RE: [PATCH v2 vfio 1/3] pds/vfio: Fix spinlock bad magic BUG

[Shameerali Kolothum Thodi]

> -----Original Message-----
> From: Brett Creeley [mailto:brett.creeley@xxxxxxx]
> Sent: 12 October 2023 00:01
> To: jgg@xxxxxxxx; yishaih@xxxxxxxxxx; Shameerali Kolothum Thodi
> <shameerali.kolothum.thodi@xxxxxxxxxx>; kevin.tian@xxxxxxxxx;
> alex.williamson@xxxxxxxxxx; dan.carpenter@xxxxxxxxxx
> Cc: kvm@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> brett.creeley@xxxxxxx; shannon.nelson@xxxxxxx
> Subject: [PATCH v2 vfio 1/3] pds/vfio: Fix spinlock bad magic BUG
> 
> The following BUG was found when running on a kernel with
> CONFIG_DEBUG_SPINLOCK=y set:
> 
> BUG: spinlock bad magic on CPU#2, bash/2481
>  lock: 0xffff8d6052a88f50, .magic: 00000000, .owner:
> <none>/-1, .owner_cpu: 0
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x36/0x50
>  do_raw_spin_lock+0x79/0xc0
>  pds_vfio_reset+0x1d/0x60 [pds_vfio_pci]
>  pci_reset_function+0x4b/0x70
>  reset_store+0x5b/0xa0
>  kernfs_fop_write_iter+0x137/0x1d0
>  vfs_write+0x2de/0x410
>  ksys_write+0x5d/0xd0
>  do_syscall_64+0x3b/0x90
>  entry_SYSCALL_64_after_hwframe+0x6e/0xd8
> 
> As shown, the .magic: 00000000, does not match the expected value. This
> is because spin_lock_init() is never called for the reset_lock. Fix
> this by calling spin_lock_init(&pds_vfio->reset_lock) when initializing
> the device.
> 
> Signed-off-by: Brett Creeley <brett.creeley@xxxxxxx>
> Reviewed-by: Shannon Nelson <shannon.nelson@xxxxxxx>

Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>

I think this needs to be fixed in HiSilicon driver as well. I will send out a 
patch.

Thanks,
Shameer

> ---
>  drivers/vfio/pci/pds/vfio_dev.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/vfio/pci/pds/vfio_dev.c b/drivers/vfio/pci/pds/vfio_dev.c
> index 649b18ee394b..c351f588fa13 100644
> --- a/drivers/vfio/pci/pds/vfio_dev.c
> +++ b/drivers/vfio/pci/pds/vfio_dev.c
> @@ -155,6 +155,8 @@ static int pds_vfio_init_device(struct vfio_device
> *vdev)
> 
>  	pds_vfio->vf_id = vf_id;
> 
> +	spin_lock_init(&pds_vfio->reset_lock);
> +
>  	vdev->migration_flags = VFIO_MIGRATION_STOP_COPY |
> VFIO_MIGRATION_P2P;
>  	vdev->mig_ops = &pds_vfio_lm_ops;
>  	vdev->log_ops = &pds_vfio_log_ops;
> --
> 2.17.1