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change,

Relevant commit is 00845eb968ead28007338b2bb852b8beef816583
("sched: don't cause task state changes in nested sleep debugging")

Another relevant commit was 26cabd31259ba43f68026ce3f62b78094124333f
("sched, net: Clean up sk_wait_event() vs. might_sleep()")

Before release_sock() could process the backlog in process context, only
lock_sock() could trigger the issue, so my fix at that time was commit
cb7cf8a33ff73cf638481d1edf883d8968f934f8 ("inet: Clean up
inet_csk_wait_for_connect() vs. might_sleep()")

Thanks for the context, but isn't the original warning reported by Andrey is
from inet_wait_for_connect()? You seem only patch some dccp function
which is why it is still there?

It should be the following, no?

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 9648c97..bbd8159 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c

@@ -544,6 +544,7 @@ static long inet_wait_for_connect(struct sock *sk,

long timeo, int writebias)
         * without closing the socket.
         */
        while ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
+               sched_annotate_sleep();
                release_sock(sk);
                timeo = schedule_timeout(timeo);
                lock_sock(sk);