diff options
| -rw-r--r-- | lib/netlink-socket.c | 10 | ||||
| -rw-r--r-- | lib/netlink-socket.h | 2 |
2 files changed, 12 insertions, 0 deletions
diff --git a/lib/netlink-socket.c b/lib/netlink-socket.c index 42ba7e1fc..8fd393340 100644 --- a/lib/netlink-socket.c +++ b/lib/netlink-socket.c @@ -714,6 +714,7 @@ nl_dump_start(struct nl_dump *dump, int protocol, const struct ofpbuf *request) atomic_init(&dump->status, status << 1); dump->nl_seq = nl_msg_nlmsghdr(request)->nlmsg_seq; dump->status_seq = seq_create(); + ovs_mutex_init(&dump->mutex); } /* Attempts to retrieve another reply from 'dump' into 'buffer'. 'dump' must @@ -756,7 +757,15 @@ nl_dump_next(struct nl_dump *dump, struct ofpbuf *reply, struct ofpbuf *buffer) return false; } + /* Take the mutex here to avoid an in-kernel race. If two threads try + * to read from a Netlink dump socket at once, then the socket error + * can be set to EINVAL, which will be encountered on the next recv on + * that socket, which could be anywhere due to the way that we pool + * Netlink sockets. Serializing the recv calls avoids the issue. */ + ovs_mutex_lock(&dump->mutex); retval = nl_sock_recv__(dump->sock, buffer, false); + ovs_mutex_unlock(&dump->mutex); + if (retval) { ofpbuf_clear(buffer); if (retval == EAGAIN) { @@ -835,6 +844,7 @@ nl_dump_done(struct nl_dump *dump) } nl_pool_release(dump->sock); seq_destroy(dump->status_seq); + ovs_mutex_destroy(&dump->mutex); return status >> 1; } diff --git a/lib/netlink-socket.h b/lib/netlink-socket.h index dd3240907..8ac201aac 100644 --- a/lib/netlink-socket.h +++ b/lib/netlink-socket.h @@ -52,6 +52,7 @@ #include <stdint.h> #include "ofpbuf.h" #include "ovs-atomic.h" +#include "ovs-thread.h" struct nl_sock; @@ -114,6 +115,7 @@ struct nl_dump { atomic_uint status; /* Low bit set if we read final message. * Other bits hold an errno (0 for success). */ struct seq *status_seq; /* Tracks changes to the above 'status'. */ + struct ovs_mutex mutex; }; void nl_dump_start(struct nl_dump *, int protocol, |