Re: git: b1de02c415de - main - vfs offset: fix assertion failure in face of racing ffofset and setfl locking

I'll take care of it on Wednesday

On Sun, Oct 5, 2025 at 11:56 PM Konstantin Belousov <kostikbel@gmail.com> wrote:
>
> On Sun, Oct 05, 2025 at 09:22:01PM +0000, Mateusz Guzik wrote:
> > The branch main has been updated by mjg:
> >
> > URL: https://cgit.FreeBSD.org/src/commit/?id=b1de02c415de5df2d24d8021827634fc095b7a26
> >
> > commit b1de02c415de5df2d24d8021827634fc095b7a26
> > Author:     Mateusz Guzik <mjg@FreeBSD.org>
> > AuthorDate: 2025-10-05 17:03:54 +0000
> > Commit:     Mateusz Guzik <mjg@FreeBSD.org>
> > CommitDate: 2025-10-05 21:21:34 +0000
> >
> >     vfs offset: fix assertion failure in face of racing ffofset and setfl locking
> >
> >     Both use the same 16 bit var to store their locked and waiters bits,
> >     then this in file_v_unlock:
> >
> >             state = atomic_load_16(flagsp);
> >             if ((state & lock_wait_bit) == 0 &&
> >                 atomic_cmpset_rel_16(flagsp, state, state & ~lock_bit))
> >                     return;
> >
> >     can fail if for example foffset is being unlocked while setfl is getting
> >     locked.
> >
> >     Afterwards the code assumes there are blocked waiters on foffset.
> >
> >     Reviewed by: kib, markj
> >     Sponsored by:   Rubicon Communications, LLC ("Netgate")
> >     Differential Revision: https://reviews.freebsd.org/D52915
>
> This should be merged both to stable/15 and 14.