kernel/drivers/net/ppp/ppp_async.c, branch linux-4.1.y

tty: Fix recursive deadlock in tty_perform_flush()

2013-03-18T23:52:24Z

tty_perform_flush() can deadlock when called while holding a line discipline reference. By definition, all ldisc drivers hold a ldisc reference, so calls originating from ldisc drivers must not block for a ldisc reference. The deadlock can occur when: CPU 0 | CPU 1 | tty_ldisc_ref(tty) | .... | tty_ldisc_ref_wait(tty) | | CPU 0 cannot progess because it cannot obtain an ldisc reference with the line discipline has been halted (thus no new references are granted). CPU 1 cannot progress because an outstanding ldisc reference has not been released. An in-tree call-tree audit of tty_perform_flush() [1] shows 5 ldisc drivers calling tty_perform_flush() indirectly via n_tty_ioctl_helper() and 2 ldisc drivers calling directly. A single tty driver safely uses the function. [1] Recursive usage: /* These functions are line discipline ioctls and thus * recursive wrt line discipline references */ tty_perform_flush() - ./drivers/tty/tty_ioctl.c n_tty_ioctl_helper() hci_uart_tty_ioctl(default) - drivers/bluetooth/hci_ldisc.c (N_HCI) n_hdlc_tty_ioctl(default) - drivers/tty/n_hdlc.c (N_HDLC) gsmld_ioctl(default) - drivers/tty/n_gsm.c (N_GSM0710) n_tty_ioctl(default) - drivers/tty/n_tty.c (N_TTY) gigaset_tty_ioctl(default) - drivers/isdn/gigaset/ser-gigaset.c (N_GIGASET_M101) ppp_synctty_ioctl(TCFLSH) - drivers/net/ppp/pps_synctty.c ppp_asynctty_ioctl(TCFLSH) - drivers/net/ppp/ppp_async.c Non-recursive use: tty_perform_flush() - drivers/tty/tty_ioctl.c ipw_ioctl(TCFLSH) - drivers/tty/ipwireless/tty.c /* This function is a tty i/o ioctl method, which * is invoked by tty_ioctl() */ Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman

ppp: avoid false drop_monitor false positives

2012-05-19T06:32:30Z

Call consume_skb() in place of kfree_skb() were appropriate. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller

ppp: Replace uses of with

2012-03-05T01:41:38Z

Since all that include/linux/if_ppp.h does is #include , this replaces the occurrences of #include with #include . It also corrects an error in Documentation/networking/l2tp.txt, where it referenced include/linux/if_ppp.h as the source of some definitions that are actually now defined in include/linux/if_pppol2tp.h. Signed-off-by: Paul Mackerras Signed-off-by: David S. Miller

ppp: Move the PPP drivers

2011-08-27T07:58:26Z

Move the PPP drivers into drivers/net/ppp/ and make the necessary Kconfig and Makefile changes. CC: Paul Mackerras CC: Frank Cusack CC: Michal Ostrowski CC: Michal Ostrowski CC: Dmitry Kozlov Signed-off-by: Jeff Kirsher