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Always explicitly panic in propogate_priority() if we try to propogate

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a lock's priority to a sleeping thread.  When we panic, dump a stack
trace of the thread that is asleep if DDB is compiled into the kernel
just before calling panic().  This is much more informative and useful
for debugging than the current behavior of getting a page fault and not
having an easy way of determining which thread caused the original problem.

MFC after:	1 week
This commit is contained in:
John Baldwin 2006-03-29 23:24:55 +00:00
parent 0e2ce5ce47
commit 4b3b0413d2
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=157275
1 changed files with 14 additions and 8 deletions
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22
sys/kern/subr_turnstile.c
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@ -186,15 +186,21 @@ propagate_priority(struct thread *td)
MPASS(td->td_proc->p_magic == P_MAGIC);
/*
* XXX: The owner of a turnstile can be stale if it is the
* first thread to grab a rlock of a rw lock. In that case
* it is possible for us to be at SSLEEP or some other
* weird state. We should probably just return if the state
* isn't SRUN or SLOCK.
* If the thread is asleep, then we are probably about
* to deadlock. To make debugging this easier, just
* panic and tell the user which thread misbehaved so
* they can hopefully get a stack trace from the truly
* misbehaving thread.
*/
KASSERT(!TD_IS_SLEEPING(td),
("sleeping thread (tid %d) owns a non-sleepable lock",
td->td_tid));
if (TD_IS_SLEEPING(td)) {
printf(
"Sleeping thread (tid %d, pid %d) owns a non-sleepable lock\n",
td->td_tid, td->td_proc->p_pid);
#ifdef DDB
db_trace_thread(td, -1);
#endif
panic("sleeping thread");
}
/*
* If this thread already has higher priority than the