Re: 8.1 tstile lockup after nfs send error 51

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

Here are stack traces of all the frozen processes (with a few newlines 
inserted manually):

Crash version 8.1_STABLE, image version 8.1_STABLE.
Output from a running system is unreliable.

crash> trace/t 0t16306
trace: pid 16306 lid 1 at 0xffff8001578daa20
sleepq_block() at sleepq_block+0x97
turnstile_block() at turnstile_block+0x24f
rw_vector_enter() at rw_vector_enter+0x120
genfs_lock() at genfs_lock+0x47
VOP_LOCK() at VOP_LOCK+0x80
vn_lock() at vn_lock+0x11
nfs_root() at nfs_root+0x2b
VFS_ROOT() at VFS_ROOT+0x35
lookup_once() at lookup_once+0x250
namei_tryemulroot.constprop.9() at namei_tryemulroot.constprop.9+0x3b1
namei() at namei+0x43
fd_nameiat.isra.2() at fd_nameiat.isra.2+0x54
do_sys_statat() at do_sys_statat+0x77
sys___stat50() at sys___stat50+0x28
syscall() at syscall+0x1ec
--- syscall (number 439) ---
787fc74f98ca:

crash> trace/t 0t16685
trace: pid 16685 lid 1 at 0xffff80015791aae0
sleepq_block() at sleepq_block+0x97
turnstile_block() at turnstile_block+0x24f
rw_vector_enter() at rw_vector_enter+0x120
genfs_lock() at genfs_lock+0x47
VOP_LOCK() at VOP_LOCK+0x80
vn_lock() at vn_lock+0x11
nfs_root() at nfs_root+0x2b
VFS_ROOT() at VFS_ROOT+0x35
lookup_once() at lookup_once+0x250
namei_tryemulroot.constprop.9() at namei_tryemulroot.constprop.9+0x3b1
namei() at namei+0x43
chdir_lookup() at chdir_lookup+0x70
sys_chdir() at sys_chdir+0x26
syscall() at syscall+0x1ec
--- syscall (number 12) ---
758c3b8820ca:

crash> trace/t 0t19979
trace: pid 19979 lid 1 at 0xffff80013ed7ea20
sleepq_block() at sleepq_block+0x97
turnstile_block() at turnstile_block+0x24f
rw_vector_enter() at rw_vector_enter+0x120
genfs_lock() at genfs_lock+0x47
VOP_LOCK() at VOP_LOCK+0x80
vn_lock() at vn_lock+0x11
nfs_root() at nfs_root+0x2b
VFS_ROOT() at VFS_ROOT+0x35
lookup_once() at lookup_once+0x250
namei_tryemulroot.constprop.9() at namei_tryemulroot.constprop.9+0x3b1
namei() at namei+0x43
fd_nameiat.isra.2() at fd_nameiat.isra.2+0x54
do_sys_statat() at do_sys_statat+0x77
sys___lstat50() at sys___lstat50+0x25
syscall() at syscall+0x1ec
--- syscall (number 441) ---
7c0a9c4a1a7a:

crash> trace/t 0t25025
trace: pid 25025 lid 1 at 0xffff8001576628a0
sleepq_block() at sleepq_block+0x97
turnstile_block() at turnstile_block+0x24f
rw_vector_enter() at rw_vector_enter+0x120
genfs_lock() at genfs_lock+0x47
VOP_LOCK() at VOP_LOCK+0x80
vn_lock() at vn_lock+0x11
nfs_lookup() at nfs_lookup+0xf84
VOP_LOOKUP() at VOP_LOOKUP+0x85
lookup_once() at lookup_once+0x18d
namei_tryemulroot.constprop.9() at namei_tryemulroot.constprop.9+0x3b1
namei() at namei+0x43
fd_nameiat.isra.2() at fd_nameiat.isra.2+0x54
do_sys_statat() at do_sys_statat+0x77
sys___stat50() at sys___stat50+0x28
syscall() at syscall+0x1ec
--- syscall (number 439) ---
6fd53d4f98ca:

crash> trace/t 0t28321
trace: pid 28321 lid 1 at 0xffff80013f8768a0
sleepq_block() at sleepq_block+0x97
turnstile_block() at turnstile_block+0x24f
rw_vector_enter() at rw_vector_enter+0x120
genfs_lock() at genfs_lock+0x47
VOP_LOCK() at VOP_LOCK+0x80
vn_lock() at vn_lock+0x11
nfs_lookup() at nfs_lookup+0xf84
VOP_LOOKUP() at VOP_LOOKUP+0x85
lookup_once() at lookup_once+0x18d
namei_tryemulroot.constprop.9() at namei_tryemulroot.constprop.9+0x3b1
namei() at namei+0x43
fd_nameiat.isra.2() at fd_nameiat.isra.2+0x54
do_sys_statat() at do_sys_statat+0x77
sys___stat50() at sys___stat50+0x28
syscall() at syscall+0x1ec
--- syscall (number 439) ---
7656ab6f98ca:

crash> trace/t 0t18618
trace: pid 18618 lid 1 at 0xffff80013f9b2a20
sleepq_block() at sleepq_block+0x97
turnstile_block() at turnstile_block+0x24f
rw_vector_enter() at rw_vector_enter+0x120
genfs_lock() at genfs_lock+0x47
VOP_LOCK() at VOP_LOCK+0x80
vn_lock() at vn_lock+0x11
nfs_root() at nfs_root+0x2b
VFS_ROOT() at VFS_ROOT+0x35
lookup_once() at lookup_once+0x250
namei_tryemulroot.constprop.9() at namei_tryemulroot.constprop.9+0x3b1
namei() at namei+0x43
fd_nameiat.isra.2() at fd_nameiat.isra.2+0x54
do_sys_statat() at do_sys_statat+0x77
sys___lstat50() at sys___lstat50+0x25
syscall() at syscall+0x1ec
--- syscall (number 441) ---
7cbc7f0a1a7a:

crash> trace/t 0t22881
trace: pid 22881 lid 1 at 0xffff80013eef6a20
sleepq_block() at sleepq_block+0x97
turnstile_block() at turnstile_block+0x24f
rw_vector_enter() at rw_vector_enter+0x120
genfs_lock() at genfs_lock+0x47
VOP_LOCK() at VOP_LOCK+0x80
vn_lock() at vn_lock+0x11
nfs_root() at nfs_root+0x2b
VFS_ROOT() at VFS_ROOT+0x35
lookup_once() at lookup_once+0x250
namei_tryemulroot.constprop.9() at namei_tryemulroot.constprop.9+0x3b1
namei() at namei+0x43
fd_nameiat.isra.2() at fd_nameiat.isra.2+0x54
do_sys_statat() at do_sys_statat+0x77
sys___stat50() at sys___stat50+0x28
syscall() at syscall+0x1ec
--- syscall (number 439) ---
792b4e4f98ca: