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396 Commits

Author SHA1 Message Date
Mateusz Guzik
5afb134c32 vfs: add vrefact, to be used when the vnode has to be already active
This allows blind increment of relevant counters which under contention
is cheaper than inc-not-zero loops at least on amd64.

Use it in some of the places which are guaranteed to see already active
vnodes.

Reviewed by:	kib (previous version)
2016-12-12 15:37:11 +00:00
Konstantin Belousov
643f6f47fd Add PROC_TRAPCAP procctl(2) controls and global sysctl kern.trap_enocap.
Both can be used to cause processes in capability mode to receive
SIGTRAP when ENOTCAPABLE or ECAPMODE errors are returned from
syscalls.

Idea by:	emaste
Reviewed by:	oshogbo (previous version), emaste
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D7965
2016-09-21 08:23:33 +00:00
Ed Maste
69a2875821 Renumber license clauses in sys/kern to avoid skipping #3 2016-09-15 13:16:20 +00:00
Mark Johnston
e5574e0966 Don't set P2_PTRACE_FSTP in a process that invokes ptrace(PT_TRACE_ME).
Such processes are stopped synchronously by a direct call to
ptracestop(SIGTRAP) upon exec. P2_PTRACE_FSTP causes the exec()ing thread
to suspend itself while waiting for a SIGSTOP that never arrives.

Reviewed by:	kib
MFC after:	3 days
Differential Revision:	https://reviews.freebsd.org/D7576
2016-08-19 17:57:14 +00:00
Konstantin Belousov
e69ba32f88 Remove mention of the Giant from the fork_return() description.
Making emphasis on this lock in the core function comment is confusing
for the modern kernel.

Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
2016-08-03 07:10:09 +00:00
Konstantin Belousov
b7a25e63b6 When a debugger attaches to the process, SIGSTOP is sent to the
target.  Due to a way issignal() selects the next signal to deliver
and report, if the simultaneous or already pending another signal
exists, that signal might be reported by the next waitpid(2) call.
This causes minor annoyance for debuggers, which must be prepared to
take any signal as the first event, then filter SIGSTOP later.

More importantly, for tools like gcore(1), which attach and then
detach without processing events, SIGSTOP might leak to be delivered
after PT_DETACH.  This results in the process being unintentionally
stopped after detach, which is fatal for automatic tools.

The solution is to force SIGSTOP to be the first signal reported after
the attach.  Attach code is modified to set P2_PTRACE_FSTP to indicate
that the attaching ritual was not yet finished, and issignal() prefers
SIGSTOP in that condition.  Also, the thread which handles
P2_PTRACE_FSTP is made to guarantee to own p_xthread during the first
waitpid(2).  All that ensures that SIGSTOP is consumed first.

Additionally, if P2_PTRACE_FSTP is still set on detach, which means
that waitpid(2) was not called at all, SIGSTOP is removed from the
queue, ensuring that the process is resumed on detach.

In issignal(), when acting on STOPing signals, remove the signal from
queue before suspending.  Otherwise parallel attach could result in
ptracestop() acting on that STOP as if it was the STOP signal from the
attach.  Then SIGSTOP from attach leaks again.

As a minor refactoring, some bits of the common attach code is moved
to new helper proc_set_traced().

Reported by:	markj
Reviewed by:	jhb, markj
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Differential revision:	https://reviews.freebsd.org/D7256
2016-07-28 08:41:13 +00:00
John Baldwin
fc4f075a1a Add PTRACE_VFORK to trace vfork events.
First, PL_FLAG_FORKED events now also set a PL_FLAG_VFORKED flag when
the new child was created via vfork() rather than fork().  Second, a
new PL_FLAG_VFORK_DONE event can now be enabled via the PTRACE_VFORK
event mask.  This new stop is reported after the vfork parent resumes
due to the child calling exit or exec.  Debuggers can use this stop to
reinsert breakpoints in the vfork parent process before it resumes.

Reviewed by:	kib
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D7045
2016-07-18 14:53:55 +00:00
John Baldwin
8d570f64aa Add a mask of optional ptrace() events.
ptrace() now stores a mask of optional events in p_ptevents.  Currently
this mask is a single integer, but it can be expanded into an array of
integers in the future.

Two new ptrace requests can be used to manipulate the event mask:
PT_GET_EVENT_MASK fetches the current event mask and PT_SET_EVENT_MASK
sets the current event mask.

The current set of events include:
- PTRACE_EXEC: trace calls to execve().
- PTRACE_SCE: trace system call entries.
- PTRACE_SCX: trace syscam call exits.
- PTRACE_FORK: trace forks and auto-attach to new child processes.
- PTRACE_LWP: trace LWP events.

The S_PT_SCX and S_PT_SCE events in the procfs p_stops flags have
been replaced by PTRACE_SCE and PTRACE_SCX.  PTRACE_FORK replaces
P_FOLLOW_FORK and PTRACE_LWP replaces P2_LWP_EVENTS.

The PT_FOLLOW_FORK and PT_LWP_EVENTS ptrace requests remain for
compatibility but now simply toggle corresponding flags in the
event mask.

While here, document that PT_SYSCALL, PT_TO_SCE, and PT_TO_SCX both
modify the event mask and continue the traced process.

Reviewed by:	kib
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D7044
2016-07-15 15:32:09 +00:00
Konstantin Belousov
9e590ff04b When filt_proc() removes event from the knlist due to the process
exiting (NOTE_EXIT->knlist_remove_inevent()), two things happen:
- knote kn_knlist pointer is reset
- INFLUX knote is removed from the process knlist.
And, there are two consequences:
- KN_LIST_UNLOCK() on such knote is nop
- there is nothing which would block exit1() from processing past the
  knlist_destroy() (and knlist_destroy() resets knlist lock pointers).
Both consequences result either in leaked process lock, or
dereferencing NULL function pointers for locking.

Handle this by stopping embedding the process knlist into struct proc.
Instead, the knlist is allocated together with struct proc, but marked
as autodestroy on the zombie reap, by knlist_detach() function.  The
knlist is freed when last kevent is removed from the list, in
particular, at the zombie reap time if the list is empty.  As result,
the knlist_remove_inevent() is no longer needed and removed.

Other changes:

In filt_procattach(), clear NOTE_EXEC and NOTE_FORK desired events
from kn_sfflags for knote registered by kernel to only get NOTE_CHILD
notifications.  The flags leak resulted in excessive
NOTE_EXEC/NOTE_FORK reports.

Fix immediate note activation in filt_procattach().  Condition should
be either the immediate CHILD_NOTE activation, or immediate NOTE_EXIT
report for the exiting process.

In knote_fork(), do not perform racy check for KN_INFLUX before kq
lock is taken.  Besides being racy, it did not accounted for notes
just added by scan (KN_SCAN).

Some minor and incomplete style fixes.

Analyzed and tested by:	Eric Badger <eric@badgerio.us>
Reviewed by:	jhb
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Approved by:	re (gjb)
Differential revision:	https://reviews.freebsd.org/D6859
2016-06-27 21:52:17 +00:00
Konstantin Belousov
5c2cf81845 Update comments for the MD functions managing contexts for new
threads, to make it less confusing and using modern kernel terms.

Rename the functions to reflect current use of the functions, instead
of the historic KSE conventions:
  cpu_set_fork_handler -> cpu_fork_kthread_handler (for kthreads)
  cpu_set_upcall -> cpu_copy_thread (for forks)
  cpu_set_upcall_kse -> cpu_set_upcall (for new threads creation)

Reviewed by:	jhb (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
Approved by:	re (hrs)
Differential revision:	https://reviews.freebsd.org/D6731
2016-06-16 12:05:44 +00:00
Mariusz Zaborski
b3a734483e Introduce the PD_CLOEXEC for pdfork(2).
Reviewed by:	mjg
2016-06-08 02:09:14 +00:00
Konstantin Belousov
93ccd6bf87 Get rid of struct proc p_sched and struct thread td_sched pointers.
p_sched is unused.

The struct td_sched is always co-allocated with the struct thread,
except for the thread0.  Avoid useless indirection, instead calculate
td_sched location using simple pointer arithmetic in td_get_sched(9).
For thread0, which is statically allocated, create a structure to
emulate layout of the dynamic allocation.

Reviewed by:	jhb (previous version)
Sponsored by:	The FreeBSD Foundation
Differential revision:	https://reviews.freebsd.org/D6711
2016-06-05 17:04:03 +00:00
Pedro F. Giffuni
e3043798aa sys/kern: spelling fixes in comments.
No functional change.
2016-04-29 22:15:33 +00:00
Konstantin Belousov
db57c70a5b Rename P_KTHREAD struct proc p_flag to P_KPROC.
I left as is an apparent bug in ntoskrnl_var.h:AT_PASSIVE_LEVEL()
definition.

Suggested by:	jhb
Sponsored by:	The FreeBSD Foundation
2016-02-09 16:30:16 +00:00
John Baldwin
fb1f4582ff Call kthread_exit() rather than kproc_exit() for a premature kthread exit.
Kernel threads (and processes) are supposed to call kthread_exit() (or
kproc_exit()) to terminate.  However, the kernel includes a fallback in
fork_exit() to force a kthread exit if a kernel thread's "main" routine
returns.  This fallback was added back when the kernel only had processes
and was not updated to call kthread_exit() instead of kproc_exit() when
threads were added to the kernel.

This mistake was particular exciting when the errant thread belonged to
proc0.  Due to the missing P_KTHREAD flag the fallback did not kick in
and instead tried to return to userland via whatever garbage was in the
trapframe.  With P_KTHREAD set it tried to terminate proc0 resulting in
other amusements.

PR:		204999
MFC after:	1 week
2016-02-08 23:11:23 +00:00
Mateusz Guzik
0c829a301d fork: ansify sys_pdfork
No functional changes.
2016-02-06 09:01:03 +00:00
Konstantin Belousov
4732ae438a Guard against runnable td2 exiting and than being reused for unrelated
process when the parent sleeps waiting for the debugger attach on
fork.

Diagnosed and reviewed by:	mjg
Sponsored by:	The FreeBSD Foundation
2016-02-04 10:49:34 +00:00
Mateusz Guzik
813361c140 fork: plug a use after free of the returned process
fork1 required its callers to pass a pointer to struct proc * which would
be set to the new process (if any). procdesc and racct manipulation also
used said pointer.

However, the process could have exited prior to do_fork return and be
automatically reaped, thus making this a use-after-free.

Fix the problem by letting callers indicate whether they want the pid or
the struct proc, return the process in stopped state for the latter case.

Reviewed by:	kib
2016-02-04 04:25:30 +00:00
Mateusz Guzik
33fd9b9a2b fork: pass arguments to fork1 in a dedicated structure
Suggested by:	kib
2016-02-04 04:22:18 +00:00
John Baldwin
5fcfab6e32 Add ptrace(2) reporting for LWP events.
Add two new LWPINFO flags: PL_FLAG_BORN and PL_FLAG_EXITED for reporting
thread creation and destruction. Newly created threads will stop to report
PL_FLAG_BORN before returning to userland and exiting threads will stop to
report PL_FLAG_EXIT before exiting completely. Both of these events are
only enabled and reported if PT_LWP_EVENTS is enabled on a process.
2015-12-29 23:25:26 +00:00
Mark Johnston
3616095801 Fix style issues around existing SDT probes.
- Use SDT_PROBE<N>() instead of SDT_PROBE(). This has no functional effect
  at the moment, but will be needed for some future changes.
- Don't hardcode the module component of the probe identifier. This is
  set automatically by the SDT framework.

MFC after:	1 week
2015-12-16 23:39:27 +00:00
Ed Schouten
aff5735784 Add a way to distinguish between forking and thread creation in schedtail.
For CloudABI we need to initialize the registers of new threads
differently based on whether the thread got created through a fork or
through simple thread creation.

Add a flag, TDP_FORKING, that is set by do_fork() and cleared by
fork_exit(). This can be tested against in schedtail.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D3973
2015-10-22 09:33:34 +00:00
Konstantin Belousov
d8f3dc7871 If falloc_caps() failed, cleanup needs to be performed. This is a bug
in r289026.

Sponsored by:	The FreeBSD Foundation
2015-10-16 14:55:39 +00:00
Konstantin Belousov
4b48959f9f Enforce the maxproc limitation before allocating struct proc, initial
struct thread and kernel stack for the thread.  Otherwise, a load
similar to a fork bomb would exhaust KVA and possibly kmem, mostly due
to the struct proc being type-stable.

The nprocs counter is changed from being protected by allproc_lock sx
to be an atomic variable.  Note that ddb/db_ps.c:db_ps() use of nprocs
was unsafe before, and is still unsafe, but it seems that the only
possible undesired consequence is the harmless warning printed when
allproc linked list length does not match nprocs.

Diagnosed by:	Svatopluk Kraus <onwahe@gmail.com>
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2015-10-08 11:07:09 +00:00
John Baldwin
189ac973de Fix various edge cases related to system call tracing.
- Always set td_dbg_sc_* when P_TRACED is set on system call entry
  even if the debugger is not tracing system call entries.  This
  ensures the fields are valid when reporting other stops that
  occur at system call boundaries such as for PT_FOLLOW_FORKS or
  when only tracing system call exits.
- Set TDB_SCX when reporting the stop for a new child process in
  fork_return().  This causes the event to be reported as a system
  call exit.
- Report a system call exit event in fork_return() for new threads in
  a traced process.
- Copy td_dbg_sc_* to new threads instead of zeroing.  This ensures
  that td_dbg_sc_code in particular will report the system call that
  created the new thread or process when it reports a system call
  exit event in fork_return().
- Add new ptrace tests to verify that new child processes and threads
  report system call exit events with a valid pl_syscall_code via
  PT_LWPINFO.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D3822
2015-10-06 19:29:05 +00:00
Andriy Gapon
2f2f522b5d save some bytes by using more concise SDT_PROBE<n> instead of SDT_PROBE
SDT_PROBE requires 5 parameters whereas SDT_PROBE<n> requires n parameters
where n is typically smaller than 5.

Perhaps SDT_PROBE should be made a private implementation detail.

MFC after:	20 days
2015-09-28 12:14:16 +00:00
Konstantin Belousov
edc8222303 Make kstack_pages a tunable on arm, x86, and powepc. On i386, the
initial thread stack is not adjusted by the tunable, the stack is
allocated too early to get access to the kernel environment. See
TD0_KSTACK_PAGES for the thread0 stack sizing on i386.

The tunable was tested on x86 only.  From the visual inspection, it
seems that it might work on arm and powerpc.  The arm
USPACE_SVC_STACK_TOP and powerpc USPACE macros seems to be already
incorrect for the threads with non-default kstack size.  I only
changed the macros to use variable instead of constant, since I cannot
test.

On arm64, mips and sparc64, some static data structures are sized by
KSTACK_PAGES, so the tunable is disabled.

Sponsored by:	The FreeBSD Foundation
MFC after:	2 week
2015-08-10 17:18:21 +00:00
Ed Schouten
6236e71bfe Fix accidental line wrapping introduced in r286122. 2015-07-31 10:46:45 +00:00
Ed Schouten
367a13f905 Limit rights on process descriptors.
On CloudABI, the rights bits returned by cap_rights_get() match up with
the operations that you can actually perform on the file descriptor.

Limiting the rights is good, because it makes it easier to get uniform
behaviour across different operating systems. If process descriptors on
FreeBSD would suddenly gain support for any new file operation, this
wouldn't become exposed to CloudABI processes without first extending
the rights.

Extend fork1() to gain a 'struct filecaps' argument that allows you to
construct process descriptors with custom rights. Use this in
cloudabi_sys_proc_fork() to limit the rights to just fstat() and
pdwait().

Obtained from:	https://github.com/NuxiNL/freebsd
2015-07-31 10:21:58 +00:00
Adrian Chadd
6520495abc Add an initial NUMA affinity/policy configuration for threads and processes.
This is based on work done by jeff@ and jhb@, as well as the numa.diff
patch that has been circulating when someone asks for first-touch NUMA
on -10 or -11.

* Introduce a simple set of VM policy and iterator types.
* tie the policy types into the vm_phys path for now, mirroring how
  the initial first-touch allocation work was enabled.
* add syscalls to control changing thread and process defaults.
* add a global NUMA VM domain policy.
* implement a simple cascade policy order - if a thread policy exists, use it;
  if a process policy exists, use it; use the default policy.
* processes inherit policies from their parent processes, threads inherit
  policies from their parent threads.
* add a simple tool (numactl) to query and modify default thread/process
  policities.
* add documentation for the new syscalls, for numa and for numactl.
* re-enable first touch NUMA again by default, as now policies can be
  set in a variety of methods.

This is only relevant for very specific workloads.

This doesn't pretend to be a final NUMA solution.

The previous defaults in -HEAD (with MAXMEMDOM set) can be achieved by
'sysctl vm.default_policy=rr'.

This is only relevant if MAXMEMDOM is set to something other than 1.
Ie, if you're using GENERIC or a modified kernel with non-NUMA, then
this is a glorified no-op for you.

Thank you to Norse Corp for giving me access to rather large
(for FreeBSD!) NUMA machines in order to develop and verify this.

Thank you to Dell for providing me with dual socket sandybridge
and westmere v3 hardware to do NUMA development with.

Thank you to Scott Long at Netflix for providing me with access
to the two-socket, four-domain haswell v3 hardware.

Thank you to Peter Holm for running the stress testing suite
against the NUMA branch during various stages of development!

Tested:

* MIPS (regression testing; non-NUMA)
* i386 (regression testing; non-NUMA GENERIC)
* amd64 (regression testing; non-NUMA GENERIC)
* westmere, 2 socket (thankyou norse!)
* sandy bridge, 2 socket (thankyou dell!)
* ivy bridge, 2 socket (thankyou norse!)
* westmere-EX, 4 socket / 1TB RAM (thankyou norse!)
* haswell, 2 socket (thankyou norse!)
* haswell v3, 2 socket (thankyou dell)
* haswell v3, 2x18 core (thankyou scott long / netflix!)

* Peter Holm ran a stress test suite on this work and found one
  issue, but has not been able to verify it (it doesn't look NUMA
  related, and he only saw it once over many testing runs.)

* I've tested bhyve instances running in fixed NUMA domains and cpusets;
  all seems to work correctly.

Verified:

* intel-pcm - pcm-numa.x and pcm-memory.x, whilst selecting different
  NUMA policies for processes under test.

Review:

This was reviewed through phabricator (https://reviews.freebsd.org/D2559)
as well as privately and via emails to freebsd-arch@.  The git history
with specific attributes is available at https://github.com/erikarn/freebsd/
in the NUMA branch (https://github.com/erikarn/freebsd/compare/local/adrian_numa_policy).

This has been reviewed by a number of people (stas, rpaulo, kib, ngie,
wblock) but not achieved a clear consensus.  My hope is that with further
exposure and testing more functionality can be implemented and evaluated.

Notes:

* The VM doesn't handle unbalanced domains very well, and if you have an overly
  unbalanced memory setup whilst under high memory pressure, VM page allocation
  may fail leading to a kernel panic.  This was a problem in the past, but it's
  much more easily triggered now with these tools.

* This work only controls the path through vm_phys; it doesn't yet strongly/predictably
  affect contigmalloc, KVA placement, UMA, etc.  So, driver placement of memory
  isn't really guaranteed in any way.  That's next on my plate.

Sponsored by:	Norse Corp, Inc.; Dell
2015-07-11 15:21:37 +00:00
Mateusz Guzik
f6f6d24062 Implement lockless resource limits.
Use the same scheme implemented to manage credentials.

Code needing to look at process's credentials (as opposed to thred's) is
provided with *_proc variants of relevant functions.

Places which possibly had to take the proc lock anyway still use the proc
pointer to access limits.
2015-06-10 10:48:12 +00:00
Mateusz Guzik
4ea6a9a28f Generalised support for copy-on-write structures shared by threads.
Thread credentials are maintained as follows: each thread has a pointer to
creds and a reference on them. The pointer is compared with proc's creds on
userspace<->kernel boundary and updated if needed.

This patch introduces a counter which can be compared instead, so that more
structures can use this scheme without adding more comparisons on the boundary.
2015-06-10 10:43:59 +00:00
John Baldwin
515b7a0b97 Add KTR tracing for some MI ptrace events.
Differential Revision:	https://reviews.freebsd.org/D2643
Reviewed by:	kib
2015-05-25 22:13:22 +00:00
Mateusz Guzik
edf1796d3e Fix up panics when fork fails due to hitting proc limit
The function clearning credentials on failure asserts the process is a
zombie, which is not true when fork fails.

Changing creds to NULL is unnecessary, but is still being done for
consistency with other code.

Pointy hat: mjg
Reported by: pho
2015-05-06 21:03:19 +00:00
Mateusz Guzik
90f54cbfeb fd: remove filedesc argument from fdclose
Just accept a thread instead. This makes it consistent with fdalloc.

No functional changes.
2015-04-11 15:40:28 +00:00
Mateusz Guzik
ffb34484ee cred: add proc_set_cred_init helper
proc_set_cred_init can be used to set first credentials of a new
process.

Update proc_set_cred assertions so that it only expects already used
processes.

This fixes panics where p_ucred of a new process happens to be non-NULL.

Reviewed by:	kib
2015-03-21 20:24:54 +00:00
Mateusz Guzik
12cec311e6 fork: assign refed credentials earlier
Prior to this change the kernel would take p1's credentials and assign
them tempororarily to p2. But p1 could change credentials at that time
and in effect give us a use-after-free.

No objections from: kib
2015-03-21 20:24:03 +00:00
Mateusz Guzik
daf63fd2f9 cred: add proc_set_cred helper
The goal here is to provide one place altering process credentials.

This eases debugging and opens up posibilities to do additional work when such
an action is performed.
2015-03-16 00:10:03 +00:00
Konstantin Belousov
677258f7e7 Add procctl(2) PROC_TRACE_CTL command to enable or disable debugger
attachment to the process.  Note that the command is not intended to
be a security measure, rather it is an obfuscation feature,
implemented for parity with other operating systems.

Discussed with:	jilles, rwatson
Man page fixes by:	rwatson
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2015-01-18 15:13:11 +00:00
Konstantin Belousov
237623b028 Add a facility for non-init process to declare itself the reaper of
the orphaned descendants.  Base of the API is modelled after the same
feature from the DragonFlyBSD.

Requested by:	bapt
Reviewed by:	jilles (previous version)
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	3 weeks
2014-12-15 12:01:42 +00:00
Konstantin Belousov
6ddcc23386 Add facility to stop all userspace processes. The supposed use of the
feature is to quisce the system before suspend.

Stop is implemented by reusing the thread_single(9) with the special
mode SINGLE_ALLPROC.  SINGLE_ALLPROC differs from the existing
single-threading modes by allowing (requiring) caller to operate on
other process.  Interruptible sleeps for !TDF_SBDRY threads are
suspended like SIGSTOP does it, instead of aborting the sleep, like
SINGLE_NO_EXIT, to avoid spurious EINTRs on resume.

Provide debugging sysctl debug.stop_all_proc, which causes total stop
and suspends syncer, while waiting for variable reset for resume.  It
is used for debugging; should be removed after the real use of the
interface is added.

In collaboration with:	pho
Discussed with:	avg
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2014-12-13 16:18:29 +00:00
Mateusz Guzik
eb48fbd963 filedesc: fixup fdinit to lock fdp and preapare files conditinally
Not all consumers providing fdp to copy from want files.

Perhaps these functions should be reorganized to better express the outcome.

This fixes up panics after r273895 .

Reported by:	markj
2014-11-13 21:15:09 +00:00
Mateusz Guzik
b9d32c36fa Make fdunshare accept only td parameter.
Proc had to match the thread anyway and 2 parameters were inconsistent
with the rest.

MFC after:	1 week
2014-06-28 05:41:53 +00:00
Mark Johnston
7159310fa6 The fasttrap fork handler is responsible for removing tracepoints in the
child process that were inherited from its parent. However, this should
not be done in the case of a vfork, since the fork handler ends up removing
the tracepoints from the shared vm space, and userland DTrace probes in the
parent will no longer fire as a result.

Now the child of a vfork may trigger userland DTrace probes enabled in its
parent, so modify the fasttrap probe handler to handle this case and handle
the child process in the same way that it would handle the traced process.
In particular, if once traces function foo() in a process that vforks, and
the child calls foo(), fasttrap will treat this call as having come from the
parent. This is the behaviour of the upstream code.

While here, add #ifdef guards to some code that isn't present upstream.

MFC after:	1 month
2013-12-18 01:41:52 +00:00
Pawel Jakub Dawidek
f2b525e6b9 Make process descriptors standard part of the kernel. rwhod(8) already
requires process descriptors to work and having PROCDESC in GENERIC
seems not enough, especially that we hope to have more and more consumers
in the base.

MFC after:	3 days
2013-11-30 15:08:35 +00:00
Andriy Gapon
d9fae5ab88 dtrace sdt: remove the ugly sname parameter of SDT_PROBE_DEFINE
In its stead use the Solaris / illumos approach of emulating '-' (dash)
in probe names with '__' (two consecutive underscores).

Reviewed by:	markj
MFC after:	3 weeks
2013-11-26 08:46:27 +00:00
Attilio Rao
54366c0bd7 - For kernel compiled only with KDTRACE_HOOKS and not any lock debugging
option, unbreak the lock tracing release semantic by embedding
  calls to LOCKSTAT_PROFILE_RELEASE_LOCK() direclty in the inlined
  version of the releasing functions for mutex, rwlock and sxlock.
  Failing to do so skips the lockstat_probe_func invokation for
  unlocking.
- As part of the LOCKSTAT support is inlined in mutex operation, for
  kernel compiled without lock debugging options, potentially every
  consumer must be compiled including opt_kdtrace.h.
  Fix this by moving KDTRACE_HOOKS into opt_global.h and remove the
  dependency by opt_kdtrace.h for all files, as now only KDTRACE_FRAMES
  is linked there and it is only used as a compile-time stub [0].

[0] immediately shows some new bug as DTRACE-derived support for debug
in sfxge is broken and it was never really tested.  As it was not
including correctly opt_kdtrace.h before it was never enabled so it
was kept broken for a while.  Fix this by using a protection stub,
leaving sfxge driver authors the responsibility for fixing it
appropriately [1].

Sponsored by:	EMC / Isilon storage division
Discussed with:	rstone
[0] Reported by:	rstone
[1] Discussed with:	philip
2013-11-25 07:38:45 +00:00
John Baldwin
55648840de Extend the support for exempting processes from being killed when swap is
exhausted.
- Add a new protect(1) command that can be used to set or revoke protection
  from arbitrary processes.  Similar to ktrace it can apply a change to all
  existing descendants of a process as well as future descendants.
- Add a new procctl(2) system call that provides a generic interface for
  control operations on processes (as opposed to the debugger-specific
  operations provided by ptrace(2)).  procctl(2) uses a combination of
  idtype_t and an id to identify the set of processes on which to operate
  similar to wait6().
- Add a PROC_SPROTECT control operation to manage the protection status
  of a set of processes.  MADV_PROTECT still works for backwards
  compatability.
- Add a p_flag2 to struct proc (and a corresponding ki_flag2 to kinfo_proc)
  the first bit of which is used to track if P_PROTECT should be inherited
  by new child processes.

Reviewed by:	kib, jilles (earlier version)
Approved by:	re (delphij)
MFC after:	1 month
2013-09-19 18:53:42 +00:00
Mark Johnston
7b77e1fe0f Specify SDT probe argument types in the probe definition itself rather than
using SDT_PROBE_ARGTYPE(). This will make it easy to extend the SDT(9) API
to allow probes with dynamically-translated types.

There is no functional change.

MFC after:	2 weeks
2013-08-15 04:08:55 +00:00
Jaakko Heinonen
a208417c41 Include PID in the error message which is printed when the maxproc limit
is exceeded. Improve formatting of the message while here.

PR:		kern/60550
Submitted by:	Lowell Gilbert, bde
2013-04-19 15:19:29 +00:00