Commit Graph

348 Commits

Author SHA1 Message Date
Mateusz Guzik
e94e50af1d racct: perform a lockless check for p_throttled
This reduces proc lock contention.

Reviewed by:	trasz
2015-07-13 22:52:11 +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
Konstantin Belousov
1bc93bb7b9 Currently, softupdate code detects overstepping on the workitems
limits in the code which is deep in the call stack, and owns several
critical system resources, like vnode locks.  Attempt to wait while
the per-mount softupdate thread cleans up the backlog may deadlock,
because the thread might need to lock the same vnode which is owned by
the waiting thread.

Instead of synchronously waiting for the worker, perform the worker'
tickle and pause until the backlog is cleaned, at the safe point
during return from kernel to usermode.  A new ast request to call
softdep_ast_cleanup() is created, the SU code now only checks the size
of queue and schedules ast.

There is no ast delivery for the kernel threads, so they are exempted
from the mechanism, except NFS daemon threads.  NFS server loop
explicitely checks for the request, and informs the schedule_cleanup()
that it is capable of handling the requests by the process P2_AST_SU
flag.  This is needed because nfsd may be the sole cause of the SU
workqueue overflow.  But, to not cause nsfd to spawn additional
threads just because we slow down existing workers, only tickle su
threads, without waiting for the backlog cleanup.

Reviewed by:	jhb, mckusick
Tested by:	pho
Sponsored by:	The FreeBSD Foundation
MFC after:	2 weeks
2015-05-27 09:20:42 +00:00
John Baldwin
ed95805e90 Remove support for Xen PV domU kernels. Support for HVM domU kernels
remains.  Xen is planning to phase out support for PV upstream since it
is harder to maintain and has more overhead.  Modern x86 CPUs include
virtualization extensions that support HVM guests instead of PV guests.
In addition, the PV code was i386 only and not as well maintained recently
as the HVM code.
- Remove the i386-only NATIVE option that was used to disable certain
  components for PV kernels.  These components are now standard as they
  are on amd64.
- Remove !XENHVM bits from PV drivers.
- Remove various shims required for XEN (e.g. PT_UPDATES_FLUSH, LOAD_CR3,
  etc.)
- Remove duplicate copy of <xen/features.h>.
- Remove unused, i386-only xenstored.h.

Differential Revision:	https://reviews.freebsd.org/D2362
Reviewed by:	royger
Tested by:	royger (i386/amd64 HVM domU and amd64 PVH dom0)
Relnotes:	yes
2015-04-30 15:48:48 +00:00
Edward Tomasz Napierala
4b5c9cf62f Add kern.racct.enable tunable and RACCT_DISABLED config option.
The point of this is to be able to add RACCT (with RACCT_DISABLED)
to GENERIC, to avoid having to rebuild the kernel to use rctl(8).

Differential Revision:	https://reviews.freebsd.org/D2369
Reviewed by:	kib@
MFC after:	1 month
Relnotes:	yes
Sponsored by:	The FreeBSD Foundation
2015-04-29 10:23:02 +00:00
Konstantin Belousov
18cc2ff047 Revert r263475: TDP_DEVMEMIO no longer needed, since amd64 /dev/kmem
does not access kernel mappings directly.

Reviewed by:	alc
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2015-01-12 08:58:07 +00:00
Konstantin Belousov
52f3c44efe Fix two issues with /dev/mem access on amd64, both causing kernel page
faults.

First, for accesses to direct map region should check for the limit by
which direct map is instantiated.

Second, for accesses to the kernel map, success returned from the
kernacc(9) does not guarantee that consequent attempt to read or write
to the checked address succeed, since other thread might invalidate
the address meantime.  Add a new thread private flag TDP_DEVMEMIO,
which instructs vm_fault() to return error when fault happens on the
MAP_ENTRY_NOFAULT entry, instead of panicing.  The trap handler would
then see a page fault from access, and recover in normal way, making
/dev/mem access safer.

Remove GIANT_REQUIRED from the amd64 memrw(), since it is not needed
and having Giant locked does not solve issues for amd64.

Note that at least the second issue exists on other architectures, and
requires similar patching for md code.

Reported and tested by:	clusteradm (gjb, sbruno)
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
2014-03-21 14:25:09 +00:00
Robert Watson
4a14441044 Update kernel inclusions of capability.h to use capsicum.h instead; some
further refinement is required as some device drivers intended to be
portable over FreeBSD versions rely on __FreeBSD_version to decide whether
to include capability.h.

MFC after:	3 weeks
2014-03-16 10:55:57 +00:00
Attilio Rao
e7a9eed7a8 - Assert for not leaking readers rw locks counter on userland return.
- Use a correct spin_cnt for KDTRACE_HOOK case in rw read lock.

Sponsored by:	EMC / Isilon storage division
2013-12-17 13:37:02 +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
3cf3b9f097 Partially revert r195702. Deferring stops is now implemented via a set of
calls to toggle TDF_SBDRY rather than passing PBDRY to individual sleep
calls.
- Remove the stop_allowed parameters from cursig() and issignal().
  issignal() checks TDF_SBDRY directly.
- Remove the PBDRY and SLEEPQ_STOP_ON_BDRY flags.
2013-03-18 17:23:58 +00:00
Edward Tomasz Napierala
a8efb53478 When throttling a process to enforce RACCT limits, do not use neither
PBDRY (which simply doesn't make any sense) nor PCATCH (which could
be used by a malicious process to work around the PCPU limit).

Submitted by:	Rudo Tomori
Reviewed by:	kib
2013-03-14 23:25:42 +00:00
John Baldwin
f9379dc411 Replace the TDP_NOSLEEPING flag with a counter so that the
THREAD_NO_SLEEPING() and THREAD_SLEEPING_OK() macros can nest.

Reviewed by:	attilio
2013-03-01 22:03:31 +00:00
John Baldwin
593efaf9f7 Further refine the handling of stop signals in the NFS client. The
changes in r246417 were incomplete as they did not add explicit calls to
sigdeferstop() around all the places that previously passed SBDRY to
_sleep().  In addition, nfs_getcacheblk() could trigger a write RPC from
getblk() resulting in sigdeferstop() recursing.  Rather than manually
deferring stop signals in specific places, change the VFS_*() and VOP_*()
methods to defer stop signals for filesystems which request this behavior
via a new VFCF_SBDRY flag.  Note that this has to be a VFC flag rather than
a MNTK flag so that it works properly with VFS_MOUNT() when the mount is
not yet fully constructed.  For now, only the NFS clients are set this new
flag in VFS_SET().

A few other related changes:
- Add an assertion to ensure that TDF_SBDRY doesn't leak to userland.
- When a lookup request uses VOP_READLINK() to follow a symlink, mark
  the request as being on behalf of the thread performing the lookup
  (cnp_thread) rather than using a NULL thread pointer.  This causes
  NFS to properly handle signals during this VOP on an interruptible
  mount.

PR:		kern/176179
Reported by:	Russell Cattelan (sigdeferstop() recursion)
Reviewed by:	kib
MFC after:	1 month
2013-02-21 19:02:50 +00:00
Attilio Rao
5584e91718 Fixup r240246: hwpmc needs to retain the pinning until ASTs are not
executed. This means past the point where userret() is generally
executed.

Skip the td_pinned check if a callchain tracing is currently happening
and add a more robust check to pmc_capture_user_callchain() in order to
catch td_pinned leak past ast() in hwpmc case.

Reported and tested by:	fabient
MFC after:	1 week
X-MFC:	r240246
2012-10-30 15:10:50 +00:00
Edward Tomasz Napierala
36af98697d Add CPU percentage limit enforcement to RCTL. The resouce name is "pcpu".
It was implemented by Rudolf Tomori during Google Summer of Code 2012.
2012-10-26 16:01:08 +00:00
Konstantin Belousov
9b233e2307 Add a KPI to allow to reserve some amount of space in the numvnodes
counter, without actually allocating the vnodes. The supposed use of
the getnewvnode_reserve(9) is to reclaim enough free vnodes while the
code still does not hold any resources that might be needed during the
reclamation, and to consume the slack later for getnewvnode() calls
made from the innards. After the critical block is finished, the
caller shall free any reserve left, by getnewvnode_drop_reserve(9).

Reviewed by:	avg
Tested by:	pho
MFC after:	1 week
2012-10-14 19:43:37 +00:00
Attilio Rao
16cbf13b53 Move the checks for td_pinned, td_critnest, TDP_NOFAULTING and
TDP_NOSLEEPING leaking from syscallret() to userret() so that also
trap handling is covered. Also, the check on td_locks is not duplicated
between the two functions.

Reported by:	avg
Reviewed by:	kib
MFC after:	1 week
2012-09-08 18:35:15 +00:00
Attilio Rao
fbe18392a1 Move PT_UPDATED_FLUSH() before td_locks check in order to have more
coverage also in the XEN case.

Reviewed by:	kib
MFC after:	1 week
2012-09-08 18:29:53 +00:00
Attilio Rao
324e57150d userret() already checks for td_locks when INVARIANTS is enabled, so
there is no need to check if Giant is acquired after it.

Reviewed by:	kib
MFC after:	1 week
2012-09-08 18:27:11 +00:00
Pawel Jakub Dawidek
effb6326a1 Remove redundant include.
MFC after:	1 month
2012-06-10 20:24:01 +00:00
John Baldwin
88bf5036fc Include the associated wait channel message for context switch ktrace
records.  kdump supports both the old and new messages.

Submitted by:	Andrey Zonov  andrey zonov org
MFC after:	1 week
2012-04-20 15:32:36 +00:00
Fabien Thomas
f5f9340b98 Add software PMC support.
New kernel events can be added at various location for sampling or counting.
This will for example allow easy system profiling whatever the processor is
with known tools like pmcstat(8).

Simultaneous usage of software PMC and hardware PMC is possible, for example
looking at the lock acquire failure, page fault while sampling on
instructions.

Sponsored by: NETASQ
MFC after:	1 month
2012-03-28 20:58:30 +00:00
Konstantin Belousov
24f3dcfe50 Assert that exiting process does not return to usermode.
Reviewed by:	avg, jhb
MFC after:	1 week
2011-10-03 16:58:58 +00:00
Kip Macy
8451d0dd78 In order to maximize the re-usability of kernel code in user space this
patch modifies makesyscalls.sh to prefix all of the non-compatibility
calls (e.g. not linux_, freebsd32_) with sys_ and updates the kernel
entry points and all places in the code that use them. It also
fixes an additional name space collision between the kernel function
psignal and the libc function of the same name by renaming the kernel
psignal kern_psignal(). By introducing this change now we will ease future
MFCs that change syscalls.

Reviewed by:	rwatson
Approved by:	re (bz)
2011-09-16 13:58:51 +00:00
Konstantin Belousov
26ccf4f10f Inline the syscallenter() and syscallret(). This reduces the time measured
by the syscall entry speed microbenchmarks by ~10% on amd64.

Submitted by:	jhb
Approved by:	re (bz)
MFC after:	2 weeks
2011-09-11 16:05:09 +00:00
Jonathan Anderson
24c1c3bf71 We may split today's CAPABILITIES into CAPABILITY_MODE (which has
to do with global namespaces) and CAPABILITIES (which has to do with
constraining file descriptors). Just in case, and because it's a better
name anyway, let's move CAPABILITIES out of the way.

Also, change opt_capabilities.h to opt_capsicum.h; for now, this will
only hold CAPABILITY_MODE, but it will probably also hold the new
CAPABILITIES (implying constrained file descriptors) in the future.

Approved by: rwatson
Sponsored by: Google UK Ltd
2011-06-29 13:03:05 +00:00
Robert Watson
fc94e4476b Continue introducing Capsicum capability mode support:
If a system call wasn't listed in capabilities.conf, return ECAPMODE at
syscall entry.

Reviewed by:	anderson
Discussed with:	benl, kris, pjd
Sponsored by:	Google, Inc.
Obtained from:	Capsicum Project
MFC after:	3 months
2011-03-01 13:32:07 +00:00
Bjoern A. Zeeb
bf9ce95bd2 Mfp4 CH=177256:
Catch a set vnet upon return to user space. This usually
  means return paths with CURVNET_RESTORE() missing.

  If VNET_DEBUG is turned on we can even tell the function
  that did the CURVNET_SET() which is really helpful; else
  we print "N/A".

  Sponsored by: The FreeBSD Foundation
  Sponsored by: CK Software GmbH
  Reviewed by:  jhb

MFC after:	11 days
2011-02-14 20:49:37 +00:00
Konstantin Belousov
6fa39a7327 Allow debugger to specify that children of the traced process should be
automatically traced. Extend the ptrace(PL_LWPINFO) to report that child
just forked.

Reviewed by:	davidxu, jhb
MFC after:	2 weeks
2011-01-25 10:59:21 +00:00
Ed Maste
25e45560da Remove extra braces for style(9) (found while cleaning up an old work tree). 2010-09-28 01:36:01 +00:00
Rui Paulo
b3d354c9ce Call the systrace_probe_func() when the error value.
Sponsored by:	The FreeBSD Foundation
2010-08-22 11:30:49 +00:00
John Baldwin
f2a664ac97 Retire td_syscalls now that it is no longer needed. 2010-07-15 20:24:37 +00:00
Konstantin Belousov
34a39b7b1f Obey sv_syscallnames bounds in syscallname().
Reported and tested by:	pho
2010-07-04 18:16:17 +00:00
John Baldwin
fc0de8f0b6 Move prototypes for kern_sigtimedwait() and kern_sigprocmask() to
<sys/syscallsubr.h> where all other kern_<syscall> prototypes live.
2010-06-30 18:03:42 +00:00
Konstantin Belousov
153ac44cf6 Count number of threads that enter and leave dynamically registered
syscalls. On the dynamic syscall deregistration, wait until all
threads leave the syscall code. This somewhat increases the safety
of the loadable modules unloading.

Reviewed by:	jhb
Tested by:	pho
MFC after:	1 month
2010-06-28 18:06:46 +00:00
Konstantin Belousov
699d648aab Remove the support for int13 FPU exception reporting on i386. It is
believed that all 486-class CPUs FreeBSD is capable to run on, either
have no FPU and cannot use external coprocessor, or have FPU on the
package and can use #MF.

Reviewed by:	bde
Tested by:	pho (previous version)
2010-06-23 11:12:58 +00:00
Rui Paulo
f05a947676 Make DTrace syscall provider work again by including opt_kdtrace.h here. 2010-06-17 17:34:45 +00:00
Konstantin Belousov
b2318c2860 Allow to use syscallname(9) outside subr_trap.c.
MFC after:	1 month
2010-05-26 15:39:43 +00:00
Konstantin Belousov
afe1a68827 Reorganize syscall entry and leave handling.
Extend struct sysvec with three new elements:
sv_fetch_syscall_args - the method to fetch syscall arguments from
  usermode into struct syscall_args. The structure is machine-depended
  (this might be reconsidered after all architectures are converted).
sv_set_syscall_retval - the method to set a return value for usermode
  from the syscall. It is a generalization of
  cpu_set_syscall_retval(9) to allow ABIs to override the way to set a
  return value.
sv_syscallnames - the table of syscall names.

Use sv_set_syscall_retval in kern_sigsuspend() instead of hardcoding
the call to cpu_set_syscall_retval().

The new functions syscallenter(9) and syscallret(9) are provided that
use sv_*syscall* pointers and contain the common repeated code from
the syscall() implementations for the architecture-specific syscall
trap handlers.

Syscallenter() fetches arguments, calls syscall implementation from
ABI sysent table, and set up return frame. The end of syscall
bookkeeping is done by syscallret().

Take advantage of single place for MI syscall handling code and
implement ptrace_lwpinfo pl_flags PL_FLAG_SCE, PL_FLAG_SCX and
PL_FLAG_EXEC. The SCE and SCX flags notify the debugger that the
thread is stopped at syscall entry or return point respectively.  The
EXEC flag augments SCX and notifies debugger that the process address
space was changed by one of exec(2)-family syscalls.

The i386, amd64, sparc64, sun4v, powerpc and ia64 syscall()s are
changed to use syscallenter()/syscallret(). MIPS and arm are not
converted and use the mostly unchanged syscall() implementation.

Reviewed by:	jhb, marcel, marius, nwhitehorn, stas
Tested by:	marcel (ia64), marius (sparc64), nwhitehorn (powerpc),
	stas (mips)
MFC after:	1 month
2010-05-23 18:32:02 +00:00
Konstantin Belousov
066d836b02 Current pselect(3) is implemented in usermode and thus vulnerable to
well-known race condition, which elimination was the reason for the
function appearance in first place. If sigmask supplied as argument to
pselect() enables a signal, the signal might be delivered before thread
called select(2), causing lost wakeup. Reimplement pselect() in kernel,
making change of sigmask and sleep atomic.

Since signal shall be delivered to the usermode, but sigmask restored,
set TDP_OLDMASK and save old mask in td_oldsigmask. The TDP_OLDMASK
should be cleared by ast() in case signal was not gelivered during
syscall execution.

Reviewed by:	davidxu
Tested by:	pho
MFC after:	1 month
2009-10-27 10:55:34 +00:00
Konstantin Belousov
6b286ee8b5 Currently, when signal is delivered to the process and there is a thread
not blocking the signal, signal is placed on the thread sigqueue. If
the selected thread is in kernel executing thr_exit() or sigprocmask()
syscalls, then signal might be not delivered to usermode for arbitrary
amount of time, and for exiting thread it is lost.

Put process-directed signals to the process queue unconditionally,
selecting the thread to deliver the signal only by the thread returning
to usermode, since only then the thread can handle delivery of signal
reliably. For exiting thread or thread that has blocked some signals,
check whether the newly blocked signal is queued for the process, and
try to find a thread to wakeup for delivery, in reschedule_signal(). For
exiting thread, assume that all signals are blocked.

Change cursig() and postsig() to look both into the thread and process
signal queues. When there is a signal that thread returning to usermode
could consume, TDF_NEEDSIGCHK flag is not neccessary set now. Do
unlocked read of p_siglist and p_pendingcnt to check for queued signals.

Note that thread that has a signal unblocked might get spurious wakeup
and EINTR from the interruptible system call now, due to the possibility
of being selected by reschedule_signals(), while other thread returned
to usermode earlier and removed the signal from process queue. This
should not cause compliance issues, since the thread has not blocked a
signal and thus should be ready to receive it anyway.

Reported by:	Justin Teller <justin.teller gmail com>
Reviewed by:	davidxu, jilles
MFC after:	1 month
2009-10-11 16:49:30 +00:00
Konstantin Belousov
f33a947b56 Add new msleep(9) flag PBDY that shall be specified together with
PCATCH, to indicate that thread shall not be stopped upon receipt of
SIGSTOP until it reaches the kernel->usermode boundary.

Also change thread_single(SINGLE_NO_EXIT) to only stop threads at
the user boundary unconditionally.

Tested by:	pho
Reviewed by:	jhb
Approved by:	re (kensmith)
2009-07-14 22:52:46 +00:00
Robert Watson
bcf11e8d00 Move "options MAC" from opt_mac.h to opt_global.h, as it's now in GENERIC
and used in a large number of files, but also because an increasing number
of incorrect uses of MAC calls were sneaking in due to copy-and-paste of
MAC-aware code without the associated opt_mac.h include.

Discussed with:	pjd
2009-06-05 14:55:22 +00:00
Joseph Koshy
6fe00c7876 - Bug fix: prevent a thread from migrating between CPUs between the
time it is marked for user space callchain capture in the NMI
  handler and the time the callchain capture callback runs.

- Improve code and control flow clarity by invoking hwpmc(4)'s user
  space callchain capture callback directly from low-level code.

Reviewed by:	jhb (kern/subr_trap.c)
Testing (various patch revisions): gnn,
		Fabien Thomas <fabien dot thomas at netasq dot com>,
		Artem Belevich <artemb at gmail dot com>
2008-12-13 13:07:12 +00:00
Kip Macy
50d6e42434 - Forward port flush of page table updates on context switch or userret
- Forward port vfork XEN hack
2008-10-19 01:35:27 +00:00
Jeff Roberson
8df78c41d6 - Make SCHED_STATS more generic by adding a wrapper to create the
variables and sysctl nodes.
 - In reset walk the children of kern_sched_stats and reset the counters
   via the oid_arg1 pointer.  This allows us to add arbitrary counters to
   the tree and still reset them properly.
 - Define a set of switch types to be passed with flags to mi_switch().
   These types are named SWT_*.  These types correspond to SCHED_STATS
   counters and are automatically handled in this way.
 - Make the new SWT_ types more specific than the older switch stats.
   There are now stats for idle switches, remote idle wakeups, remote
   preemption ithreads idling, etc.
 - Add switch statistics for ULE's pickcpu algorithm.  These stats include
   how much migration there is, how often affinity was successful, how
   often threads were migrated to the local cpu on wakeup, etc.

Sponsored by:	Nokia
2008-04-17 04:20:10 +00:00
Jeff Roberson
b7edba7704 - Add a new td flag TDF_NEEDSUSPCHK that is set whenever a thread needs
to enter thread_suspend_check().
 - Set TDF_ASTPENDING along with TDF_NEEDSUSPCHK so we can move the
   thread_suspend_check() to ast() rather than userret().
 - Check TDF_NEEDSUSPCHK in the sleepq_catch_signals() optimization so
   that we don't miss a suspend request.  If this is set use the
   expensive signal path.
 - Set NEEDSUSPCHK when creating a new thread in thr in case the
   creating thread is due to be suspended as well but has not yet.

Reviewed by:	davidxu (Authored original patch)
2008-03-21 08:23:25 +00:00
Jeff Roberson
6617724c5f Remove kernel support for M:N threading.
While the KSE project was quite successful in bringing threading to
FreeBSD, the M:N approach taken by the kse library was never developed
to its full potential.  Backwards compatibility will be provided via
libmap.conf for dynamically linked binaries and static binaries will
be broken.
2008-03-12 10:12:01 +00:00
Joseph Koshy
d07f36b075 Kernel and hwpmc(4) support for callchain capture.
Sponsored by:	FreeBSD Foundation and Google Inc.
2007-12-07 08:20:17 +00:00