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Fix a panic during boot caused by inadequate locking of some vt(4) driver

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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
This commit is contained in:
jtl 2017-02-23 01:18:47 +00:00
parent 9b9fd9b451
commit 0f9beefcb0
1 changed files with 5 additions and 3 deletions
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8
sys/kern/subr_terminal.c
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@ -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);
}
/*