obtain the memory map of the traced process. PT_VM_TIMESTAMP can be
used to check if the memory map changed since the last time to avoid
iterating over all the VM entries unnecesarily.
MFC after: 1 month
I added counters to see how often fast copying to userspace was actually
performed, which was only useful during development. Remove these
statistics now we know it to be effective.
Make CAM to stop all attached devices on system shutdown.
It allows devices to park heads, reducing stress on power loss.
Add `kern.cam.power_down` tunable and sysctl to controll it.
successfully. Continue to do this before the empty path check so that the
ENOENT returned in that case gets an empty string token in the BSM record.
MFC after: 3 days
In the current code, the locking is completely broken and may lead
easilly to deadlocks. Fix it by using the proc_mtx, linked to the
suspending thread, as lock for the operation. Keep using the
thread_lock for setting and reading the flag even if it is not entirely
necessary (atomic ops may do it as well, but this way the code is more
readable).
- Fix a deadlock within kthread_suspend().
The suspender should not sleep on a different channel wrt the suspended
thread, or, otherwise, the awaker should wakeup both. Uniform the
interface to what the kproc_* counterparts do (sleeping on the same
channel).
- Change the kthread_suspend_check() prototype.
kthread_suspend_check() always assumes curthread and must only refer to
it, so skip the thread pointer as it may be easilly mistaken.
If curthread is not a kthread, the system will panic.
In collabouration with: jhb
Tested by: Giovanni Trematerra
<giovanni dot trematerra at gmail dot com>
MFC: 2 weeks
In the case of the thread being on a sleepqueue or a turnstile, the
sched_lock was acquired (without the aid of the td_lock interface) and
the td_lock was dropped. This was going to break locking rules on other
threads willing to access to the thread (via the td_lock interface) and
modify his flags (allowed as long as the container lock was different
by the one used in sched_switch).
In order to prevent this situation, while sched_lock is acquired there
the td_lock gets blocked. [0]
- Merge the ULE's internal function thread_block_switch() into the global
thread_lock_block() and make the former semantic as the default for
thread_lock_block(). This means that thread_lock_block() will not
disable interrupts when called (and consequently thread_unlock_block()
will not re-enabled them when called). This should be done manually
when necessary.
Note, however, that ULE's thread_unblock_switch() is not reaped
because it does reflect a difference in semantic due in ULE (the
td_lock may not be necessarilly still blocked_lock when calling this).
While asymmetric, it does describe a remarkable difference in semantic
that is good to keep in mind.
[0] Reported by: Kohji Okuno
<okuno dot kohji at jp dot panasonic dot com>
Tested by: Giovanni Trematerra
<giovanni dot trematerra at gmail dot com>
MFC: 2 weeks
syscall arguments are collected before ptracestop() is called. As a
consequence, debugger cannot modify syscall or its arguments.
For i386, amd64 and ia32 on amd64 MD syscall(), reread syscall number
and arguments after ptracestop(), if debugger modified anything in the
process environment. Since procfs stopeven requires number of syscall
arguments in p_xstat, this cannot be solved by moving stop/trace point
before argument fetching.
Move the code to read arguments into separate function
fetch_syscall_args() to avoid code duplication. Note that ktrace point
for modified syscall is intentionally recorded twice, once with original
arguments, and second time with the arguments set by debugger.
PT_TO_SCX stop is executed after cpu_syscall_set_retval() already.
Reported by: Ali Polatel <alip exherbo org>
Briefly discussed with: jhb
MFC after: 3 weeks
stopped and debugger may modify or drop the signal. After the changes to
keep process-targeted signals on the process sigqueue, another thread
may note the old signal on the queue and act before the thread removes
changed or dropped signal from the process queue. Since process is
traced, it usually gets stopped. Or, if the same signal is delivered
while process was stopped, the thread may erronously remove it,
intending to remove the original signal.
Remove the signal from the queue before notifying the debugger. Restore
the siginfo to the head of sigqueue when signal is allowed to be
delivered to the debugee, using newly introduced KSI_HEAD ksiginfo_t
flag. This preserves required order of delivery. Always restore the
unchanged signal on the curthread sigqueue, not to the process queue,
since the thread is about to get it anyway, because sigmask cannot be
changed.
Handle failure of reinserting the siginfo into the queue by falling
back to sq_kill method, calling sigqueue_add with NULL ksi.
If debugger changed the signal to be delivered, use sigqueue_add()
with NULL ksi instead of only setting sq_signals bit.
Reported by: Gardner Bell <gbell72 rogers com>
Analyzed and first version of fix by: Tijl Coosemans <tijl coosemans org>
PR: 142757
Reviewed by: davidxu
MFC after: 2 weeks
count) while vnode is exclusively locked.
The code for vput(9), vrele(9) and vunref(9) is merged.
In collaboration with: pho
Reviewed by: alc
MFC after: 3 weeks
whether to use source address selection (default) or the primary
jail address for unbound outgoing connections.
This is intended to be used by people upgrading from single-IP
jails to multi-IP jails but not having to change firewall rules,
application ACLs, ... but to force their connections (unless
otherwise changed) to the primry jail IP they had been used for
years, as well as for people prefering to implement similar policies.
Note that for IPv6, if configured incorrectly, this might lead to
scope violations, which single-IPv6 jails could as well, as by the
design of jails. [1]
Reviewed by: jamie, hrs (ipv6 part)
Pointed out by: hrs [1]
MFC After: 2 weeks
Asked for by: Jase Thew (bazerka beardz.net)
of allocating what ever the user asks for up to "ngroups_max + 1". On
systems with large values of kern.ngroups this will be more efficient.
The now redundant check that the array is large enough in
kern_getgroups() is deliberate to allow this change to be merged to
stable/8 without breaking potential third party consumers of the API.
Reported by: bde
MFC after: 28 days
kern.ngroups+1. kern.ngroups can range from NGROUPS_MAX=1023 to
INT_MAX-1. Given that the Windows group limit is 1024, this range
should be sufficient for most applications.
MFC after: 1 month
- name some columns more closely to the user space variables,
as we do for host.* or allow.* (in the listing) already.
- print pr_childmax (children.max).
- prefix hex values with 0x.
MFC after: 3 weeks
When renaming a directory it passes through several intermediate
states. First its new name will be created causing it to have two
names (from possibly different parents). Next, if it has different
parents, its value of ".." will be changed from pointing to the old
parent to pointing to the new parent. Concurrently, its old name
will be removed bringing it back into a consistent state. When fsck
encounters an extra name for a directory, it offers to remove the
"extraneous hard link"; when it finds that the names have been
changed but the update to ".." has not happened, it offers to rewrite
".." to point at the correct parent. Both of these changes were
considered unexpected so would cause fsck in preen mode or fsck in
background mode to fail with the need to run fsck manually to fix
these problems. Fsck running in preen mode or background mode now
corrects these expected inconsistencies that arise during directory
rename. The functionality added with this update is used by fsck
running in background mode to make these fixes.
Solution:
This update adds three new fsck sysctl commands to support background
fsck in correcting expected inconsistencies that arise from incomplete
directory rename operations. They are:
setcwd(dirinode) - set the current directory to dirinode in the
filesystem associated with the snapshot.
setdotdot(oldvalue, newvalue) - Verify that the inode number for ".."
in the current directory is oldvalue then change it to newvalue.
unlink(nameptr, oldvalue) - Verify that the inode number associated
with nameptr in the current directory is oldvalue then unlink it.
As with all other fsck sysctls, these new ones may only be used by
processes with appropriate priviledge.
Reported by: jeff
Security issues: rwatson
r198561 | thompsa | 2009-10-28 15:25:22 -0600 (Wed, 28 Oct 2009) | 4 lines
Allow a scratch buffer to be set in order to be able to use setenv() while
booting, before dynamic kenv is running. A few platforms implement their own
scratch+sprintf handling to save data from the boot environment.
While the name is pretentious, a good explanation of its targets is
reported in this 17 months old presentation e-mail:
http://lists.freebsd.org/pipermail/freebsd-arch/2008-August/008452.html
In order to implement it, the sq_type in sleepqueues is mandatory and not
only compiled along with INVARIANTS option. Additively, a new sleepqueue
function, sleepq_type() is added, returning the type of the sleepqueue
linked to a wchan.
Three new sysctls are added in order to configure the thread:
debug.deadlkres.slptime_threshold
debug.deadlkres.blktime_threshold
debug.deadlkres.sleepfreq
rappresenting the thresholds for sleep and block time that will lead to
a deadlock matching (when exceeded), while the sleepfreq rappresents the
number of seconds between 2 consecutive thread runnings.
In order to enable the deadlock resolver thread recompile your kernel
with the option DEADLKRES.
Reviewed by: jeff
Tested by: pho, Giovanni Trematerra
Sponsored by: Nokia Incorporated, Sandvine Incorporated
MFC after: 2 weeks
is not cleaned up on the wakeup but reset.
This is harmless mostly because td_slptick (and ki_slptime from
userland) should be analyzed only with the assumption that the thread
is actually sleeping (thus while the td_slptick is correctly set) but
without this invariant the number is nomore consistent.
- Move td_slptick from u_int to int in order to follow 'ticks' signedness
and wrap up accordingly [0]
[0] Submitted by: emaste
Sponsored by: Sandvine Incorporated
MFC 1 week
sleeps/timeout may have left spourious lk_exslpfail counts on, so clean
it up even when accessing a shared queue acquisition, giving to
lk_exslpfail the value of 'upper limit'.
In the worst case scenario, infact (mixed
interruptible sleep / LK_SLEEPFAIL waiters) what may happen is that both
queues are awaken even if that's not necessary, but still no harm.
Reported by: Lucius Windschuh <lwindschuh at googlemail dot com>
Reviewed by: kib
Tested by: pho, Lucius Windschuh <lwindschuh at googlemail dot com>
now type sema_t is a structure which can be put in a shared memory area,
and multiple processes can operate it concurrently.
User can either use mmap(MAP_SHARED) + sem_init(pshared=1) or use sem_open()
to initialize a shared semaphore.
Named semaphore uses file system and is located in /tmp directory, and its
file name is prefixed with 'SEMD', so now it is chroot or jail friendly.
In simplist cases, both for named and un-named semaphore, userland code
does not have to enter kernel to reduce/increase semaphore's count.
The semaphore is designed to be crash-safe, it means even if an application
is crashed in the middle of operating semaphore, the semaphore state is
still safely recovered by later use, there is no waiter counter maintained
by userland code.
The main semaphore code is in libc and libthr only has some necessary stubs,
this makes it possible that a non-threaded application can use semaphore
without linking to thread library.
Old semaphore implementation is kept libc to maintain binary compatibility.
The kernel ksem API is no longer used in the new implemenation.
Discussed on: threads@
It looks like I didn't implement this when I imported MPSAFE TTY.
Applications like mail(1) still use this. I think it's conceptually bad.
Tested by: Pete French <petefrench ticketswitch com>
MFC after: 2 weeks
processes to share semaphore by using shared memory area, in simplest case,
only one atomic operation is needed in userland, waiter flag is maintained by
kernel and userland only checks the flag, if the flag is set, user code enters
kernel and does a wakeup() call.
Move type definitions into file _umtx.h to minimize compiling time.
Also type names need to be prefixed with underline character, this would reduce
name conflict (still in progress).
r195175. Remove all definitions, documentation, and usage.
fifo_misc.c:
Remove all kqueue tests as fifo_io.c performs all those that
would have remained.
Reviewed by: rwatson
MFC after: 3 weeks
X-MFC note: don't change vlan_link_state() function signature
or equial then PSOCK, not less or equial. Higher priority has lesser
numerical value.
Existing test does not allow for swapout of the thread waiting for
advisory lock, for exiting child or sleeping for timeout. On the other
hand, high-priority waiters of VFS/VM events can be swapped out.
Tested by: pho
Reviewed by: jhb
MFC after: 1 week
