Re: kern/55237

[Yorick Hardy <yorickhardy%gmail.com@localhost>]

The following reply was made to PR kern/55237; it has been noted by GNATS.

From: Yorick Hardy <yorickhardy%gmail.com@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/55237
Date: Mon, 16 Nov 2020 14:35:53 +0200

 I added the KASSERT below (is it correct?), and triggered a panic
 early during boot (it is not easily reproducible so far):
 
 [    75.787066] panic: kernel diagnostic assertion "!rw_lock_held(uobj->vmobjlock)" failed: file "/usr/src/local/sys/uvm/uvm_vnode.c", line 137
 [    75.787066] cpu0: Begin traceback...
 [    75.787066] vpanic() at netbsd:vpanic+0x156
 [    75.787066] __x86_indirect_thunk_rax() at netbsd:__x86_indirect_thunk_rax
 [    75.787066] uvn_detach() at netbsd:uvn_detach+0x51
 [    75.787066] uvm_unmap_detach() at netbsd:uvm_unmap_detach+0x7b
 [    75.787066] uvmspace_free() at netbsd:uvmspace_free+0xeb
 [    75.797068] exit1() at netbsd:exit1+0x1b8
 [    75.797068] sys_exit() at netbsd:sys_exit+0x39
 [    75.797068] syscall() at netbsd:syscall+0x23e
 [    75.797068] --- syscall (number 1) ---
 [    75.797068] netbsd:syscall+0x23e:
 [    75.797068] cpu0: End traceback...
 
 
 Index: sys/uvm/uvm_vnode.c
 ===================================================================
 RCS file: /cvsroot/src/sys/uvm/uvm_vnode.c,v
 retrieving revision 1.117
 diff -u -u -r1.117 uvm_vnode.c
 --- sys/uvm/uvm_vnode.c	16 Aug 2020 00:24:41 -0000	1.117
 +++ sys/uvm/uvm_vnode.c	16 Nov 2020 12:30:39 -0000
 @@ -134,6 +134,7 @@
  static void
  uvn_detach(struct uvm_object *uobj)
  {
 +	KASSERT(!rw_lock_held(uobj->vmobjlock));
  	vrele((struct vnode *)uobj);
  }
  
 
 -- 
 Kind regards,
 
 Yorick Hardy