> In the log, at the very early stage line 894, aufs produces BUG msg.
:::
> It happened when mkdir[847] issues exit(2). At exitting, all opened
> file descriptors are closed by kernel and aufs_release_dir() is called.
> By enabling CONFIG_AUFS_DEBUG, aufs checks the state of the internal
> lock and found it is still locked which sould not happen. I don't think
> it sane. I am really doubtful "Is it really correctly built?"
Reading the source files of debian kernel 4.19.67-2+deb10u1, I've found
a suspicious thing.
- aufs4-mmap.patch is applied in-correctly,
or in-correct version is applied,
or bad aufs version which contained a in-correct version is used.
The last part of mm/nommu.c:do_mmap(),
fput(vma->vm_file);
should be
vma_fput(vma);
This fput() and vma_fput() affect the reference counter (lifetime) of
'file' object in kernel. Once it gets crazy, aufs internal function
au_finfo_fin() will produce the BUG line, just as your syslog.
So I'd say, this mm/nommu.c in debian kernel has a bug, and it must be
the first thing to solve your problem.
J. R. Okajima
