Commit Graph

237 Commits

Author SHA1 Message Date
Mark Johnston
fee2a2fa39 Change synchonization rules for vm_page reference counting.
There are several mechanisms by which a vm_page reference is held,
preventing the page from being freed back to the page allocator.  In
particular, holding the page's object lock is sufficient to prevent the
page from being freed; holding the busy lock or a wiring is sufficent as
well.  These references are protected by the page lock, which must
therefore be acquired for many per-page operations.  This results in
false sharing since the page locks are external to the vm_page
structures themselves and each lock protects multiple structures.

Transition to using an atomically updated per-page reference counter.
The object's reference is counted using a flag bit in the counter.  A
second flag bit is used to atomically block new references via
pmap_extract_and_hold() while removing managed mappings of a page.
Thus, the reference count of a page is guaranteed not to increase if the
page is unbusied, unmapped, and the object's write lock is held.  As
a consequence of this, the page lock no longer protects a page's
identity; operations which move pages between objects are now
synchronized solely by the objects' locks.

The vm_page_wire() and vm_page_unwire() KPIs are changed.  The former
requires that either the object lock or the busy lock is held.  The
latter no longer has a return value and may free the page if it releases
the last reference to that page.  vm_page_unwire_noq() behaves the same
as before; the caller is responsible for checking its return value and
freeing or enqueuing the page as appropriate.  vm_page_wire_mapped() is
introduced for use in pmap_extract_and_hold().  It fails if the page is
concurrently being unmapped, typically triggering a fallback to the
fault handler.  vm_page_wire() no longer requires the page lock and
vm_page_unwire() now internally acquires the page lock when releasing
the last wiring of a page (since the page lock still protects a page's
queue state).  In particular, synchronization details are no longer
leaked into the caller.

The change excises the page lock from several frequently executed code
paths.  In particular, vm_object_terminate() no longer bounces between
page locks as it releases an object's pages, and direct I/O and
sendfile(SF_NOCACHE) completions no longer require the page lock.  In
these latter cases we now get linear scalability in the common scenario
where different threads are operating on different files.

__FreeBSD_version is bumped.  The DRM ports have been updated to
accomodate the KPI changes.

Reviewed by:	jeff (earlier version)
Tested by:	gallatin (earlier version), pho
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D20486
2019-09-09 21:32:42 +00:00
Mariusz Zaborski
9f5103abab process: style
We don't need to check if the parent is already set.
This is done already in the proc_reparent.

No functional behaviour changes intended.

MFC after:	1 month
2019-08-05 20:26:01 +00:00
Mark Johnston
918988576c Avoid relying on header pollution from sys/refcount.h.
MFC after:	3 days
Sponsored by:	The FreeBSD Foundation
2019-07-29 20:26:01 +00:00
John Baldwin
32451fb9fc Add ptrace op PT_GET_SC_RET.
This ptrace operation returns a structure containing the error and
return values from the current system call.  It is only valid when a
thread is stopped during a system call exit (PL_FLAG_SCX is set).

The sr_error member holds the error value from the system call.  Note
that this error value is the native FreeBSD error value that has _not_
been translated to an ABI-specific error value similar to the values
logged to ktrace.

If sr_error is zero, then the return values of the system call will be
set in sr_retval[0] and sr_retval[1].

Reviewed by:	kib
MFC after:	1 month
Sponsored by:	DARPA
Differential Revision:	https://reviews.freebsd.org/D20901
2019-07-15 21:48:02 +00:00
Mark Johnston
eeacb3b02f Merge the vm_page hold and wire mechanisms.
The hold_count and wire_count fields of struct vm_page are separate
reference counters with similar semantics.  The remaining essential
differences are that holds are not counted as a reference with respect
to LRU, and holds have an implicit free-on-last unhold semantic whereas
vm_page_unwire() callers must explicitly determine whether to free the
page once the last reference to the page is released.

This change removes the KPIs which directly manipulate hold_count.
Functions such as vm_fault_quick_hold_pages() now return wired pages
instead.  Since r328977 the overhead of maintaining LRU for wired pages
is lower, and in many cases vm_fault_quick_hold_pages() callers would
swap holds for wirings on the returned pages anyway, so with this change
we remove a number of page lock acquisitions.

No functional change is intended.  __FreeBSD_version is bumped.

Reviewed by:	alc, kib
Discussed with:	jeff
Discussed with:	jhb, np (cxgbe)
Tested by:	pho (previous version)
Sponsored by:	Netflix
Differential Revision:	https://reviews.freebsd.org/D19247
2019-07-08 19:46:20 +00:00
Conrad Meyer
daec92844e Include ktr.h in more compilation units
Similar to r348026, exhaustive search for uses of CTRn() and cross reference
ktr.h includes.  Where it was obvious that an OS compat header of some kind
included ktr.h indirectly, .c files were left alone.  Some of these files
clearly got ktr.h via header pollution in some scenarios, or tinderbox would
not be passing prior to this revision, but go ahead and explicitly include it
in files using it anyway.

Like r348026, these CUs did not show up in tinderbox as missing the include.

Reported by:	peterj (arm64/mp_machdep.c)
X-MFC-With:	r347984
Sponsored by:	Dell EMC Isilon
2019-05-21 20:38:48 +00:00
Mark Johnston
02164d3603 Add a missing definition for the !COMPAT_FREEBSD32 case.
Reported by:	jenkins
MFC with:	r341442
Sponsored by:	The FreeBSD Foundation
2018-12-03 21:07:10 +00:00
Mark Johnston
352aaa5122 Plug memory disclosures via ptrace(2).
On some architectures, the structures returned by PT_GET*REGS were not
fully populated and could contain uninitialized stack memory.  The same
issue existed with the register files in procfs.

Reported by:	Thomas Barabosch, Fraunhofer FKIE
Reviewed by:	kib
MFC after:	3 days
Security:	kernel stack memory disclosure
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D18421
2018-12-03 20:54:17 +00:00
Mateusz Guzik
2c054ce924 proc: always store parent pid in p_oppid
Doing so removes the dependency on proctree lock from sysctl process list
export which further reduces contention during poudriere -j 128 runs.

Reviewed by:	kib (previous version)
Sponsored by:	The FreeBSD Foundation
Differential Revision:	https://reviews.freebsd.org/D17825
2018-11-16 17:07:54 +00:00
Mark Johnston
2203c46d87 Initialize the eflags field of vm_map headers.
Initializing the eflags field of the map->header entry to a value with a
unique new bit set makes a few comparisons to &map->header unnecessary.

Submitted by:	Doug Moore <dougm@rice.edu>
Reviewed by:	alc, kib
Tested by:	pho
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D14005
2018-11-02 16:26:44 +00:00
Konstantin Belousov
a70e9a1388 Swap in WKILLED processes.
Swapped-out process that is WKILLED must be swapped in as soon as
possible.  The reason is that such process can be killed by OOM and
its pages can be only freed if the process exits.  To exit, the kernel
stack of the process must be mapped.

When allocating pages for the stack of the WKILLED process on swap in,
use VM_ALLOC_SYSTEM requests to increase the chance of the allocation
to succeed.

Add counter of the swapped out processes to avoid unneeded iteration
over the allprocs list when there is no work to do, reducing the
allproc_lock ownership.

Reviewed by:	alc, markj (previous version)
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Differential revision:	https://reviews.freebsd.org/D16489
2018-08-04 20:45:43 +00:00
Konstantin Belousov
ac4bc0c171 Update proc->p_ptevents annotation to reflect the actual locking.
Submitted by:	Yanko Yankulov <yanko.yankulov@gmail.com>
Reviewed by:	jhb
MFC after:	1 week
Differential revision:	https://reviews.freebsd.org/D15954
2018-06-21 21:07:25 +00:00
Matt Macy
ac8b2d5cb1 sys_process.c fix set but not used warning 2018-05-19 03:48:35 +00:00
Brooks Davis
6469bdcdb6 Move most of the contents of opt_compat.h to opt_global.h.
opt_compat.h is mentioned in nearly 180 files. In-progress network
driver compabibility improvements may add over 100 more so this is
closer to "just about everywhere" than "only some files" per the
guidance in sys/conf/options.

Keep COMPAT_LINUX32 in opt_compat.h as it is confined to a subset of
sys/compat/linux/*.c.  A fake _COMPAT_LINUX option ensure opt_compat.h
is created on all architectures.

Move COMPAT_LINUXKPI to opt_dontuse.h as it is only used to control the
set of compiled files.

Reviewed by:	kib, cem, jhb, jtl
Sponsored by:	DARPA, AFRL
Differential Revision:	https://reviews.freebsd.org/D14941
2018-04-06 17:35:35 +00:00
Pedro F. Giffuni
8a36da99de sys/kern: adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
2017-11-27 15:20:12 +00:00
John Baldwin
7e3e36068b Move loop to clear TDB_SUSPEND into PT_DETACH case.
The PT_DETACH case above the sendsig: label already looped over all
threads clearing flags in td_dbgflags.  Reuse this loop to clear
TDB_SUSPEND and move the logic out of the sendsig: block.
2017-11-13 21:22:33 +00:00
John Baldwin
2a2b23cae2 Pull the PT_ATTACH case out of the 'sendsig:' block.
Most of the conditionals in the 'sendsig:' block are now only different
for PT_ATTACH vs other continue requests.  Pull the PT_ATTACH-specific
logic up into the PT_ATTACH case and simplify the 'sendsig:' block.  This
also permits moving the unlock of proctree_lock above the sendsig: label
since PT_KILL doesn't hold the lock and and the other cases all fall
through to the label.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D13073
2017-11-13 21:09:08 +00:00
John Baldwin
feeaec18d4 Only clear a pending thread event if one is pending.
This fixes a panic when attaching to an already-stopped process after
r325028.  While here, clean up a few other things in the control flow
of the 'sendsig' section:
- Only check for P_STOPPED_TRACE rather than either of P_STOPPED_SIG
  or P_STOPPED_TRACE for most ptrace requests.  The signal handling
  code in kern_sig.c never sets just P_STOPPED_SIG for a traced
  process, so if P_STOPPED_SIG is stopped, P_STOPPED_TRACE should be
  set anyway.  Remove a related debug printf.  Assuming P_STOPPED_TRACE
  permits simplifications in the 'sendsig:' block.
- Move the block to clear the pending thread state up into a new
  block conditional on P_STOPPED_TRACE and handle delivering pending
  signals to the reporting thread and clearing the reporting thread's
  state in this block.
- Consolidate case to send a signal to the process in a single case
  for PT_ATTACH.  The only case that could have been in the else before
  was a PT_ATTACH where P_STOPPED_SIG was not set, so both instances
  of kern_psignal() collapse down to just PT_ATTACH.

Reported by:	pho, mmel
Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D12837
2017-11-13 19:58:58 +00:00
Konstantin Belousov
9acf7b136d Zero whole struct ptrace_lwpinfo to not leak kernel stack data.
Reported by:	Ilja Van Sprundel <ivansprundel@ioactive.com>
Discussed with:	secteam
Reviewed by:	jhb
Sponsored by:	The FreeBSD Foundation
MFC after:	3 days
Differential revision:	https://reviews.freebsd.org/D12796
2017-11-08 23:32:56 +00:00
John Baldwin
e012fe34cb Discard the correct thread event reported for a ptrace stop.
When multiple threads wish to report a tracing event to a debugger,
both threads call ptracestop() and one thread will win the race to be
the reporting thread (p->p_xthread).  The debugger uses PT_LWPINFO
with the process ID to determine which thread / LWP is reporting an
event and the details of that event.  This event is cleared as a side
effect of the subsequent ptrace event that resumed the process
(PT_CONTINUE, PT_STEP, etc.).  However, ptrace() was clearing the
event identified by the LWP ID passed to the resume request even if
that wasn't the 'p_xthread'.  This could result in clearing an event
that had not yet been observed by the debugger and leaving the
existing event for 'p_thread' pending so that it was reported a second
time.

Specifically, if the debugger stopped due to a software breakpoint in
one thread, but then switched to another thread that was used to
resume (e.g. if the user switched to a different thread and issued a
step), the resume request (PT_STEP) cleared a pending event (if any)
for the thread being stepped.  However, the process immediately
stopped and the first thread reported it's breakpoint event a second
time.  The debugger decremented the PC for "both" breakpoint events
which resulted in the PC now pointing into the middle of an
instruction (on x86) and a SIGILL fault when the process was resumed a
second time.

To fix, always clear the pending event for 'p_xthread' when resuming a
process.  ptrace() still honors the requested LWP ID when enabling
single-stepping (PT_STEP) or setting a different PC (PT_CONTINUE).

Reported by:	GDB testsuite (gdb.threads/continue-pending-status.exp)
Reviewed by:	kib
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D12794
2017-10-27 03:16:19 +00:00
John Baldwin
09f3bb8756 Log signal number passed to PT_STEP requests in KTR_PTRACE traces.
MFC after:	1 week
2017-09-25 20:38:55 +00:00
John Baldwin
51645e836d Store a 32-bit PT_LWPINFO struct for 32-bit process core dumps.
Process core notes for a 32-bit process running on a 64-bit host need to
use 32-bit structures so that the note layout matches the layout of notes
of a core dump of a 32-bit process under a 32-bit kernel.

Reviewed by:	kib
Differential Revision:	https://reviews.freebsd.org/D11407
2017-06-29 21:31:13 +00:00
Konstantin Belousov
b43ce76c77 Add ptrace(PT_GET_SC_ARGS) command to return debuggee' current syscall
arguments.

Reviewed by:	jhb (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	3 weeks
Differential revision:	https://reviews.freebsd.org/D11080
2017-06-12 21:15:43 +00:00
Konstantin Belousov
2d88da2f06 Move struct syscall_args syscall arguments parameters container into
struct thread.

For all architectures, the syscall trap handlers have to allocate the
structure on the stack.  The structure takes 88 bytes on 64bit arches
which is not negligible.  Also, it cannot be easily found by other
code, which e.g. caused duplication of some members of the structure
to struct thread already.  The change removes td_dbg_sc_code and
td_dbg_sc_nargs which were directly copied from syscall_args.

The structure is put into the copied on fork part of the struct thread
to make the syscall arguments information correct in the child after
fork.

This move will also allow several more uses shortly.

Reviewed by:	jhb (previous version)
Sponsored by:	The FreeBSD Foundation
MFC after:	3 weeks
X-Differential revision:	https://reviews.freebsd.org/D11080
2017-06-12 21:03:23 +00:00
Tycho Nightingale
86be94fca3 Add support for capturing 'struct ptrace_lwpinfo' for signals
resulting in a process dumping core in the corefile.

Also extend procstat to view select members of 'struct ptrace_lwpinfo'
from the contents of the note.

Sponsored by:	Dell EMC Isilon
2017-03-30 18:21:36 +00:00
Eric Badger
82a4538f31 Defer ptracestop() signals that cannot be delivered immediately
When a thread is stopped in ptracestop(), the ptrace(2) user may request
a signal be delivered upon resumption of the thread. Heretofore, those signals
were discarded unless ptracestop()'s caller was issignal(). Fix this by
modifying ptracestop() to queue up signals requested by the ptrace user that
will be delivered when possible. Take special care when the signal is SIGKILL
(usually generated from a PT_KILL request); no new stop events should be
triggered after a PT_KILL.

Add a number of tests for the new functionality. Several tests were authored
by jhb.

PR:		212607
Reviewed by:	kib
Approved by:	kib (mentor)
MFC after:	2 weeks
Sponsored by:	Dell EMC
In collaboration with:	jhb
Differential Revision:	https://reviews.freebsd.org/D9260
2017-02-20 15:53:16 +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
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
Konstantin Belousov
f470cca578 In ptrace_vm_entry(), do not call vmspace_free() while owning a vm
object lock.

The vmspace_free() operations might need to lock map, object etc on
last dereference.  Postpone the free until object's inspection is
done.

Reported and tested by:	will
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2016-07-15 23:26:33 +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
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
711fbd17ec Add helper functions proc_readmem() and proc_writemem().
These helper functions can be used to read in or write a buffer from or to
an arbitrary process' address space. Without them, this can only be done
using proc_rwmem(), which requires the caller to fill out a uio. This is
onerous and results in code duplication; the new functions provide a simpler
interface which is sufficient for most existing callers of proc_rwmem().

This change also adds a manual page for proc_rwmem() and the new functions.

Reviewed by:	jhb, kib
Differential Revision:	https://reviews.freebsd.org/D4245
2015-12-07 21:33:15 +00:00
Mark Johnston
d28713378a - Consistently use PROC_ASSERT_HELD() to verify that a process' hold count
is non-zero.
- Include the process address in the PROC_ASSERT_HELD() and
  PROC_ASSERT_NOT_HELD() assertion messages so that the corresponding
  process can be found easily when debugging.

MFC after:	1 week
2015-11-08 01:38:56 +00:00
Konstantin Belousov
8fc3db038e Trim spaces at end of line to record the proper commit message for
r289660:

Do not allow to execute ptrace(PT_TRACE_ME) when the process is
already traced.

Do not allow to execute ptrace(PT_TRACE_ME) when there is no parent
which can trace the process, i.e. when the parent is already init.
Note that after the PT_TRACE_ME request the process is unkillable and
non-continuable until a debugger is attached, or parent is killed, the
later clears P_TRACED state.  Since init clearly would not debug the
caller, and cannot be killed, disallow creation of unkillable
processes.

Reviewed by:	jhb, pho
Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Differential revision:	https://reviews.freebsd.org/D3908
2015-10-20 20:38:20 +00:00
Konstantin Belousov
77b9bec37b Reviewed by: jhb, pho
Reported and tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
Differential revision:	https://reviews.freebsd.org/D3908
2015-10-20 20:22:57 +00:00
Konstantin Belousov
1ed2e49b55 No need to dereference struct proc to pids when comparing processes
for equality.

Reviewed by:	jhb, pho
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2015-10-20 20:12:42 +00:00
John Baldwin
c814b86843 Switch pl_child_pid from int to pid_t.
Reviewed by:	emaste, kib
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D3857
2015-10-20 17:58:21 +00:00
John Baldwin
3edd0ffffe Include additional info in ptrace(2) KTR traces:
- The new PC value and signal passed to PT_CONTINUE, PT_DETACH, PT_SYSCALL,
  and PT_TO_SC[EX].
- The system call code returned via PT_LWPINFO.

MFC after:	1 week
2015-10-05 21:36:53 +00:00
John Baldwin
183b68f74f Export current system call code and argument count for system call entry
and exit events. procfs stop events for system call tracing report these
values (argument count for system call entry and code for system call exit),
but ptrace() does not provide this information. (Note that while the system
call code can be determined in an ABI-specific manner during system call
entry, it is not generally available during system call exit.)

The values are exported via new fields at the end of struct ptrace_lwpinfo
available via PT_LWPINFO.

Reviewed by:	kib
MFC after:	1 week
Differential Revision:	https://reviews.freebsd.org/D3536
2015-09-01 22:24:54 +00:00
John Baldwin
98685dc8af Clear P_TRACED before reparenting a detached process back to its
original parent. Otherwise the debugee will be set as an orphan of
the debugger.

Add tests for tracing forks via PT_FOLLOW_FORK.

Reviewed by:	kib
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D2809
2015-08-01 16:27:52 +00:00
Konstantin Belousov
b4490c6e93 The si_status field of the siginfo_t, provided by the waitid(2) and
SIGCHLD signal, should keep full 32 bits of the status passed to the
_exit(2).

Split the combined p_xstat of the struct proc into the separate exit
status p_xexit for normal process exit, and signalled termination
information p_xsig.  Kernel-visible macro KW_EXITCODE() reconstructs
old p_xstat from p_xexit and p_xsig.  p_xexit contains complete status
and copied out into si_status.

Requested by:	Joerg Schilling
Reviewed by:	jilles (previous version), pho
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
2015-07-18 09:02:50 +00:00
Eric van Gyzen
63e4c6cdf9 Provide vnode in memory map info for files on tmpfs
When providing memory map information to userland, populate the vnode pointer
for tmpfs files.  Set the memory mapping to appear as a vnode type, to match
FreeBSD 9 behavior.

This fixes the use of tmpfs files with the dtrace pid provider,
procstat -v, procfs, linprocfs, pmc (pmcstat), and ptrace (PT_VM_ENTRY).

Submitted by:   Eric Badger <eric@badgerio.us> (initial revision)
Obtained from:  Dell Inc.
PR:             198431
MFC after:      2 weeks
Reviewed by:    jhb
Approved by:    kib (mentor)
2015-06-02 18:37:04 +00:00
Xin LI
4c372ca254 Clear p_stops when doing PT_DETACH.
Without this, if a process was being traced by truss(1), which
uses different p_stops bits than gdb(1), the latter would
misbehave because of the unexpected bits.

Reported by:	jceel
Submitted by:	sef
Sponsored by:	iXsystems, Inc.
MFC after:	2 weeks
2015-06-01 18:15:45 +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
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
Mateusz Guzik
4bc68ed7bc Plug unnecessary PRS_NEW check in kern_procctl.
pfind does not return processes in such state.
2014-10-22 04:16:09 +00:00
John Baldwin
7aa1071e48 Require p_cansched() for changing a process' protection status via
procctl() rather than p_cansee().

Submitted by:	rwatson
MFC after:	3 days
2014-10-02 21:18:16 +00:00
Konstantin Belousov
d735998057 Correct the problems with the ptrace(2) making the debuggee an orphan.
One problem is inferior(9) looping due to the process tree becoming a
graph instead of tree if the parent is traced by child. Another issue
is due to the use of p_oppid to restore the original parent/child
relationship, because real parent could already exited and its pid
reused (noted by mjg).

Add the function proc_realparent(9), which calculates the parent for
given process. It uses the flag P_TREE_FIRST_ORPHAN to detect the head
element of the p_orphan list and than stepping back to its container
to find the parent process. If the parent has already exited, the
init(8) is returned.

Move the P_ORPHAN and the new helper flag from the p_flag* to new
p_treeflag field of struct proc, which is protected by proctree lock
instead of proc lock, since the orphans relationship is managed under
the proctree_lock already.

The remaining uses of p_oppid in ptrace(PT_DETACH) and process
reapping are replaced by proc_realparent(9).

Phabric:	D417
Reviewed by:	jhb
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2014-08-07 05:47:53 +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