diff options
| author | Brett Creeley <brett.creeley@amd.com> | 2023-11-22 20:25:31 +0100 |
|---|---|---|
| committer | Alex Williamson <alex.williamson@redhat.com> | 2023-11-27 17:29:03 +0100 |
| commit | 91aeb563bd4332e2988f8c0f64f125c4ecb5bcb3 (patch) | |
| tree | 4053dca1fd00dae047310809ce17ae5d4883d2ba /drivers/vfio | |
| parent | Linux 6.7-rc3 (diff) | |
| download | linux-91aeb563bd4332e2988f8c0f64f125c4ecb5bcb3.tar.xz linux-91aeb563bd4332e2988f8c0f64f125c4ecb5bcb3.zip | |
vfio/pds: Fix mutex lock->magic != lock warning
The following BUG was found when running on a kernel with
CONFIG_DEBUG_MUTEXES=y set:
DEBUG_LOCKS_WARN_ON(lock->magic != lock)
RIP: 0010:mutex_trylock+0x10d/0x120
Call Trace:
<TASK>
? __warn+0x85/0x140
? mutex_trylock+0x10d/0x120
? report_bug+0xfc/0x1e0
? handle_bug+0x3f/0x70
? exc_invalid_op+0x17/0x70
? asm_exc_invalid_op+0x1a/0x20
? mutex_trylock+0x10d/0x120
? mutex_trylock+0x10d/0x120
pds_vfio_reset+0x3a/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, lock->magic != lock. This is because
mutex_init(&pds_vfio->state_mutex) is called in the VFIO open path. So,
if a reset is initiated before the VFIO device is opened the mutex will
have never been initialized. Fix this by calling
mutex_init(&pds_vfio->state_mutex) in the VFIO init path.
Also, don't destroy the mutex on close because the device may
be re-opened, which would cause mutex to be uninitialized. Fix this by
implementing a driver specific vfio_device_ops.release callback that
destroys the mutex before calling vfio_pci_core_release_dev().
Fixes: bb500dbe2ac6 ("vfio/pds: Add VFIO live migration support")
Signed-off-by: Brett Creeley <brett.creeley@amd.com>
Reviewed-by: Shannon Nelson <shannon.nelson@amd.com>
Link: https://lore.kernel.org/r/20231122192532.25791-2-brett.creeley@amd.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
| -rw-r--r-- | drivers/vfio/pci/pds/vfio_dev.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/drivers/vfio/pci/pds/vfio_dev.c b/drivers/vfio/pci/pds/vfio_dev.c index 649b18ee394b..8c9fb87b13e1 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; + mutex_init(&pds_vfio->state_mutex); + vdev->migration_flags = VFIO_MIGRATION_STOP_COPY | VFIO_MIGRATION_P2P; vdev->mig_ops = &pds_vfio_lm_ops; vdev->log_ops = &pds_vfio_log_ops; @@ -168,6 +170,16 @@ static int pds_vfio_init_device(struct vfio_device *vdev) return 0; } +static void pds_vfio_release_device(struct vfio_device *vdev) +{ + struct pds_vfio_pci_device *pds_vfio = + container_of(vdev, struct pds_vfio_pci_device, + vfio_coredev.vdev); + + mutex_destroy(&pds_vfio->state_mutex); + vfio_pci_core_release_dev(vdev); +} + static int pds_vfio_open_device(struct vfio_device *vdev) { struct pds_vfio_pci_device *pds_vfio = @@ -179,7 +191,6 @@ static int pds_vfio_open_device(struct vfio_device *vdev) if (err) return err; - mutex_init(&pds_vfio->state_mutex); pds_vfio->state = VFIO_DEVICE_STATE_RUNNING; pds_vfio->deferred_reset_state = VFIO_DEVICE_STATE_RUNNING; @@ -199,14 +210,13 @@ static void pds_vfio_close_device(struct vfio_device *vdev) pds_vfio_put_save_file(pds_vfio); pds_vfio_dirty_disable(pds_vfio, true); mutex_unlock(&pds_vfio->state_mutex); - mutex_destroy(&pds_vfio->state_mutex); vfio_pci_core_close_device(vdev); } static const struct vfio_device_ops pds_vfio_ops = { .name = "pds-vfio", .init = pds_vfio_init_device, - .release = vfio_pci_core_release_dev, + .release = pds_vfio_release_device, .open_device = pds_vfio_open_device, .close_device = pds_vfio_close_device, .ioctl = vfio_pci_core_ioctl, |