Ceph » Linux kernel client

on current master, i was doing umount on a sluggish cluster, and

[ 1748.480000] BUG: failure at mm/mempool.c:186/mempool_destroy()!
[ 1748.480000] Kernel panic - not syncing: BUG!
[ 1748.480000] Call Trace: 
[ 1748.480000] 9e62bc38:  [<6053edf0>] panic+0xea/0x1dc
[ 1748.480000] 9e62bc58:  [<6053ef82>] printk+0xa0/0xa2
[ 1748.480000] 9e62bcd8:  [<60028fb3>] set_signals+0x1c/0x2e
[ 1748.480000] 9e62bcf8:  [<60089e8c>] kfree+0xf4/0xfd
[ 1748.480000] 9e62bd38:  [<600664c2>] mempool_destroy+0x33/0x3a
[ 1748.480000] 9e62bd48:  [<6052ef06>] ceph_msgpool_destroy+0xd/0xf
[ 1748.480000] 9e62bd58:  [<605315a1>] ceph_osdc_stop+0x90/0xa0
[ 1748.480000] 9e62bd78:  [<6052961b>] ceph_destroy_client+0x63/0xf1
[ 1748.480000] 9e62bd98:  [<60404bee>] destroy_fs_client+0x95/0xe3
[ 1748.480000] 9e62bdb8:  [<60404cb1>] ceph_kill_sb+0x75/0x7e
[ 1748.480000] 9e62bdd8:  [<6008f003>] deactivate_locked_super+0x20/0x45
[ 1748.480000] 9e62bdf8:  [<6008f87b>] deactivate_super+0x3f/0x44
[ 1748.480000] 9e62be18:  [<600a57e9>] mntput_no_expire+0x9a/0x9f
[ 1748.480000] 9e62be38:  [<600a636c>] sys_umount+0x2ee/0x319
[ 1748.480000] 9e62bee8:  [<6001c44c>] handle_syscall+0x58/0x70
[ 1748.480000] 9e62bf08:  [<6002bd1b>] userspace+0x2dd/0x38a
[ 1748.480000] 9e62bfc8:  [<60019a6d>] fork_handler+0x7d/0x84