6.11-stable review patch. If anyone has any objections, please let me know.
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From: Benjamin Coddington bcodding@redhat.com
[ Upstream commit 3a4ce14d9a6b868e0787e4582420b721c04ee41e ]
Since commit d869da91cccb ("nfs/blocklayout: Fix premature PR key unregistration") an unmount of a pNFS SCSI layout-enabled NFS may dereference a NULL block_device in:
bl_unregister_scsi+0x16/0xe0 [blocklayoutdriver] bl_free_device+0x70/0x80 [blocklayoutdriver] bl_free_deviceid_node+0x12/0x30 [blocklayoutdriver] nfs4_put_deviceid_node+0x60/0xc0 [nfsv4] nfs4_deviceid_purge_client+0x132/0x190 [nfsv4] unset_pnfs_layoutdriver+0x59/0x60 [nfsv4] nfs4_destroy_server+0x36/0x70 [nfsv4] nfs_free_server+0x23/0xe0 [nfs] deactivate_locked_super+0x30/0xb0 cleanup_mnt+0xba/0x150 task_work_run+0x59/0x90 syscall_exit_to_user_mode+0x217/0x220 do_syscall_64+0x8e/0x160
This happens because even though we were able to create the nfs4_deviceid_node, the lookup for the device was unable to attach the block device to the pnfs_block_dev.
If we never found a block device to register, we can avoid this case with the PNFS_BDEV_REGISTERED flag. Move the deref behind the test for the flag.
Fixes: d869da91cccb ("nfs/blocklayout: Fix premature PR key unregistration") Signed-off-by: Benjamin Coddington bcodding@redhat.com Reviewed-by: Christoph Hellwig hch@lst.de Reviewed-by: Chuck Lever chuck.lever@oracle.com Signed-off-by: Trond Myklebust trond.myklebust@hammerspace.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/nfs/blocklayout/dev.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/fs/nfs/blocklayout/dev.c b/fs/nfs/blocklayout/dev.c index 6252f44479457..cab8809f0e0f4 100644 --- a/fs/nfs/blocklayout/dev.c +++ b/fs/nfs/blocklayout/dev.c @@ -20,9 +20,6 @@ static void bl_unregister_scsi(struct pnfs_block_dev *dev) const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops; int status;
- if (!test_and_clear_bit(PNFS_BDEV_REGISTERED, &dev->flags)) - return; - status = ops->pr_register(bdev, dev->pr_key, 0, false); if (status) trace_bl_pr_key_unreg_err(bdev, dev->pr_key, status); @@ -58,7 +55,8 @@ static void bl_unregister_dev(struct pnfs_block_dev *dev) return; }
- if (dev->type == PNFS_BLOCK_VOLUME_SCSI) + if (dev->type == PNFS_BLOCK_VOLUME_SCSI && + test_and_clear_bit(PNFS_BDEV_REGISTERED, &dev->flags)) bl_unregister_scsi(dev); }