Re: [BUG] btrfs: Assertion failed in btrfs_exclop_balance on balance ioctl

David Sterba
2025-06-26T14:12:00Z

On Thu, Jun 26, 2025 at 06:50:17PM +0930, Qu Wenruo wrote:
>
>
> 在 2025/6/26 17:37, cen zhang 写道:
> > Hello Btrfs maintainers,
> >
> > I would like to report a kernel BUG, which appears to be a state
> > management issue in the balance ioctl path.
> >
> > The kernel panics due to a failed assertion in btrfs_exclop_balance()
> > at fs/btrfs/fs.c:127. The assertion fs_info->exclusive_operation ==
> > BTRFS_EXCLOP_BALANCE_PAUSED fails, indicating that the function was
> > called with an unexpected exclusive operation state.
> >
> > Here are the relevant details:
> >
> > Kernel Version: 6.16.0-rc1-g7f6432600434-dirty
> > Hardware: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996)
>
> Reproducer please?
>
> I guess you guys are running syzbot, then please provide the usual
> syzbot assets.

This might be the but that was once reported, I'll try to look it up,
some edge case of the exclusive ops and the convoluted balance states.