For anonymous objects, provide a handle kvo_me naming the object,
and report the handle of the backing object. This allows userspace
to deconstruct the shadow chain. Right now the handle is the address
of the object in KVA, but this is not guaranteed.
For the same anonymous objects, report the swap space used for actually
swapped out pages, in kvo_swapped field. I do not believe that it is
useful to report full 64bit counter there, so only uint32_t value is
returned, clamped to the max.
For kinfo_vmentry, report anonymous object handle backing the entry,
so that the shadow chain for the specific mapping can be deconstructed.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D29771
We were unlocking the vm object before reading the backing_object field.
In the meantime, the object could be freed and reused. This could cause
us to go off the rails in the object chain traversal, failing to unlock
the rest of the objects in the original chain and corrupting the lock
state of the victim chain.
Reviewed by: bdrewery, kib, markj, vangyzen
MFC after: 3 days
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D28926
kern.proc.proc_td returns the process table with an entry for each
thread. Previously the description included "no threads", presumably
a cut-and-pasteo in 2648efa621.
Description suggested by PauAmma.
PR: 253146
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Instead of trying to maintain pg_jobc counter on each process group
update (and sometimes before), just calculate the counter when needed.
Still, for the benefit of the signal delivery code, explicitly mark
orphaned groups as such with the new process group flag.
This way we prevent bugs in the corner cases where updates to the counter
were missed due to complicated configuration of p_pptr/p_opptr/real_parent
(debugger).
Since we need to iterate over all children of the process on exit, this
change mostly affects the process group entry and leave, where we need
to iterate all process group members to detect orpaned status.
(For MFC, keep pg_jobc around but unused).
Reported by: jhb
Reviewed by: jilles
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D27871
This improves code structure and allows to put the lock asserts right
into place where the locks are needed.
Also move zeroing of the kinfo_proc structure from fill_kinfo_proc_only()
to fill_kinfo_proc(), this looks more symmetrical.
Reviewed by: jilles
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D27871
Proctree lock is needed for correct calculation and collection of the
job-control related data in kinfo_proc. There was even an XXX comment
about it.
Satisfy locking and lock ordering requirements by taking proctree lock
around pass over each bucket in proc_iterate(), and in sysctl_kern_proc()
and note_procstat_proc() for individual process reporting.
Reviewed by: jilles
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D27871
Often, we have a process locked and need to get locked process group.
In this case, because progress group lock is before process lock,
unlocking process allows the group to be freed. See for instance
tty_wait_background().
Make pgrp structures allocated from nofree zone, and ensure type stability
of the pgrp mutex.
Reviewed by: jilles
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D27871
This is used by kernel debuggers to enumerate processes via the pid
hash table.
Reviewed by: kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D27825
No functional change intended.
Tracking these structures separately for each proc enables future work to
correctly emulate clone(2) in linux(4).
__FreeBSD_version is bumped (to 1300130) for consumption by, e.g., lsof.
Reviewed by: kib
Discussed with: markj, mjg
Differential Revision: https://reviews.freebsd.org/D27037
First, funsetownlst() list looks at the first element of the list to see
whether it's processing a process or a process group list. Then it
acquires the global sigio lock and processes the list. However, nothing
prevents the first sigio tracker from being freed by a concurrent
funsetown() before the sigio lock is acquired.
Fix this by acquiring the global sigio lock immediately after checking
whether the list is empty. Callers of funsetownlst() ensure that new
sigio trackers cannot be added concurrently.
Second, fsetown() uses funsetown() to remove an existing sigio structure
from a file object. However, funsetown() uses a racy check to avoid the
sigio lock, so two threads may call fsetown() on the same file object,
both observe that no sigio tracker is present, and enqueue two sigio
trackers for the same file object. However, if the file object is
destroyed, funsetown() will only remove one sigio tracker, and
funsetownlst() may later trigger a use-after-free when it clears the
file object reference for each entry in the list.
Fix this by introducing funsetown_locked(), which avoids the racy check.
Reviewed by: kib
Reported by: pho
Tested by: pho
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D27157
Both before and after job control adjustments.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D26416
Orphans affect job control state, we must account for them when
changing pg_jobc.
Instead of p_pptr, use proc_realparent() to get parent relevant for
job control.
Use correct calculation of the parent for exiting process. For jobc
purposes, we must use realparent, but if it is also exiting, we should
fall to reaper, then recursively find non-exiting reaper.
Reported by: trasz
PR: 249257
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D26416
Use ddb pager.
Make lines more compact.
Eliminate unneeded casts.
Print more job-control related info when reporting process group.
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D26416
Attempt of adding assertions that pgrp->pg_jobc counters do not
underflow in r361967, reverted in r362910, points out bugs in the
handling of job control. Peter Holm was able to narrow down the
problem to very easy reproduction with timeout(1) which uses reaping.
The following list of problems with calculation of pg_jobs which
directs SIGHUP/SIGCONT delivery for orphaned process group was
identified:
- Re-calculation of the orphaned status for children of exiting parent
was wrong, but mostly unnoticed when all children were reparented to
init(8). When child can be reparented to a different process which
could affect the child' job control state, it was not properly
accounted for in pg_jobc.
- Lockless check for exiting process' parent process group is racy
because nothing prevents the parent from changing its group
membership.
- Exited process is left in the process group, until waited. This
affects other calculations of pg_jobc.
Split handling of job control status on process changing its process
group, and process exiting. Calculate increments and decrements for
pg_jobs by exact checking the orphanage instead of assuming process
group membership for children and parent. Move the call to killjobc()
later under the proctree_lock. Mark exiting process in killjobc()
with a new flag P_TREE_GRPEXITED and skip it for all pg_jobc
calculations after the flag is set.
Add checker that independently recalculates pg_jobc value and compares
it with the memoized process group state. This is enabled under INVARIANTS.
Reviewed by: jilles
Discussed with: kevans
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D26116
This removes a lot of special casing from the VFS layer.
Reviewed by: kib (previous version)
Tested by: pho (previous version)
Differential Revision: https://reviews.freebsd.org/D25612
They trigger for some people, the bug is not obvious, there are no takers
for fixing it, the issue already had to be there for years beforehand and
is low priority.
r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly marked).
Use it in preparation for a general review of all nodes.
This is non-functional change that adds annotations to SYSCTL_NODE and
SYSCTL_PROC nodes using one of the soon-to-be-required flags.
Mark all obvious cases as MPSAFE. All entries that haven't been marked
as MPSAFE before are by default marked as NEEDGIANT
Approved by: kib (mentor, blanket)
Commented by: kib, gallatin, melifaro
Differential Revision: https://reviews.freebsd.org/D23718
After r355784 the td_oncpu field is no longer synchronized by the thread
lock, so the stack capture interrupt cannot be delievered precisely.
Fix this using a loop which drops the thread lock and restarts if the
wrong thread was sampled from the stack capture interrupt handler.
Change the implementation to use a regular interrupt instead of an NMI.
Now that we drop the thread lock, there is no advantage to the latter.
Simplify the KPIs. Remove stack_save_td_running() and add a return
value to stack_save_td(). On platforms that do not support stack
capture of running threads, stack_save_td() returns EOPNOTSUPP. If the
target thread is running in user mode, stack_save_td() returns EBUSY.
Reviewed by: kib
Reported by: mjg, pho
Tested by: pho
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D23355
Filesystems which want to use it in limited capacity can employ the
VOP_UNLOCK_FLAGS macro.
Reviewed by: kib (previous version)
Differential Revision: https://reviews.freebsd.org/D21427
_sleep(9), wakeup(9), sleepqueue(9), et al do not dereference or modify the
channel pointers provided in any way; they are merely used as intptrs into a
dictionary structure to match waiters with wakers. Correctly annotate this
such that _sleep() and wakeup() may be used on const pointers without
invoking ugly patterns like __DECONST(). Plumb const through all of the
underlying sleepqueue bits.
No functional change.
Reviewed by: rlibby
Discussed with: kib, markj
Differential Revision: https://reviews.freebsd.org/D22914
After r352110 the page lock no longer protects a page's identity, so
there is no purpose in locking the page in pmap_mincore(). Instead,
if vm.mincore_mapped is set to the non-default value of 0, re-lookup
the page after acquiring its object lock, which holds the page's
identity stable.
The change removes the last callers of vm_page_pa_tryrelock(), so
remove it.
Reviewed by: kib
Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D21823
In case the implementation ever changes from using a chain of next pointers,
then changing the macro definition will be necessary, but changing all the
files that iterate over vm_map entries will not.
Drop a counter in vm_object.c that would have an effect only if the
vm_map entry count was wrong.
Discussed with: alc
Reviewed by: markj
Tested by: pho (earlier version)
Differential Revision: https://reviews.freebsd.org/D21882
It is not needed by anything in the kernel and it slightly drives up contention
on both proctree and allproc locks.
Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21447
This allows replacing "sys/eventfilter.h" includes with "sys/_eventfilter.h"
in other header files (e.g., sys/{bus,conf,cpu}.h) and reduces header
pollution substantially.
EVENTHANDLER_DECLARE and EVENTHANDLER_LIST_DECLAREs were moved out of .c
files into appropriate headers (e.g., sys/proc.h, powernv/opal.h).
As a side effect of reduced header pollution, many .c files and headers no
longer contain needed definitions. The remainder of the patch addresses
adding appropriate includes to fix those files.
LOCK_DEBUG and LOCK_FILE_LINE_ARG are moved to sys/_lock.h, as required by
sys/mutex.h since r326106 (but silently protected by header pollution prior
to this change).
No functional change (intended). Of course, any out of tree modules that
relied on header pollution for sys/eventhandler.h, sys/lock.h, or
sys/mutex.h inclusion need to be fixed. __FreeBSD_version has been bumped.
r340744 broke the NFSv4 client, because it replaced pfind_locked() with a
call to pfind(), since pfind() acquires the sx lock for the pid hash and
the NFSv4 already holds a mutex when it does the call.
The patch fixes the problem by recreating a pfind_any_locked() and adding the
functions pidhash_slockall() and pidhash_sunlockall to acquire/release
all of the pid hash locks.
These functions are then used by the NFSv4 client instead of acquiring
the allproc_lock and calling pfind().
Reviewed by: kib, mjg
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D19887
Note that only entries wired by userspace are shown as such. In
particular, entries transiently wired by sysctl_wire_old_buffer() are
not flagged as wired in procstat -v output.
Reviewed by: kib (previous version)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D19461
Otherwise the lock might recurse in faultin() if the process is
swapped out.
Reported by: zeising
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
SVN r340744 erroneously changed pfind() to return any process including
zombies and pfind_any() to return only non-zombie processes.
In particular, this caused kill() on a zombie process to fail with [ESRCH].
There is no direct test case for this but /usr/tests/bin/sh/builtins/kill1.0
occasionally triggers it (as reported by lwhsu).
Conversely, returning zombies from pfind() seems likely to violate
invariants and cause panics, but I have not looked at this.
PR: 233646
Reviewed by: mjg, kib, ngie
Differential Revision: https://reviews.freebsd.org/D18665
Currently unique pid allocation on fork often requires a full walk of
process, group, session lists to make sure it is not used by anything.
This has a side effect of requiring proctree to be held along with allproc,
which adds more contention in poudriere -j 128.
The patch below implements trivial bitmaps which gets rid of the problem.
Dedicated lock is introduced to manage IDs.
While here a bug was discovered: all processes would inherit reap id from
the first process spawned by init. This had a side effect of keeping the
ID used and when allocation rolls over to the beginning it keeps being
skipped.
The patch is loosely based on initial work by mjoras@.
Reviewed by: kib
Sponsored by: The FreeBSD Foundation
This applies the fix in r283924 to the vm.objects sysctl
added by r283624 so the output will include the vnode
information (i.e. path) for tmpfs objects.
Reviewed by: kib, dab
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D2724
waitpid always takes proctree to evaluate the list, but only takes allproc
if it can reap. With this patch allproc is no longer taken, which helps during
poudriere -j 128.
Discussed with: kib
Sponsored by: The FreeBSD Foundation
forks, exits and waits are frequently stalled during poudriere -j 128 runs
due to killpg and process list exports performed for each package.
Both uses take the allproc lock. The latter case can be modified to iterate
over the hash with finer grained locking instead.
Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D17817
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
For some reason the proc UMA zone's ctor, dtor and init functions are
instrumented, but these functions are always available through FBT.
Moreover, the probes are not part of the original Solaris proc
provider, aren't documented, have no uses (e.g., in dwatch(8)) and
have no clear use to begin with. Therefore, remove them.
Reviewed by: rpaulo
Differential Revision: https://reviews.freebsd.org/D2169
