git: MPSAFE TTY - Fix deadlock in reporting of probe errors.
commit 438acbcc599b3db8b97949a152027f27f8028066
Author: Matthew Dillon <dillon@apollo.backplane.com>
Date: Sun Aug 29 10:50:47 2010 -0700
MPSAFE TTY - Fix deadlock in reporting of probe errors.
* When sio can't drain it reports the fact, but it was doing it while
still holding com_lock. Rearranging the lock fixes the problem.
* Clean up some unnecessary tty_tokens in critical code paths and rearrange
code to not hold com_lock across tty_token acquisition calls.
* Release the com_lock around breakpoint() (<enter>~^B sequence) to
avoid a deadlock.
* Detect and ignore a reentrant kprintf() to try to avoid a deadlock.
The detection flag is also reset by a panic.
Summary of changes:
sys/dev/serial/sio/sio.c | 57 ++++++++++++++++++++++-----------------------
sys/kern/subr_prf.c | 27 ++++++++++++++++++---
sys/sys/globaldata.h | 7 +++++-
3 files changed, 57 insertions(+), 34 deletions(-)
http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/438acbcc599b3db8b97949a152027f27f8028066
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