panic: VERIFY(ZFS_TEARDOWN_READ_HELD(zfsvfs)) failed

[Andriy Gapon]

On 06/11/2020 22:58, Mateusz Guzik wrote:
> Note the underlying primitive was recently replaced.
> 
> One immediate thing to check would be exact state of the lock.
> READ_HELD checks for reading only, fails if you have this
> write-locked, which is a plausible explanation if you are coming in
> from less likely codepath.
> 
> iow what's the backtrace and can you print both rms->readers and
> rms->owner (+ curthread)

Unfortunately, I do not have a vmcore, only a picture of the screen.

ZFS code looks correct, the lock should be held in read mode, so indeed I
suspect that the problem is with rms.

It looks like rms_rlock() does not change rmslock::readers, but rms_rowned()
checks it?

That's just from a first, super-quick look at the code.


> On 11/6/20, Andriy Gapon <avg at freebsd.org> wrote:
>>
>> The subject panic happens for me with r367410 when mounting root
>> filesystem.
>> The panic is in zfs_freebsd_cached_lookup -> zfs_lookup -> zfs_dirlook.
>> I have a picture of the screen with a little bit more details, I'll share it
>> later.

-- 
Andriy Gapon