Just got this from a LOCKDEBUG kernel under high pressure:

pool_get(PR_WAITOK) with held simple_lock 0xc03dbcb8 CPU 0 /sys/kern/vfs_subr.c:462
pool_get(c041e8e0,2,3da,c02a355c,c105b780) at pool_get+0x57
uvm_map_clip_start(c03f0a40,c105b780,e4ae1000,c02a4755,c03f0b20) at uvm_map_clip_start+0xe2
uvm_unmap_remove(c03f0a40,e4ae1000,e4ae2000,e41dca0c,0) at uvm_unmap_remove+0x5d
uvm_unmap(c03f0a40,e4ae1000,e4ae2000,601727,0) at uvm_unmap+0x10e
uvm_km_kmemalloc(c03f0a40,c03f0940,1000,600000,0) at uvm_km_kmemalloc+0x141
uvm_km_alloc_poolpage1(c03f0a40,c03f0940,0,c023025b,c1162e18) at uvm_km_alloc_poolpage1+0x3b
pool_page_alloc_nointr(c041cd80,0,0,c01edaa6,0) at pool_page_alloc_nointr+0x23
pool_allocator_alloc(c041cd80,0,e41dcb30,c02418a2,c041cdec) at pool_allocator_alloc+0x1f
pool_get(c041cd80,0,1ce,c0209e5e,e41dcbbc) at pool_get+0x1eb
getnewvnode(1,c1162e00,c0f77200,e41dcbbc,8000) at getnewvnode+0xbb
ffs_vget(c1162e00,551de,e41dcc74,ffffffff,e49de99c) at ffs_vget+0x4f
ffs_valloc(e41dcc2c,e49de99c,200,c0269fae,8180) at ffs_valloc+0xef
VOP_VALLOC(e49de99c,8180,c11aa280,e41dcc74,e41dcddc) at VOP_VALLOC+0x3b
ufs_makeinode(8180,e49de99c,e41dcef0,e41dcf04,e49de99c) at ufs_makeinode+0x5c
ufs_create(e41dcddc,3e109ea7,e41dce00,c026a18b,e41dce3c) at ufs_create+0x2c
VOP_CREATE(e49de99c,e41dcef0,e41dcf04,e41dce3c,e49de99c) at VOP_CREATE+0x3b
vn_open(e41dcee0,203,180,e41d9000,e41dcf80) at vn_open+0xad
sys_open(e4137df0,e41dcf80,e41dcf78,e4137df0,0) at sys_open+0xc5
syscall_plain(1f,1f,bfbf001f,1f,bfbfb762) at syscall_plain+0xa7

-- 
Juergen Hannken-Illjes - hannken@eis.cs.tu-bs.de - TU Braunschweig (Germany)