NetBSD/sys/miscfs/kernfs
hannken 2b6ec89863 The current implementation of vn_lock() is racy. Modification of
the vnode operations vector for active vnodes is unsafe because it
is not known whether deadfs or the original file system will be
called.

- Pass down LK_RETRY to the lock operation (hint for deadfs only).

- Change deadfs lock operation to return ENOENT if LK_RETRY is unset.

- Change all other lock operations to check for dead vnode once
  the vnode is locked and unlock and return ENOENT in this case.

With these changes in place vnode lock operations will never succeed
after vclean() has marked the vnode as VI_XLOCK and before vclean()
has changed the operations vector.

Adresses PR kern/37706 (Forced unmount of file systems is unsafe)

Discussed on tech-kern.

Welcome to 6.99.33
2014-02-27 16:51:37 +00:00
..
Makefile
files.kernfs
kernfs.h remove KAME IPSEC, replaced by FAST_IPSEC 2012-03-22 20:34:37 +00:00
kernfs_subr.c The current implementation of vn_lock() is racy. Modification of 2014-02-27 16:51:37 +00:00
kernfs_vfsops.c Ensure that the top level sysctl nodes (kern, vfs, net, ...) exist before 2014-02-25 18:30:08 +00:00
kernfs_vnops.c Change vnode operation lookup to return the resulting vnode *vpp unlocked. 2014-02-07 15:29:20 +00:00