sysctl(9): Ease exporting struct sizes; Discourage doing that

Introduce two helpers, the more general SYSCTL_SIZEOF() and
a struct-specific one SYSCTL_SIZEOF_STRUCT() which prepends 'struct' in
the

sysctl(9): Ease exporting struct sizes; Discourage doing that

Introduce two helpers, the more general SYSCTL_SIZEOF() and
a struct-specific one SYSCTL_SIZEOF_STRUCT() which prepends 'struct' in
the description and in the use of sizeof() but uses the raw structure
name as the knob's name. The size of the object/structure is exported
under 'debug.sizeof'.

Existing knobs under 'debug.sizeof' were all converted to use the
helpers.

Add a note before the helpers discouraging the introduction of new
leaves for ad-hoc reasons. List alternative means for developers to
obtain the size of arbitrary kernel structures easily (thanks to markj@
for providing these).

No functional change (intended).

Reviewed by: kib, markj
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D50121

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devfs: Return early from sysctl_devname() if no input is given

Otherwise we end up searching for a device using an uninitialized key,
tripping up KMSAN.

MFC after: 2 weeks

devfs: add integrity asserts for cdevp_list

It's possible for misuse of cdev KPIs or for bugs in devfs itself to
result in e.g. a cdev object's container being freed while still on the
global list u

devfs: add integrity asserts for cdevp_list

It's possible for misuse of cdev KPIs or for bugs in devfs itself to
result in e.g. a cdev object's container being freed while still on the
global list used to populate each devfs mount; see PR 273418 for a
recent example.

Since a node may be marked inactive well before it is reaped from the
list, add a new flag solely to track list membership, and employ it in
some basic list integrity assertions to catch bad actors.

Discussed with: kib, mjg
MFC after: 1 week

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sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

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devfs: stop taking the interlock in devfs_delete

It buys nothing now that vhold does not require it.

devfs: retire the unused DEVFS_DEL_VNLOCKED flag

devfs(4): defer freeing until we drop devmtx ("cdev")

Before r332974 the old code would sometimes cause a rare lock order
reversal against pagequeue, which looked roughly like this:

witness_checkor

devfs(4): defer freeing until we drop devmtx ("cdev")

Before r332974 the old code would sometimes cause a rare lock order
reversal against pagequeue, which looked roughly like this:

witness_checkorder()
__mtx_lock-flags()
vm_page_alloc()
uma_small_alloc()
keg_alloc_slab()
keg_fetch-slab()
zone_fetch-slab()
zone_import()
zone_alloc_bucket()
uma_zalloc_arg()
bucket_alloc()
uma_zfree_arg()
free()
devfs_metoo()
devfs_populate_loop()
devfs_populate()
devfs_rioctl()
VOP_IOCTL_APV()
VOP_IOCTL()
vn_ioctl()
fo_ioctl()
kern_ioctl()
sys_ioctl()

Since r332974 the original problem no longer exists, but it still
makes sense to move things out of the - often congested - lock.

Reviewed By: kib, markj
Sponsored by: NetApp, Inc.
Sponsored by: Klara, Inc.
Differential Revision: https://reviews.freebsd.org/D27334

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fs: clean up empty lines in .c and .h files

Merge ^/head r364082 through r364250.

MFH

Sponsored by: Rubicon Communications, LLC (netgate.com)

devfs: Abstract locking assertions

The conversion was largely mechanical: sed(1) with:

-e 's|mtx_assert(&devmtx, MA_OWNED)|dev_lock_assert_locked()|g'
-e 's|mtx_assert(&devmtx, MA_NOTOWNED)|dev

devfs: Abstract locking assertions

The conversion was largely mechanical: sed(1) with:

-e 's|mtx_assert(&devmtx, MA_OWNED)|dev_lock_assert_locked()|g'
-e 's|mtx_assert(&devmtx, MA_NOTOWNED)|dev_lock_assert_unlocked()|g'

The definitions of these abstractions in fs/devfs/devfs_int.h are the
only non-mechanical change.

No functional change.

show more ...

Merge ^/head r364051 through r364081.

devfs: bool -> int

Fixes buildworld after r364069

devfs: save on spurious relocking for devfs_populate

Tested by: pho

Merge ^/head r358269 through r358399.

Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many)

r357614 added CTLFLAG_NEEDGIANT to make it easier to find nodes that are
still not MPSAFE (or already are but aren’t properly mark

Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many)

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

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vfs: drop the mostly unused flags argument from VOP_UNLOCK

Filesystems which want to use it in limited capacity can employ the
VOP_UNLOCK_FLAGS macro.

Reviewed by: kib (previous version)
Differenti

vfs: drop the mostly unused flags argument from VOP_UNLOCK

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

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devfs: introduce a per-dev lock to protect ->si_devsw

This allows bumping threadcount without taking the global devmtx lock.

In particular this eliminates contention on said lock while using bhyve

devfs: introduce a per-dev lock to protect ->si_devsw

This allows bumping threadcount without taking the global devmtx lock.

In particular this eliminates contention on said lock while using bhyve
with multiple vms.

Reviewed by: kib
Tested by: markj
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D22548

show more ...

Merge ^/head r340427 through r340868.

Ensure that directory entry padding bytes are zeroed.

Directory entries must be padded to maintain alignment; in many
filesystems the padding was not initialized, resulting in stack
memory being cop

Ensure that directory entry padding bytes are zeroed.

Directory entries must be padded to maintain alignment; in many
filesystems the padding was not initialized, resulting in stack
memory being copied out to userspace. With the ino64 work there
are also some explicit pad fields in struct dirent. Add a subroutine
to clear these bytes and use it in the in-tree filesystems. The
NFS client is omitted for now as it was fixed separately in r340787.

Reported by: Thomas Barabosch, Fraunhofer FKIE
Reviewed by: kib
MFC after: 3 days
Sponsored by: The FreeBSD Foundation

show more ...

sysctl(9): Ease exporting struct sizes; Discourage doing that

Introduce two helpers, the more general SYSCTL_SIZEOF() and
a struct-specific one SYSCTL_SIZEOF_STRUCT() which prepends 'struct' in
the

sysctl(9): Ease exporting struct sizes; Discourage doing that

Introduce two helpers, the more general SYSCTL_SIZEOF() and
a struct-specific one SYSCTL_SIZEOF_STRUCT() which prepends 'struct' in
the description and in the use of sizeof() but uses the raw structure
name as the knob's name. The size of the object/structure is exported
under 'debug.sizeof'.

Existing knobs under 'debug.sizeof' were all converted to use the
helpers.

Add a note before the helpers discouraging the introduction of new
leaves for ad-hoc reasons. List alternative means for developers to
obtain the size of arbitrary kernel structures easily (thanks to markj@
for providing these).

No functional change (intended).

Reviewed by: kib, markj
MFC after: 3 days
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D50121

show more ...

devfs: Return early from sysctl_devname() if no input is given

Otherwise we end up searching for a device using an uninitialized key,
tripping up KMSAN.

MFC after: 2 weeks

devfs: add integrity asserts for cdevp_list

It's possible for misuse of cdev KPIs or for bugs in devfs itself to
result in e.g. a cdev object's container being freed while still on the
global list u

devfs: add integrity asserts for cdevp_list

It's possible for misuse of cdev KPIs or for bugs in devfs itself to
result in e.g. a cdev object's container being freed while still on the
global list used to populate each devfs mount; see PR 273418 for a
recent example.

Since a node may be marked inactive well before it is reaped from the
list, add a new flag solely to track list membership, and employ it in
some basic list integrity assertions to catch bad actors.

Discussed with: kib, mjg
MFC after: 1 week

show more ...

sys: Remove $FreeBSD$: two-line .h pattern

Remove /^\s*\*\n \*\s+\$FreeBSD\$$\n/