From 0f9beefcb0a50b15c03a0c62dc0f82cbaa001850 Mon Sep 17 00:00:00 2001 From: jtl Date: Thu, 23 Feb 2017 01:18:47 +0000 Subject: [PATCH] Fix a panic during boot caused by inadequate locking of some vt(4) driver data structures. vt_change_font() calls vtbuf_grow() to change some vt driver data structures. It uses TF_MUTE to prevent the console from trying to use those data structures while it changes them. During the early stage of the boot process, the vt driver's tc_done routine uses those data structures; however, it is currently called outside the TF_MUTE check. Move the tc_done routine inside the locked TF_MUTE check. PR: 217282 Reviewed by: ed, ray Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D9709 --- sys/kern/subr_terminal.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/sys/kern/subr_terminal.c b/sys/kern/subr_terminal.c index 76c6cfbf6453..5ac6a03b8979 100644 --- a/sys/kern/subr_terminal.c +++ b/sys/kern/subr_terminal.c @@ -375,7 +375,10 @@ termtty_outwakeup(struct tty *tp) TERMINAL_UNLOCK_TTY(tm); } - tm->tm_class->tc_done(tm); + TERMINAL_LOCK_TTY(tm); + if (!(tm->tm_flags & TF_MUTE)) + tm->tm_class->tc_done(tm); + TERMINAL_UNLOCK_TTY(tm); if (flags & TF_BELL) tm->tm_class->tc_bell(tm); } @@ -545,10 +548,9 @@ termcn_cnputc(struct consdev *cp, int c) teken_set_curattr(&tm->tm_emulator, &kernel_message); teken_input(&tm->tm_emulator, &cv, 1); teken_set_curattr(&tm->tm_emulator, &backup); + tm->tm_class->tc_done(tm); } TERMINAL_UNLOCK_CONS(tm); - - tm->tm_class->tc_done(tm); } /*