diff options
| author | Eric Dumazet | 2011-01-06 10:54:29 -0800 |
|---|---|---|
| committer | David S. Miller | 2011-01-06 10:54:29 -0800 |
| commit | 2c6607c611cb7bf0a6750bcea34a258144e302c5 (patch) | |
| tree | 38156d2a938e5f346d7c4464e132132f7279dcba /net | |
| parent | 3610cda53f247e176bcbb7a7cca64bc53b12acdb (diff) | |
net: add POLLPRI to sock_def_readable()
Leonardo Chiquitto found poll() could block forever on tcp sockets and
Urgent data was received, if the event flag only contains POLLPRI.
He did a bisection and found commit 4938d7e0233 (poll: avoid extra
wakeups in select/poll) was the source of the problem.
Problem is TCP sockets use standard sock_def_readable() function for
their sk_data_ready() handler, and sock_def_readable() doesnt signal
POLLPRI.
Only TCP is affected by the problem. Adding POLLPRI to the list of flags
might trigger unnecessary schedules, but URGENT handling is such a
seldom used feature this seems a good compromise.
Thanks a lot to Leonardo for providing the bisection result and a test
program as well.
Reference : http://www.spinics.net/lists/netdev/msg151793.html
Reported-and-bisected-by: Leonardo Chiquitto <leonardo.lists@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Tested-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/sock.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/sock.c b/net/core/sock.c index a6b9e8061f34..a658aeb6d554 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1908,7 +1908,7 @@ static void sock_def_readable(struct sock *sk, int len) rcu_read_lock(); wq = rcu_dereference(sk->sk_wq); if (wq_has_sleeper(wq)) - wake_up_interruptible_sync_poll(&wq->wait, POLLIN | + wake_up_interruptible_sync_poll(&wq->wait, POLLIN | POLLPRI | POLLRDNORM | POLLRDBAND); sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN); rcu_read_unlock(); |