CVS commit: src

["Jason R Thorpe" <thorpej%netbsd.org@localhost>]

Module Name:    src
Committed By:   thorpej
Date:           Thu Apr 30 04:18:07 UTC 2020

Modified Files:
        src/sys/uvm: uvm_map.c
        src/tests/lib/libc/sys: t_futex_ops.c

Log Message:
- In uvm_voaddr_acquire(), take an extra hold on the anon lock obj.
- In uvm_voaddr_release(), if the anon ref count drops to 0, call
  uvm_anfree() rather than uvm_anon_release().  Unconditionally drop
  the anon lock, and release the extra hold on the anon lock obj.

Fixes a panic that occurs if the backing store for a futex backed by
an anon memory location is unmapped while a thread is waiting in the
futex.

Add a test case that reproduced the panic to verify that it's fixed.


To generate a diff of this commit:
cvs rdiff -u -r1.381 -r1.382 src/sys/uvm/uvm_map.c
cvs rdiff -u -r1.2 -r1.3 src/tests/lib/libc/sys/t_futex_ops.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.