First, this commit is a NOP on GCC <= 4.x; this decidedly doesn't work
cleanly on GCC 4.2, and it will be gone soon anyways so I chose not to dump
time into figuring out if there's a way to make it work. xtoolchain-gcc,
clocking in as GCC6, can cope with it just fine and later versions are also
generally ok with the syntax. I suspect very few users are running GCC4.2
built worlds and also experiencing potential fallout from the status quo.
For dynamically linked applications, this change also means very little.
rtld will run libc ctors before most others, so the situation is
approximately a NOP for these as well.
The real cause for this change is statically linked applications doing
almost questionable things in their constructors. qemu-user-static, for
instance, creates a thread in a global constructor for their async rcu
callbacks. In general, this works in other places-
- On OpenBSD, __stack_chk_guard is stored in an .openbsd.randomdata section
that's initialized by the kernel in the static case, or ld.so in the
dynamic case
- On Linux, __stack_chk_guard is apparently stored in TLS and such a problem
is circumvented there because the value is presumed stable in the new
thread.
On FreeBSD, the rcu thread creation ctor and __guard_setup are both unmarked
priority. qemu-user-static spins up the rcu thread prior to __guard_setup
which starts making function calls- some of these are sprinkled with the
canary. In the middle of one of these functions, __guard_setup is invoked in
the main thread and __stack_chk_guard changes- qemu-user-static is promptly
terminated for an SSP violation that didn't actually happen.
This is not an all-too-common problem. We circumvent it here by giving the
__stack_chk_guard constructor a solid priority. 200 was chosen because that
gives static applications ample range (down to 101) for working around it
if they really need to. I suspect most applications will "just work" as
expected- the default/non-prioritized flavor of __constructor__ functions
run last, and the canary is generally not expected to change as of this
point at the very least.
This took approximately three weeks of spare time debugging to pin down.
PR: 241905
When we do a daopen, we call dareprobe and wait for the results. The repoll runs
the da state machine up through the DA_STATE_RC* and then exits.
For removable media, we poll the device every 3 seconds with a TUR to see if it
has disappeared. This introduces a race. If the removable device has lots of
partitions, and if it's a little slow (like say a USB2 connected USB stick),
then we can have a fair amount of time that this reporbe is going on for. If,
during that time, damediapoll fires, it calls daschedule which changes the
scheduling priority from NONE to NORMAL. When that happens, the careful single
stepping in the da state machine is disrupted and we wind up sceduling multiple
read capacity calls. The first one succeeds and releases the reference. The
second one succeeds and releases the reference (and panics if the right code is
compiled into the da driver).
To avoid the race, only do the TUR calls while in state normal, otherwise just
reschedule damediapoll. This prevents the race from happening.
ccr(4) and TLS support in cxgbe(4) construct key contexts used by the
crypto engine in the T6. This consolidates some duplicated code for
helper functions used to build key contexts.
Reviewed by: np
MFC after: 1 month
Sponsored by: Chelsio Communications
Differential Revision: https://reviews.freebsd.org/D22156
Instead of calloc()ing (and forgetting to free) in a tight loop, just put
this small array on the stack.
Reported by: Coverity
Coverity CID: 1331665
MFC after: 2 weeks
Sponsored by: Axcient
sesutil would allow the user to toggle an LED that was one past the maximum
element. If he tried, ENCIOC_GETELMSTAT would return EINVAL.
Reported by: Coverity
Coverity CID: 1398940
MFC after: 2 weeks
Sponsored by: Axcient
This ensures that a bootstrap clang compiler is always installed as cc
in WORLDTMP. If it is only installed as 'clang' then /usr/bin/cc is
used during the build instead of the bootstrap compiler.
Reviewed by: imp
MFC after: 1 month
Sponsored by: DARPA
Differential Revision: https://reviews.freebsd.org/D22332
At the end of both mevent_add() and mevent_update(), mevent_notify()
is called to wakeup the I/O thread, that will call kevent(changelist)
to update the kernel.
A race condition is possible where the client calls mevent_add() and
mevent_update(EV_ENABLE) before the I/O thread has the chance to wake
up and call mevent_build()+kevent(changelist) in response to mevent_add().
The mevent_add() is therefore ignored by the I/O thread, and
kevent(fd, EV_ENABLE) is called before kevent(fd, EV_ADD), resuliting
in a failure of the kevent(fd, EV_ENABLE) call.
PR: 241808
Reviewed by: jhb, markj
MFC with: r354288
Differential Revision: https://reviews.freebsd.org/D22286
Disable the use of executable 2M page mappings in EPT-format page
tables on affected CPUs. For bhyve virtual machines, this effectively
disables all use of superpage mappings on affected CPUs. The
vm.pmap.allow_2m_x_ept sysctl can be set to override the default and
enable mappings on affected CPUs.
Alternate approaches have been suggested, but at present we do not
believe the complexity is warranted for typical bhyve's use cases.
Reviewed by: alc, emaste, markj, scottl
Security: CVE-2018-12207
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21884
struct nvdimm_label_index is dynamically sized, with the `free`
bitfield expanding to hold `slot_cnt` entries. Fix a few places
where we were treating the struct as though it had a fixed sized.
Reviewed by: cem
Approved by: scottl (mentor)
MFC after: 1 week
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D22253
Save the address of the trap frame in %ebp on kernel entry. This
automatically provides it in struct i386_frame.f_frame to unwinder.
While there, more accurately handle the terminating frames,
Reviewed by: avg, markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D22321
Apply the same user accessible filter to namespaces as is applied
to full-SPA devices. Also, explicitly filter out control region
SPAs which don't expose the nvdimm data area.
Reviewed by: cem
Approved by: scottl (mentor)
MFC after: 1 week
Sponsored by: Intel Corporation
Differential Revision: https://reviews.freebsd.org/D21987
to the size of hardware gdt.
Reviewed by: jhb, markj
Tested by: pho
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D22302
In ip6_[direct_]input() we are looping over the extension headers
to deal with the next header. We pass a pointer to an mbuf pointer
to the handling functions. In certain cases the mbuf can be updated
there and we need to pass the new one back. That missing in
dest6_input() and route6_input(). In tcp6_input() we should also
update it before we call tcp_input().
In addition to that mark the mbuf NULL all the times when we return
that we are done with handling the packet and no next header should
be checked (IPPROTO_DONE). This will eventually allow us to assert
proper behaviour and catch the above kind of errors more easily,
expecting *mp to always be set.
This change is extracted from a larger patch and not an exhaustive
change across the entire stack yet.
PR: 240135
Reported by: prabhakar.lakhera gmail.com
MFC after: 3 weeks
Sponsored by: Netflix
The igmp stats tend to print two lines of warning for an unexpected
version and length. Despite an invalid version and struct size it
continues to try to do something with the data. Do not try to parse
the remainder of the struct and error on warning.
Note the underlying issue of the data not being available properly
is still there and needs to be fixed seperately.
Reported by: test cases, lwhsu
MFC after: 3 weeks
Currently NMIs are sent over event channels, but that defeats the
purpose of NMIs since event channels can be masked. Fix this by
issuing NMIs using a hypercall, which injects a NMI (vector #2) to the
desired vCPU.
Note that NMIs could also be triggered using the emulated local APIC,
but using a hypercall is better from a performance point of view
since it doesn't involve instruction decoding when not using x2APIC
mode.
Reported and Tested by: avg
Sponsored by: Citrix Systems R&D
In our case the structure is more complex and simple static initializer
will upset compiler diagnostics - using memset is still better than building
more complext initializer.
The code for "netstat -gs -f inet" failed if the kernel namelist did not
include the _mrtstat symbol. However, that symbol is not in a standard
kernel even with the ip_mroute module loaded, where the functionality is
available. It is also not in a kernel with MROUTING but also VIMAGE, as
there can be multiple sets of stats. However, when running the command
on a live system, the symbol is not used; a sysctl is used. Go ahead
and try the sysctl in any case, and complain that IPv4 MROUTING is not
present only if the sysctl fails with ENOENT. Also fail if _mrtstat is
not defined when running on a core file; netstat doesn't know about vnets,
so can only work if MROUTING was included, and VIMAGE was not.
Reviewed by: bz
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D22311
On some AMD CPUs, in particular, machines that do not implement
CLFLUSHOPT but do provide CLFLUSH, the CLFLUSH instruction is only
synchronized with MFENCE.
Code using CLFLUSH typicall needs to brace it with MFENCE both before
and after flush, see for instance pmap_invalidate_cache_range(). If
context switch occurs while inside the protected region, we need to
ensure visibility of flushes done on the old CPU, to new CPU.
For all other machines, locked operation done to lock switched thread,
should be enough. For case of different address spaces, reload of
%cr3 is serializing.
Reviewed by: cem, jhb, scottph
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D22007
Suppose a writing thread has pinned its pages and gone to sleep with
pipe_map.cnt > 0. Suppose that the thread is woken up by a signal (so
error != 0) and the other end of the pipe has simultaneously been
closed. In this case, to satisfy the assertion about pipe_map.cnt in
pipe_destroy_write_buffer(), we must mark the buffer as empty.
Reported by: syzbot+5cce271bf2cb1b1e1876@syzkaller.appspotmail.com
Reviewed by: kib
Tested by: pho
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D22261
This change removes TRAP_INTERRUPT and TRAP_TIMERINT frame types.
Their names are a bit confusing: trap + interrupt, what is that?
The TRAP_TIMERINT name is too specific -- can it only be used for timer
"trap-interrupts"? What is so special about them?
My understanding of the code is that INTERRUPT, TRAP_INTERRUPT and
TRAP_TIMERINT differ only in how an offset from callee's frame pointer to a
trap frame on the stack is calculated. And that depends on a number of
arguments that a special handler passes to a callee (a function with a
normal C calling convention).
So, this change makes that logic explicit and collapses all interrupt frame
types into the INTERRUPT type.
Reviewed by: markj
Discussed with: kib, jhb
MFC after: 3 weeks
Differential Revision: https://reviews.freebsd.org/D22303
[libc++] Harden usage of static_assert against C++03
In C++03, we emulate static_assert with a macro, and we must
parenthesize multiple arguments.
llvm-svn: 373328
This is a follow-up to r354460, which causes errors for pre-C++11
programs using <cmath>, similar to:
/usr/include/c++/v1/cmath:622:68: error: too many arguments provided to
function-like macro invocation
Reported by: antoine
MFC after: immediately (because of ports breakage)
If cu reads an EOF on the input side, it goes into a tight loop
sending a garbage byte to the remote. With this change, it exits
gracefully, along with its child.
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
For the PROBEWP and PROBERC* states, add assertiosn that both the da device
state is in the right state, as well as the ccb state is the right one when we
enter dadone_probe{wp,rc}. This will ensure that we don't sneak through when
we're re-probing the size and write protection status of the device and thereby
leak a reference which can later lead to an invalidated peripheral going away
before all references are released (and resulting panic).
Reviewed by: scottl, ken
Differential Revision: https://reviews.freebsd.org/D22295
There are contexts where releasing the ccb triggers dastart() to be run
inline. When da was written, there was always a deferral, so it didn't matter
much. Now, with direct dispatch, we can call dastart from the dadone*
routines. If the probe state isn't updated, then dastart will redo things with
stale information. This normally isn't a problem, because we run the probe state
machine once at boot... Except that we also run it for each open of the device,
which means we can have multiple threads racing each other to try to kick off
the probe. However, if we update the state before we release the CCB, we can
avoid the race. While it's needed only for the probewp and proberc* states, do
it everywhere because it won't hurt the other places.
The race here happens because we reprobe dozens of times on boot when drives
have lots of partitions. We should consider caching this info for 1-2 seconds
to avoid this thundering hurd.
Reviewed by: scottl, ken
Differential Revision: https://reviews.freebsd.org/D22295
Besides the confusing name, this type is effectively unused.
In all cases where it could be set, the INTERRUPT type is set by the
earlier code. The conditions for TRAP_INTERRUPT are a subset of the
conditions for INTERRUPT.
Reviewed by: kib, markj
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D22305
exploits the sparsity of allocated blocks in a range, without
issuing an "are you there?" query for every block in the range.
swap_pager_copy() is not so smart. Modify the implementation
of swap_pager_meta_free() slightly so that swap_pager_copy()
can use that smarter implementation too.
Based on an observation of: Yoshihiro Ota (ota_j.email.ne.jp)
Reviewed by: kib,alc
Tested by: pho
Differential Revision: https://reviews.freebsd.org/D22280
to the PCB hash. The function doesn't modify the hash. It always
asserted write lock historically, but with epoch conversion this
fails in some special cases.
Reviewed by: rwatson, bz
Reported-by: syzbot+0b0488ca537e20cb2429@syzkaller.appspotmail.com
When reporting a process' stats, we can't just provide the tty as an
unsigned long, as if we have no controlling tty, the tty would be NODEV, or
-1. Instaed, just special-case NODEV.
Submitted by: Juraj Lutter <otis@sk.FreeBSD.org>
MFC after: 1 week
Don't depend on CPUTYPE to define powerpcspe CFLAGS, they should be set
unconditionally. This reduces duplication. Also, set some CFLAGS as
gcc-only, because clang's SPE support always uses the SPE ABI, it's not an
optional feature.
