svn commit: r332860 - head/sys/kern

[Conrad Meyer]

Next time you encounter something like this, please file a bug.
There's no reason to have broken kernel dumps for a year.  It took 10
minutes to diagnose.

On Tue, Apr 24, 2018 at 10:38 AM, Andrew Gallatin <gallatin at cs.duke.edu> wrote:
> On 04/24/18 13:24, Jonathan T. Looney wrote:
>>
>> On Mon, Apr 23, 2018 at 6:04 PM, John Baldwin <jhb at freebsd.org
>> <mailto:jhb at freebsd.org>> wrote:
>>  >
>>  > I think this is actually a key question.  In my experience to date I
>> have not
>>  > encountered a large number of post-panic assertion failures.  Given
>> that
>>  > we already break all locks and disable assertions for locks I'd be
>> curious
>>  > which assertions are actually failing.  My inclination given my
>> experiences
>>  > to date would be to explicitly ignore those as we do for locking if it
>> is
>>  > constrained set rather than blacklisting all of them.  However, I would
>> be
>>  > most interested in seeing some examples of assertions that are failing.
>>
>> The latest example (the one that prompted me to finally commit this) is in
>> lockmgr_sunlock_try(): 'panic: Assertion (*xp & ~LK_EXCLUSIVE_SPINNERS) ==
>> LK_SHARERS_LOCK(1) failed at /usr/src/sys/kern/kern_lock.c:541'
>>
>> I don't see any obvious recent changes that would have caused this, so
>> this is probably a case where a change to another file suddenly made us trip
>> over this assert.
>
>
> FWIW, that assertion has prevented me from getting a dump from an
> INVARIANTS kernel for at least a year.
>
> Drew