This gets rid of the error prone naming where fget_unlocked returns with
a ref held, while fget_locked requires a lock but provides nothing in
terms of making sure the file lives past unlock.
No functional changes.
Without this change, unmounting smbfs filesystems with an INVARIANTS
kernel would panic after 10e64782ed.
Found by: markj
Reviewed by: markj, jhb
Obtained from: CheriBSD
MFC after: 3 days
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D32492
fspacectl(2) is a system call to provide space management support to
userspace applications. VOP_DEALLOCATE(9) is a VOP call to perform the
deallocation. vn_deallocate(9) is a public KPI for kmods' use.
The purpose of proposing a new system call, a KPI and a VOP call is to
allow bhyve or other hypervisor monitors to emulate the behavior of SCSI
UNMAP/NVMe DEALLOCATE on a plain file.
fspacectl(2) comprises of cmd and flags parameters to specify the
space management operation to be performed. Currently cmd has to be
SPACECTL_DEALLOC, and flags has to be 0.
fo_fspacectl is added to fileops.
VOP_DEALLOCATE(9) is added as a new VOP call. A trivial implementation
of VOP_DEALLOCATE(9) is provided.
Sponsored by: The FreeBSD Foundation
Reviewed by: kib
Differential Revision: https://reviews.freebsd.org/D28347
The kern_poll_kfds() operates on clear kernel data, kfds points to an
array in the kernel, while kern_poll() operates on user supplied pollfd.
Move nfds check to kern_poll_maxfds().
No functional changes, it's for future use in the Linux emulation layer.
Reviewd by: kib
Differential Revision: https://reviews.freebsd.org/D30690
MFC after: 2 weeks
This follows select by eleminating the use of filedesc lock.
This is a win for single-threaded processes and a mixed bag for others
as at small concurrency it is faster to take the lock instead of
refing/unrefing each file descriptor.
Nonetheless, removal of shared lock usage is a step towards a
mtx-protected fd table.
Since most select users are single-threaded this avoid a lot of work
in the common case.
For example select of 16 fds (ops/s):
before: 2114536
after: 2991010
eventfd is a Linux system call that produces special file descriptors
for event notification. When porting Linux software, it is currently
usually emulated by epoll-shim on top of kqueues. Unfortunately, kqueues
are not passable between processes. And, as noted by the author of
epoll-shim, even if they were, the library state would also have to be
passed somehow. This came up when debugging strange HW video decode
failures in Firefox. A native implementation would avoid these problems
and help with porting Linux software.
Since we now already have an eventfd implementation in the kernel (for
the Linuxulator), it's pretty easy to expose it natively, which is what
this patch does.
Submitted by: greg@unrelenting.technology
Reviewed by: markj (previous version)
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D26668
Prior to the patch returning selfdfree could still be racing against doselwakeup
which set sf_si = NULL and now locks stp to wake up the other thread.
A sufficiently unlucky pair can end up going all the way down to freeing
select-related structures before the lock/wakeup/unlock finishes.
This started manifesting itself as crashes since select data started getting
freed in r367714.
Refcounting was added to combat a race between selfdfree and doselwakup,
but it adds avoidable overhead.
selfdfree detects it can free the object by ->sf_si == NULL, thus we can
ensure that the condition only holds after all accesses are completed.
On a sample box vmstat -z shows:
ITEM SIZE LIMIT USED FREE REQ
64: 64, 0, 1043784, 4367538,3698187229
selfd: 64, 0, 1520, 13726,182729008
But at the same time:
vm.uma.selfd.keg.domain.1.pages: 121
vm.uma.selfd.keg.domain.0.pages: 121
Thus 242 pages got pulled even though the malloc zone would likely accomodate
the load without using extra memory.
It keeps recalculated way more often than it is needed.
Provide a routine (fdlastfile) to get it if necessary.
Consumers may be better off with a bitmap iterator instead.
Hide debug print showing use of sign extended ioctl command argument
under INVARIANTS. The print is available to all and can easily fill
up the logs.
No functional change intended.
MFC after: 1 week
Sponsored by: Mellanox Technologies
This opens the door for other descriptor types to implement
posix_fallocate(2) as needed.
Reviewed by: kib, bcr (manpages)
Differential Revision: https://reviews.freebsd.org/D23042
vn_write already checks for vnode type to see if bwillwrite should be called.
This effectively reverts r244643.
Reviewed by: kib
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D21905
fget_unlocked() and fhold().
On sufficiently large machine, f_count can be legitimately very large,
e.g. malicious code can dup same fd up to the per-process
filedescriptors limit, and then fork as much as it can.
On some smaller machine, I see
kern.maxfilesperproc: 939132
kern.maxprocperuid: 34203
which already overflows u_int. More, the malicious code can create
transient references by sending fds over unix sockets.
I realized that this check is missed after reading
https://secfault-security.com/blog/FreeBSD-SA-1902.fd.html
Reviewed by: markj (previous version), mjg
Tested by: pho (previous version)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D20947
The comment isn't stale. The check is bogus in the sense that poll(2)
does not require pollfd entries to be unique in fd space, so there is no
reason there cannot be more pollfd entries than open or even allowed
fds. The check is mostly a seatbelt against accidental misuse or
abuse. FD_SETSIZE, while usually unrelated to poll, is used as an
arbitrary floor for systems with very low kern.maxfilesperproc.
Additionally, document this possible EINVAL condition in the poll.2
manual.
No functional change.
Reviewed by: markj
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D17671
Some of the poll code used 'fds' and some used 'ufds' to refer to the
uap->fds userspace pointer that was passed around to subroutines. Some of
the poll code used 'fds' to refer to the kernel memory pollfd arrays, which
seemed unnecessarily confusing.
Unify on 'ufds' to refer to the userspace pollfd array.
Additionally, 'bits' is not an accurate description of the kernel pollfd
array in kern_poll, so rename that to 'kfds'. Finally, clean up some logic
with mallocarray() and nitems().
No functional change.
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D17670
- Add macros to allow preinitialization of cap_rights_t.
- Convert most commonly used code paths to use preinitialized cap_rights_t.
A 3.6% speedup in fstat was measured with this change.
Reported by: mjg
Reviewed by: oshogbo
Approved by: sbruno
MFC after: 1 month
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
A correct destruction is important for WITNESS(4) and LOCK_PROFILING(9).
Submitted by: Sebastian Huber <sebastian.huber@embedded-brains.de>
MFC after: 1 week
Mainly focus on files that use BSD 3-Clause license.
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.
Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.
of their sys_*() counterparts. The svr4 is left unchanged.
Reviewed by: kib@
MFC after: 2 weeks
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D9379
read(2), write(2), dup(2), and mmap(2). This auditing is not
required by the Common Criteria (and hence was not being
performed), but is valuable in both contemporary live analysis
and forensic use cases.
MFC after: 3 days
Sponsored by: DARPA, AFRL
Previously, freebsd32 binaries could submit read/write requests with lengths
greater than INT_MAX that a native kernel would have rejected.
Reviewed by: kib
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D5788
- Set td_errno so that ktrace and dtrace can obtain the syscall error
number in the usual way.
- Pass negative error numbers directly to the syscall layer, as they're
not intended to be returned to userland.
Reviewed by: kib
Sponsored by: EMC / Isilon Storage Division
Differential Revision: https://reviews.freebsd.org/D5425
loop finds the selfd entry and clears its sf_si pointer, which is
handled by selfdfree() in parallel, NULL sf_si makes selfdfree() free
the memory. The result is the race and accesses to the freed memory.
Refcount the selfd ownership. One reference is for the sf_link
linkage, which is unconditionally dereferenced by selfdfree().
Another reference is for sf_threads, both selfdfree() and
doselwakeup() race to deref it, the winner unlinks and than frees the
selfd entry.
Reported by: Larry Rosenman <ler@lerctr.org>
Tested by: Larry Rosenman <ler@lerctr.org>, pho
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
pwrite(2) syscalls are wrapped to provide compatibility with pre-7.x
kernels which required padding before the off_t parameter. The
fcntl(2) contains compatibility code to handle kernels before the
struct flock was changed during the 8.x CURRENT development. The
shims were reasonable to allow easier revert to the older kernel at
that time.
Now, two or three major releases later, shims do not serve any
purpose. Such old kernels cannot handle current libc, so revert the
compatibility code.
Make padded syscalls support conditional under the COMPAT6 config
option. For COMPAT32, the syscalls were under COMPAT6 already.
Remove WITHOUT_SYSCALL_COMPAT build option, which only purpose was to
(partially) disable the removed shims.
Reviewed by: jhb, imp (previous versions)
Discussed with: peter
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Introduce fget_fcntl which performs appropriate checks when needed.
This removes a branch from fget_unlocked.
Introduce fget_mmap dealing with cap_rights_to_vmprot conversion.
This removes a branch from _fget.
Modify fget_unlocked to pass sequence counter to interested callers so
that they can perform their own checks and make sure the result was
otained from stable & current state.
Reviewed by: silence on -hackers
especially for platforms where unaligned access is not allowed. Make
it possible to override the small buffer size.
A simple continuous read string test using libusb showed a reduction
in CPU usage from roughly 10% to less than 1% using a dual-core GHz
CPU, when the malloc() operation was skipped for small buffers.
MFC after: 2 weeks
fd_lastfile is guaranteed to be the biggest open fd, so when the intent
is to iterate over active fds or lookup one, there is no point in looking
beyond that limit.
Few places are left unpatched for now.
MFC after: 1 week
SBT_MAX, to make it more robust in case internal type representation will
change in the future. All the consumers were migrated to SBT_MAX and
every new consumer (if any) should from now use this interface.
Requested by: bapt, jmg, Ryan Lortie (implictly)
Reviewed by: mav, bde
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
