PRIO_USER case, possibly also other places that deferences
p_ucred.
In the past, we insert a new process into the allproc list right
after PID allocation, and release the allproc_lock sx. Because
most content in new proc's structure is not yet initialized,
this could lead to undefined result if we do not handle PRS_NEW
with care.
The problem with PRS_NEW state is that it does not provide fine
grained information about how much initialization is done for a
new process. By defination, after PRIO_USER setpriority(), all
processes that belongs to given user should have their nice value
set to the specified value. Therefore, if p_{start,end}copy
section was done for a PRS_NEW process, we can not safely ignore
it because p_nice is in this area. On the other hand, we should
be careful on PRS_NEW processes because we do not allow non-root
users to lower their nice values, and without a successful copy
of the copy section, we can get stale values that is inherted
from the uninitialized area of the process structure.
This commit tries to close the race condition by grabbing proc
mutex *before* we release allproc_lock xlock, and do copy as
well as zero immediately after the allproc_lock xunlock. This
guarantees that the new process would have its p_copy and p_zero
sections, as well as user credential informaion initialized. In
getpriority() case, instead of grabbing PROC_LOCK for a PRS_NEW
process, we just skip the process in question, because it does
not affect the final result of the call, as the p_nice value
would be copied from its parent, and we will see it during
allproc traverse.
Other potential solutions are still under evaluation.
Discussed with: davidxu, jhb, rwatson
PR: kern/108071
MFC after: 2 weeks
acl_from_text.c. Since acl_from_text.c is the only place it
is used, we can now make this internal utility function "static."
As a bonus, acl_set_fd() no longer pulls in getpwuid() for no reason.
MFC after: 7 days
Before this fix the -h flag was ignored (i.e. setfacl
always set the ACL on the file pointed to by the symbolic
link even when the -h flag requested that the ACL be set
on the symbolic link itself).
semi-automatic style(9)
The futex stuff already differs a lot (only a small part does not differ)
from NetBSD, so we are already way off and can't apply changes from NetBSD
automatically. As we need to merge everything by hand already, we can even
make the files comply to our world order.
(external) microphone pin tend to screw it. Internal microphone (found
on several laptops) still need high VRef.
Tested by: Pietro Cerutti <pietro.cerutti@gmail.com>
lenix <irc.freenode.net>
immediately flag any page that is allocated to a OBJT_PHYS object as
unmanaged in vm_page_alloc() rather than waiting for a later call to
vm_page_unmanage(). This allows for the elimination of some uses of
the page queues lock.
Change the type of the kernel and kmem objects from OBJT_DEFAULT to
OBJT_PHYS. This allows us to take advantage of the above change to
simplify the allocation of unmanaged pages in kmem_alloc() and
kmem_malloc().
Remove vm_page_unmanage(). It is no longer used.
It is built in the same module as IPv4 multicast forwarding, i.e. ip_mroute.ko,
if and only if IPv6 support is enabled for loadable modules.
Export IPv6 forwarding structs to userland netstat(1) via sysctl(9).
- Dont "return" in linux_clone() after we forked the new process in a case
of problems.
- Move the copyout of p2->p_pid outside the emul_lock coverage in
linux_clone().
- Cache the em->pdeath_signal in a local variable and move the copyout
out of the emul_lock coverage.
- Move the free() out of the emul_shared_lock coverage in a preparation
to switch emul_lock to non-sleepable lock (mutex).
Submitted by: rdivacky
