mdev: re-initialize if uevent messages were lost

If the netlink read() failed with ENOBUFS we know that we have missed at
least one message due to a socket receive buffer overrun. The only way
how to recover is to drop the old socket, open a fresh one and make a
cold-plug scan of the current system state.

Signed-off-by: Jan Klötzke <jan@kloetzke.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/util-linux/mdev.c b/util-linux/mdev.c
index 4c00a2d7e..d4f06c128 100644
--- a/util-linux/mdev.c
+++ b/util-linux/mdev.c
@@ -1199,6 +1199,16 @@ static void daemon_loop(char *temp, int fd)
 
                 len = safe_read(fd, netbuf, sizeof(netbuf) - 1);
                 if (len < 0) {
+                        if (errno == ENOBUFS) {
+                                /*
+                                 * We ran out of socket receive buffer space.
+                                 * Start from scratch.
+                                 */
+                                dbg1s("uevent overrun, rescanning");
+                                close(fd);
+                                fd = daemon_init(temp);
+                                continue;
+                        }
                         bb_simple_perror_msg_and_die("read");
                 }
                 end = netbuf + len;