The CPU succeeding in releasing the not last reference can still have pending
stores to the object protected by the affected counter. This opens a time
window where another CPU can release the last reference and free the object,
resulting in use-after-free. On top of that this prevents the compiler from
generating more accesses to the object regardless of how atomic_fcmpset_rel_int
is implemented (of course as long as it provides the release semantic).
Reviewed by: markj
Key and cookie management typically wants to
avoid information leaks by explicitly zeroing
before free. This routine simplifies that by
permitting consumers to do so without carrying
the size around.
Reviewed by: jeff@, jhb@
MFC after: 1 week
Sponsored by: Rubicon Communications, LLC (Netgate)
Differential Revision: https://reviews.freebsd.org/D22790
As written now, it copies random kernel memory from beyond the bounds
of the array.
Reported and tested by: pho
Reviewed by: markj
Sponsored by: The FreeBSD Foundation (kib)
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D23694
Assert that sema[idx] allocation from sem[] is sane.
Also assert that sem_mtx is owned, it protects the SEM_ALLOC flag.
Reviewed by: markj
Tested by: pho
Sponsored by: The FreeBSD Foundation (kib)
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D23694
Fix the following -Werror warning from clang 10.0.0 in hptmv(4):
sys/dev/hptmv/ioctl.c:240:4: error: misleading indentation; statement is not part of the previous 'if' [-Werror,-Wmisleading-indentation]
_vbus_p=pArray->pVBus;
^
sys/dev/hptmv/ioctl.c:237:10: note: previous statement is here
if(!mIsArray(pArray))
^
This is because the return statement after the if statement was not
indented. (Note that this file has been idented assuming 4-space tabs.)
MFC after: 3 days
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.
Reviewed by: kib
Approved by: kib (mentor)
Differential Revision: https://reviews.freebsd.org/D23625
X-Generally looks fine: jhb
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.
Reviewed by: hselasky, kib, zeising
Approved by: kib (mentor)
Differential Revision: https://reviews.freebsd.org/D23631
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.
Reviewed by: hselasky, kib
Approved by: kib (mentor)
Differential Revision: https://reviews.freebsd.org/D23632
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.
Reviewed by: kib, trasz
Approved by: kib (mentor)
Differential Revision: https://reviews.freebsd.org/D23640
sys/dev/hptmv/ioctl.c:240:4: error: misleading indentation; statement is not part of the previous 'if' [-Werror,-Wmisleading-indentation]
_vbus_p=pArray->pVBus;
^
sys/dev/hptmv/ioctl.c:237:10: note: previous statement is here
if(!mIsArray(pArray))
^
This is because the return statement after the if statement was not
indented. (Note that this file has been idented assuming 4-space tabs.)
MFC after: 3 days
It's valid for a periph to be removed with outstanding transactions on the
device. In CAM, multiple periphs attach to a single device. There's no interlock
to prevent one of these going away while other periphs have outstanding CCBs and
it's not an error either. Remove this overly agressive KASSERT to prevent
false-positive panics when devices depart.
At the time opt-in was introduced adding yourself as a writer was esrializing
across the mount point. Nowadays it is fully per-cpu, the only impact being
a small single-threaded hit on top of what's there right now.
Vast majority of the overhead stems from the call to VOP_GETWRITEMOUNT which
has is done regardless.
Should someone want to microoptimize this single-threaded they can coalesce
looking the mount up with adding a write to it.
bintime()/binuptime().
The algorithm to read the consistent snapshot of current timehand is
repeated in each accessor, including the details proper rollup
detection and synchronization with the writer. In fact there are only
two different kind of readers: one for bintime()/binuptime() which has
to do the in-place calculation, and another kind which fetches some
member from struct timehand.
Extract the logic into type-checked macros, GETTHBINTIME() for bintime
calculation, and GETTHMEMBER() for safe read of a structure' member.
This way, the synchronization is only written in bintime_off() and
getthmember().
In bintime_off(), use overflow-safe calculation of th_scale *
delta(timecounter). In tc_windup, pre-calculate the min delta value
which overflows and require slow algorithm, into the new timehands
th_large_delta member.
This part with overflow fix was written by Bruce Evans.
Reported by: Mark Millard <marklmi@yahoo.com> (the overflow issue)
Tested by: pho
Discussed with: emaste
Sponsored by: The FreeBSD Foundation (kib)
MFC after: 3 weeks
Returned value has type based on the argument, meaning consumers no longer
have to cast in the commmon case.
This commit keeps the kernel compilable without patching the rest.
Assert on not specifying any of the (soon to be) required flags as well
as specifying both of them.
Pointed out by: cem, hselasky
Reviewed by: hselasky, kib
Approved by: kib (mentor)
Differential Revision: https://reviews.freebsd.org/D23678
this replaces the following near the syscall exit:
cmp $0x39,%rax
ja 0xffffffff8108f82c
movabs $0x200001800060005,%rcx
bt %rax,%rcx
jae 0xffffffff8108f82c
with:
test %edi,%edi
jne 0xffffffff8091a49c
This in particular significantly shortens amd64_syscall, which otherwise
keeps jumping forward over 2KB of code in total.
Note some of these branches should be either eliminated altogether or
coalesced.
The latter is a typedef of the former; the typedef exists and these bits are
representing vmprot values, so use the correct type.
Submitted by: sigsys@gmail.com
MFC after: 3 days
know that if there are any outstanding CCBs, then when they dereference the path
that's freed at the bottom of camperiphfree there will be some flavor of
panic. This moves that eventual panic to a traceback of when we free the last
reference on the device, which is earlier but may not be early enough.
