of devvp becomes VBAD, which UFS incorrectly interprets as snapshot
vnode, which in turns causes panic. Fix it by replacing '!= VCHR'
with '== VREG'.
With this fix in place, you should no longer be able to panic the system
by removing a device with an UFS filesystem mounted from it - assuming
you don't use softupdates.
Reviewed by: kib
Tested by: pho
Approved by: rwatson (mentor)
Sponsored by: FreeBSD Foundation
Back in 1.1 of kern_sysctl.c the sysctl() routine wired the "old" userland
buffer for most sysctls (everything except kern.vnode.*). I think to prevent
issues with wiring too much memory it used a 'memlock' to serialize all
sysctl(2) invocations, meaning that only one user buffer could be wired at
a time. In 5.0 the 'memlock' was converted to an sx lock and renamed to
'sysctl lock'. However, it still only served the purpose of serializing
sysctls to avoid wiring too much memory and didn't actually protect the
sysctl tree as its name suggested. These changes expand the lock to actually
protect the tree.
Later on in 5.0, sysctl was changed to not wire buffers for requests by
default (sysctl_handle_opaque() will still wire buffers larger than a single
page, however). As a result, user buffers are no longer wired as often.
However, many sysctl handlers still wire user buffers, so it is still
desirable to serialize userland sysctl requests. Kernel sysctl requests
are allowed to run in parallel, however.
- Expose sysctl_lock()/sysctl_unlock() routines to exclusively lock the
sysctl tree for a few places outside of kern_sysctl.c that manipulate
the sysctl tree directly including the kernel linker and vfs_register().
- sysctl_register() and sysctl_unregister() require the caller to lock
the sysctl lock using sysctl_lock() and sysctl_unlock(). The rest of
the public sysctl API manage the locking internally.
- Add a locked variant of sysctl_remove_oid() for internal use so that
external uses of the API do not need to be aware of locking requirements.
- The kernel linker no longer needs Giant when manipulating the sysctl
tree.
- Add a missing break to the loop in vfs_register() so that we stop looking
at the sysctl MIB once we have changed it.
MFC after: 1 month
in fallback_mount() function.
Add a comment to indicate that the fallback_mount() function
should eventually go away.
Submitted by: Jaakko Heinonen <jh saunalahti fi>
sysctls during a linker file unload. We drop the lock when doing similar
operations during a linker file load. To close races, clear the LINKED
flag before dropping the lock so that the linker file is no longer visible
to userland.
MFC after: 1 week
o change tdma packet drop msg when ack required to ATH_DEBUG_TDMA
(ATH_DEBUG_XMIT is too noisy)
o add a debug msg for raw packet drop due to interface down/invalid
o add stats for these two cases
o explain how another drop case is handled
IEEE80211_KEY_DEVKEY
o fix channel power printing (they are signed values)
o add show statab to dump a node table and automatically dump the sta
table of a com structure with /s
