On Thu, Apr 28, 2022 at 04:04:41PM +0200, Alexander Bluhm wrote:
> On Wed, Apr 27, 2022 at 09:16:48AM +0200, Sebastien Marie wrote:
> > Here a new diff (sorry for the delay) which add a new vnode_history_record()
> > point inside uvn_detach() (when 'uvn' object has UVM_VNODE_CANPERSIST flag
> > sets).
>
> [-- MARK -- Thu Apr 28 14:10:00 2022]
> uvn_io: start: 0x23ae1400, type VREG, use 0, write 0, hold 0, flags
> (VBIOONFREELIST)
> tag VT_UFS, ino 495247, on dev 0, 10 flags 0x100, effnlink 1, nlink 1
> mode 0100660, owner 21, group 21, size 13647873
> ==> vnode_history_print 0x23ae1400, next=6
> [3] c++[44194] usecount 2>1
> #0 0x626946ec
> [4] reaper[10898] usecount 1>1
> #0 entropy_pool0+0xf54
even if the stacktrace is somehow grabage, the "usecount 1>1" is due to VH_NOP
(no increment neither decrement), so it is the vnode_history_record() newly
added at:
@@ -323,6 +325,10 @@ uvn_detach(struct uvm_object *uobj)
* let it "stick around".
*/
if (uvn->u_flags & UVM_VNODE_CANPERSIST) {
+ extern void vnode_history_record(struct vnode *, int);
+
+ vnode_history_record(vp, 0);
+
/* won't block */
uvn_flush(uobj, 0, 0, PGO_DEACTIVATE|PGO_ALLPAGES);
goto out;
mpi@, it confirms that uvn_flush() is called without PGO_FREE for this uvn.
> [5] reaper[10898] usecount 1>0
> #0 splx+0x30
> #1 0xfffffffc
> #2 vrele+0x5c
> #3 uvn_detach+0x160
> #4 uvm_unmap_detach+0x1a4
> #5 uvm_map_teardown+0x184
> #6 uvmspace_free+0x60
> #7 uvm_exit+0x30
> #8 reaper+0x138
> #9 fork_trampoline+0x14
--
Sebastien Marie
