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Code Issues Releases Activity

When entering siocnputc() with (kdb_active), don't acquire (or

Browse Source 
release) the sio spin mutex, as use of synchronization primitives in
the debugger can result in substantial problems.  With this patch in
place entering the debugger via a serial console is made
substantially more reliable.

MFC after:	1 week
Tested by:	kris
Discussed with:	bde
This commit is contained in:
Robert Watson 2005-02-03 10:35:05 +00:00
parent 70ffe5d36d
commit faabfac9ff
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=141186
1 changed files with 9 additions and 5 deletions
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14
sys/dev/sio/sio.c
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@ -2583,16 +2583,20 @@ siocnputc(struct consdev *cd, int c)
}
s = spltty();
need_unlock = 0;
if (sio_inited == 2 && !mtx_owned(&sio_lock)) {
mtx_lock_spin(&sio_lock);
need_unlock = 1;
if (!kdb_active) {
if (sio_inited == 2 && !mtx_owned(&sio_lock)) {
mtx_lock_spin(&sio_lock);
need_unlock = 1;
}
}
siocnopen(&sp, iobase, speed);
siocntxwait(iobase);
outb(iobase + com_data, c);
siocnclose(&sp, iobase);
if (need_unlock)
mtx_unlock_spin(&sio_lock);
if (!kdb_active) {
if (need_unlock)
mtx_unlock_spin(&sio_lock);
}
splx(s);
}