From: Samuel Thibault Date: Thu, 31 Dec 2020 04:28:19 +0000 (+0100) Subject: pppd: Be sure to close /dev/ppp when reconnecting (#184) X-Git-Tag: ppp-2.4.9~33 X-Git-Url: http://git.ozlabs.org/?p=ppp.git;a=commitdiff_plain;h=05bcf644849fd9fb77bf682c996e568ee9ad3a47 pppd: Be sure to close /dev/ppp when reconnecting (#184) From https://bugs.debian.org/306261 When using the kernel PPPoE driver, pppd never closes /dev/ppp when the link has come down. It opens superfluous fds to the device each time it re-opens the connection, with the unclosed ones falsely reported always ready for data by select(). This makes pppd eat up 100% CPU time after the first persist because of the always instantly returning select() on the unclosed fds. The problem also occurs with the upstream version, but does not occur when a pty/tty device is used for the ppp connection. Signed-off-by: Samuel Thibault Co-authored-by: Simon Peter --- diff --git a/pppd/sys-linux.c b/pppd/sys-linux.c index 28bc4be..587242b 100644 --- a/pppd/sys-linux.c +++ b/pppd/sys-linux.c @@ -467,6 +467,13 @@ int generic_establish_ppp (int fd) if (new_style_driver) { int flags; + /* If a ppp_fd is already open, close it first */ + if (ppp_fd >= 0) { + close(ppp_fd); + remove_fd(ppp_fd); + ppp_fd = -1; + } + /* Open an instance of /dev/ppp and connect the channel to it */ if (ioctl(fd, PPPIOCGCHAN, &chindex) == -1) { error("Couldn't get channel number: %m");