linker_load_module(NULL, "modname", ...) from thread with no user process

[Gleb Smirnoff]

  Dear hackers,

  there is problem when linker_load_module() is called from a kernel thread with
no associated user process, and it asks to load module by name, not by filename.
With such parameters it requires looking through device.hints file.
And vn_open() assumes that ndp->ni_cnd->cn_thread->td_proc is valid.

Any ideas how to solve this?

Here is a sample backtrace:

#8  0xc06ba0b3 in trap (frame=
      {tf_fs = -1946419176, tf_es = 2106261520, tf_ds = 607387664, tf_edi = -877233464, tf_esi = -1066365186, tf_ebp = -877234268, tf_isp = -877234312, tf_ebx = 2065, tf_edx = -877233504, tf_ecx = 0, tf_eax = -1051754144, tf_trapno = 12, tf_err = 0, tf_eip = -1068097648, tf_cs = 8, tf_eflags = 66182, tf_esp = -1056682528, tf_ss = 0})
    at /usr/src/sys/i386/i386/trap.c:417
#9  0xc0561f90 in _mtx_lock_flags (m=0x0, opts=0, 
    file=0xc0708efe "/usr/src/sys/kern/vfs_subr.c", line=2065)
    at /usr/src/sys/kern/kern_mutex.c:247
#10 0xc05c989c in vref (vp=0x811) at /usr/src/sys/kern/vfs_subr.c:2065
#11 0xc05c2438 in namei (ndp=0xcbb67aa0) at /usr/src/sys/kern/vfs_lookup.c:161
#12 0xc05d4f63 in vn_open_cred (ndp=0xcbb67aa0, flagp=0xcbb6797c, cmode=0, 
    cred=0xc14eae80, fdidx=0) at /usr/src/sys/kern/vfs_vnops.c:191
#13 0xc05d4cf3 in vn_open (ndp=0x0, flagp=0x0, cmode=0, fdidx=0)
    at /usr/src/sys/kern/vfs_vnops.c:91
#14 0xc055ddc3 in linker_hints_lookup (
    path=0xc074d160 "/boot/kernel;/boot/kernel;/boot/modules", pathlen=12, 
    modname=0xcbb67b68 "ng_tee", modnamelen=6, verinfo=0x0)
    at /usr/src/sys/kern/kern_linker.c:1474
#15 0xc055e2da in linker_search_module (modname=0xcbb67b68 "ng_tee", modnamelen=6, 
    verinfo=0x0) at /usr/src/sys/kern/kern_linker.c:1594
#16 0xc055e49b in linker_load_module (kldname=0x0, modname=0xcbb67b68 "ng_tee", 
    parent=0x0, verinfo=0x0, lfpp=0xcbb67b64)
    at /usr/src/sys/kern/kern_linker.c:1683
#17 0xc1b49aa6 in ng_make_node () from /boot/kernel/netgraph.ko
#18 0xc1b4bb61 in ng_mkpeer () from /boot/kernel/netgraph.ko
#19 0xc1b4d9b1 in ng_generic_msg () from /boot/kernel/netgraph.ko
#20 0xc1b4d615 in ng_apply_item () from /boot/kernel/netgraph.ko
#21 0xc1b4fa2b in ngintr () from /boot/kernel/netgraph.ko
#22 0xc05e236a in swi_net (dummy=0x0) at /usr/src/sys/net/netisr.c:255
#23 0xc0554d22 in ithread_loop (arg=0xc14f5400) at /usr/src/sys/kern/kern_intr.c:544
#24 0xc0553dd2 in fork_exit (callout=0xc0554ba0 <ithread_loop>, arg=0x0, frame=0x0)
    at /usr/src/sys/kern/kern_fork.c:816

-- 
Totus tuus, Glebius.
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