(unknown charset) [Fwd: cvs commit: src/sys/kern sys_pipe.c]

I believe that the attached commit addresses the "panic: sleeping thread
owns a mutex" problem reported by Kris and another related problem
reported a few days earlier.  The earlier problem report included the
following stack trace:

Sleeping on "objtrm" with the following non-sleepablelocks held:
exclusive sleep mutex system map r = 0 (0xfffff80067e92098) locked _at_
/usr/src/sys/vm/vm_map.c:2192
lock order reversal
 1st 0xfffff80067e92098 system map (system map) _at_
/usr/src/sys/vm/vm_map.c:2192
 2nd 0xc0354d70 Giant (Giant) _at_ /usr/src/sys/kern/kern_synch.c:312
Stack backtrace:
_mtx_lock_flags() at _mtx_lock_flags+0xa0
msleep() at msleep+0x6a8
vm_object_pip_wait() at vm_object_pip_wait+0x48
vm_object_terminate() at vm_object_terminate+0x30
vm_object_deallocate() at vm_object_deallocate+0x374
vm_map_entry_delete() at vm_map_entry_delete+0x3c
vm_map_delete() at vm_map_delete+0x32c
vm_map_remove() at vm_map_remove+0x44
kmem_free() at kmem_free+0x20
pipe_free_kmem() at pipe_free_kmem+0x98
pipeclose() at pipeclose+0x124
pipe_close() at pipe_close+0x20
fdrop_locked() at fdrop_locked+0x134
fdrop() at fdrop+0x20
closef() at closef+0x1f8
close() at close+0x168
syscall() at syscall+0x2ac
-- syscall (6, FreeBSD ELF64, close) %o7=0x10706c --

attached mail follows:

alc         2003/07/30 11:55:04 PDT

  FreeBSD src repository

  Modified files:
    sys/kern             sys_pipe.c 
  Log:
  The introduction of vm object locking has caused witness to reveal
  a long-standing mistake in the way a portion of a pipe's KVA is
  allocated.  Specifically, kmem_alloc_pageable() is inappropriate
  for use in the "direct" case because it allows a preceding vm map entry
  and vm object to be extended to support the new KVA allocation.
  However, the direct case KVA allocation should not have a backing
  vm object.  This is corrected by using kmem_alloc_nofault().
  
  Submitted by:   tegge (with the above explanation by me)
  
  Revision  Changes    Path
  1.140     +1 -1      src/sys/kern/sys_pipe.c