Lower the amd64 shared page, which contains the signal trampoline,
from the top of user memory to one page lower on machines with the
Ryzen (AMD Family 17h) CPU. This pushes ps_strings and the stack
down by one page as well. On Ryzen there is some sort of interaction
between code running at the top of user memory address space and
interrupts that can cause FreeBSD to either hang or silently reset.
This sounds similar to the problem found with DragonFly BSD that
was fixed with this commit:
https://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/b48dd28447fc8ef62fbc963accd301557fd9ac20
but our signal trampoline location was already lower than the address
that DragonFly moved their signal trampoline to. It also does not
appear to be related to SMT as described here:
https://www.phoronix.com/forums/forum/hardware/processors-memory/955368-some-ryzen-linux-users-are-facing-issues-with-heavy-compilation-loads?p=955498#post955498
"Hi, Matt Dillon here. Yes, I did find what I believe to be a
hardware issue with Ryzen related to concurrent operations. In a
nutshell, for any given hyperthread pair, if one hyperthread is
in a cpu-bound loop of any kind (can be in user mode), and the
other hyperthread is returning from an interrupt via IRETQ, the
hyperthread issuing the IRETQ can stall indefinitely until the
other hyperthread with the cpu-bound loop pauses (aka HLT until
next interrupt). After this situation occurs, the system appears
to destabilize. The situation does not occur if the cpu-bound
loop is on a different core than the core doing the IRETQ. The
%rip the IRETQ returns to (e.g. userland %rip address) matters a
*LOT*. The problem occurs more often with high %rip addresses
such as near the top of the user stack, which is where DragonFly's
signal trampoline traditionally resides. So a user program taking
a signal on one thread while another thread is cpu-bound can cause
this behavior. Changing the location of the signal trampoline
makes it more difficult to reproduce the problem. I have not
been because the able to completely mitigate it. When a cpu-thread
stalls in this manner it appears to stall INSIDE the microcode
for IRETQ. It doesn't make it to the return pc, and the cpu thread
cannot take any IPIs or other hardware interrupts while in this
state."
since the system instability has been observed on FreeBSD with SMT
disabled. Interrupts to appear to play a factor since running a
signal-intensive process on the first CPU core, which handles most
of the interrupts on my machine, is far more likely to trigger the
problem than running such a process on any other core.
Also lower sv_maxuser to prevent a malicious user from using mmap()
to load and execute code in the top page of user memory that was made
available when the shared page was moved down.
Make the same changes to the 64-bit Linux emulator.
PR: 219399
Reported by: [email protected]
Reviewed by: kib
Reviewed by: dchagin (previous version)
Tested by: [email protected] (earlier version)
Differential Revision: https://reviews.freebsd.org/D11780
In r246085 some bits that are MI movied out into headers in compat/linux,
but I missed that when I commited x86_64 Linuxulator. So remove the duplicates.
Drop the "created from" line from files generated by makesyscalls.sh.
This information is less useful when the generated files are included in
source control along with the source. If needed it can be reconstructed
from the $FreeBSD$ tag in the generated file. Removing this information
from the generated output permits committing the generated files along
with the change to the system call master list without having inconsistent
metadata in the generated files.
Regenerate the affected files along with the MFC.
Reduce code duplication between MD Linux code by moving SYSV IPC 64-bit
related struct definitions out into the MI path.
Invert the native ipc structs to the Linux ipc structs convesion logic.
Since 64-bit variant of ipc structs has more precision convert native ipc
structs to the 64-bit Linux ipc structs and then truncate 64-bit values
into the non 64-bit if needed. Unlike Linux, return EOVERFLOW if the
values do not fit.
Fix SYSV IPC for 64-bit Linuxulator which never sets IPC_64 bit.
Trying to be more compatible with Linux if.h definitions:
- renaming l_ifreq::ifru_metric to l_ifreq::ifru_ivalue;
- adding a definition for ifr_ifindex which points to l_ifreq::ifru_ivalue.
A quick search indicates that Linux already got the above changes since 2.1.14.
Reviewed by: kib, marcel, dchagin
Change Linux epoll_pwait syscall definition to match Linux actual one.
MFC r314313:
Regen for r314312 (Linux epoll_pwait).
MFC r314314:
Return EINVAL in case when an invalid size of signal mask specified.
Don't create pointless backups of generated files in "make sysent".
Any sensible workflow will include a revision control system from which
to restore the old files if required. In normal usage, developers just
have to clean up the mess.
Update syscall.master to 4.10-rc6. Also fix comments, a typo,
and wrong numbering for a few unimplemented syscalls.
For 32-bit Linuxulator, socketcall() syscall was historically
the entry point for the sockets API. Starting in Linux 4.3, direct
syscalls are provided for the sockets API. Enable it.
The initial version of patch was provided by trasz@ and extended by me.
MFC r313285:
Regen after r313284.
MFC r313684:
Fix r313284.
Members of the syscall argument structures are padded to a word size. So,
for COMPAT_LINUX32 we should convert user supplied system call arguments
which is 32-bit in that case to the array of register_t.
MFC r313912:
Finish r313684.
Convert linux_recv(), linux_send() and linux_accept() system call arguments
to the register_t type too.
Fix a copy/paste bug introduced during X86_64 Linuxulator work.
FreeBSD support NX bit on X86_64 processors out of the box, for i386 emulation
use READ_IMPLIES_EXEC flag, introduced in r302515.
While here move common part of mmap() and mprotect() code to the files in compat/linux
to reduce code dupcliation between Linuxulator's
Approved by: re (gjb)
Implement Linux personality() system call mainly due to READ_IMPLIES_EXEC flag.
In Linux if this flag is set, PROT_READ implies PROT_EXEC for mmap().
Linux/i386 set this flag automatically if the binary requires executable stack.
READ_IMPLIES_EXEC flag will be used in the next Linux mmap() commit.
Approved by: re (gjb)
kern.features.linux: 1 meaning linux 32 bits binaries are supported
kern.features.linux64: 1 meaning linux 64 bits binaries are supported
The goal here is to help 3rd party applications (including ports) to determine
if the host do support linux emulation
Reviewed by: dchagin
MFC after: 1 week
Relnotes: yes
Differential Revision: D5830
POSIX requires these members to be of type void * rather than the
char * inherited from 4BSD. NetBSD and OpenBSD both changed their
fields to void * back in 1998. No new build failures were reported
via an exp-run.
PR: 206503 (exp-run)
Reviewed by: kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D5092
AT_SECURE auxv entry has been added to the Linux 2.5 kernel to pass a
boolean flag indicating whether secure mode should be enabled. 1 means
that the program has changes its credentials during the execution.
Being exported AT_SECURE used by glibc issetugid() call.
Submitted by: imp, dchagin
Security: FreeBSD-SA-16:10.linux
Security: CVE-2016-1883
The set_robust_list system call request the kernel to record the head
of the list of robust futexes owned by the calling thread. The head
argument is the list head to record.
The get_robust_list system call should return the head of the robust
list of the thread whose thread id is specified in pid argument.
The list head should be stored in the location pointed to by head
argument.
In contrast, our implemenattion of get_robust_list system call copies
the known portion of memory pointed by recorded in set_robust_list
system call pointer to the head of the robust list to the location
pointed by head argument.
So, it is possible for a local attacker to read portions of kernel
memory, which may result in a privilege escalation.
Submitted by: mjg
Security: SA-16:03.linux
sysent.
sv_prepsyscall is unused.
sv_sigsize and sv_sigtbl translate signal number from the FreeBSD
namespace into the ABI domain. It is only utilized on i386 for iBCS2
binaries. The issue with this approach is that signals for iBCS2 were
delivered with the FreeBSD signal frame layout, which does not follow
iBCS2. The same note is true for any other potential user if
sv_sigtbl. In other words, if ABI needs signal number translation, it
really needs custom sv_sendsig method instead.
Sponsored by: The FreeBSD Foundation
linux_syscallnames[] from linux_* to linux32_* to avoid conflicts with
linux64.ko. While here, add support for linux64 binaries to systrace.
- Update NOPROTO entries in amd64/linux/syscalls.master to match the
main table to fix systrace build.
- Add a special case for union l_semun arguments to the systrace
generation.
- The systrace_linux32 module now only builds the systrace_linux32.ko.
module on amd64.
- Add a new systrace_linux module that builds on both i386 and amd64.
For i386 it builds the existing systrace_linux.ko. For amd64 it
builds a systrace_linux.ko for 64-bit binaries.
Reviewed by: markj
Differential Revision: https://reviews.freebsd.org/D3954
Due to an off by one the code would read an entry past the table, as
opposed to the last entry which contains the nosys handler.
Reported by: Pawel Biernacki <pawel.biernacki gmail.com>
Don Lewis