Use the new kern.stacktop sysctl to retrieve the address of stack top
instead of kern.usrstack. kern.usrstack does not have any knowledge
of the stack gap, so this can cause problems with thread stacks.
Using kern.stacktop sysctl should fix most of those problems.
kern.usrstack is used as a fallback when kern.stacktop cannot be read.
Rename usrstack variables to stacktop to reflect this change.
Fixes problems with firefox and thunderbird not starting with
stack gap enabled.
PR: 239873
Reviewed by: kib
Obtained from: Semihalf
Sponsored by: Stormshield
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D31898
Describe internal allocations, mention problems with the use of global
malloc(3) and the reasons for internal allocator existence.
Document shared objects implementation and describe shortcomings of the
chosen approach, as well as the rationale why it was done that way.
Reviewed by: markj
Discussed with: jilles
Sponsored by: The FreeBSD Foundation
MFC after: 3 days
Differential revision: https://reviews.freebsd.org/D32243
I got the following error with an ASAN-instrument libthr:
==803==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fffffffcdb0 at pc 0x000801863396 bp 0x7ff8
READ of size 4 at 0x7fffffffcdb0 thread T0
#0 0x801863395 in handle_signal /local/scratch/alr48/cheri/freebsd/lib/libthr/thread/thr_sig.c:262:2
#1 0x801860da2 in thr_sighandler /local/scratch/alr48/cheri/freebsd/lib/libthr/thread/thr_sig.c:246:2
Address 0x7fffffffcdb0 is located in stack of thread T0 at offset 208 in frame
#0 0x80186080f in thr_sighandler /local/scratch/alr48/cheri/freebsd/lib/libthr/thread/thr_sig.c:213
This frame has 1 object(s):
[32, 64) 'act' (line 216) <== Memory access at offset 208 overflows this variable
HINT: this may be a false positive if your program uses some custom stack
This seems like a false-positive since the line in question is
`SIGSETOR(actp->sa_mask, ucp->uc_sigmask);` and it complains about a read
operation (from the ucontext_t argument) so this indicates to me that ASAN
does not understand that thr_sighandler() is a signal handler.
Differential Revision: https://reviews.freebsd.org/D31074
Right now, libthr does not initialize RtldLockInfo.rtli_version when calling
_rtld_thread_init(), which makes versioning the interface troublesome.
Add a workaround: if the calling object of _rtld_thread_init() exports
the "_pli_rtli_version" symbol, then consider rtli_version initialized.
Otherwise, forcibly set it to RTLI_VERSION_ONE, currently defined as
RTLI_VERSION.
Export "_pli_rtli_version" from libthr and properly initialize rtli_version.
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D29633
This was only needed on 32-bit arm prior to ARMv6. As we only support
ARMv6 or later remove it.
Reviewed by: mannu
Sponsored by: Innovate UK
Differential Revision: https://reviews.freebsd.org/D29624
This warning is very rarely useful (inline is a hint and not mandatory).
This flag results in many warnings being printed when compiling C++
code that uses the standard library with GCC.
This flag was originally added in back in r94332 but the flag is a no-op
in Clang ("This diagnostic flag exists for GCC compatibility, and has no
effect in Clang"). Removing it should make the GCC build output slightly
more readable.
Reviewed By: jrtc27, imp
Differential Revision: https://reviews.freebsd.org/D29235
One possible way the recursion can happen is during fork: suppose
that fork is called from early code that did not triggered
jemalloc(3) initialization yet. Then we lock thr_malloc lock, and
call malloc_prefork() that might require initialization of jemalloc
pthread_mutexes, calling into libthr malloc. It is safe to allow
recursion for this occurence.
PR: 252579
Reported by: Vasily Postnicov <shamaz.mazum@gmail.com>
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Without wrapping, rtld services and malloc(3) are not guaranteed
to operate correctly in the forked child.
Reviewed by: markj
MFC after: 1 week
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D28088
Follow-up to r353959 and r368070: do the same for other architectures.
arm32 already seems to use its own .fnstart/.fnend directives, which
appear to be ARM-specific variants of the same thing. Likewise, MIPS
uses .frame directives.
Reviewed by: arichardson
Differential Revision: https://reviews.freebsd.org/D27387
We need at least thr_malloc ready. The situation is possible e.g. in case
of libthr being listed in DT_NEEDED before some of its consumers.
Reported and tested by: lev
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
This seems to be required by recent clang asan.
I do not see other way than put the symbol under FBSD_1.0 version.
PR: 251112
Reported by: Andrew Stitcher <astitcher@apache.org>
Reviewed by: emaste
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D27389
Specifically, if we're waking up some value n > BATCH_SIZE, then the
copyin(9) is wrong on the second iteration due to upp being the wrong type.
upp is currently a uint32_t**, so upp + pos advances it by twice as many
elements as it should (host pointer size vs. compat32 pointer size).
Fix it by just making upp a uint32_t*; it's still technically a double
pointer, but the distinction doesn't matter all that much here since we're
just doing arithmetic on it.
Add a test case that demonstrates the problem, placed with the libthr tests
since one messing with _umtx_op should be running these tests. Running under
compat32, the new test case will hang as threads after the first 128 get
missed in the wake. it's not immediately clear how to hit it in practice,
since pthread_cond_broadcast() uses a smaller (sleepq batch?) size observed
to be around ~50 -- I did not spend much time digging into it.
The uintptr_t change makes no functional difference, but i've tossed it in
since it's more accurate (semantically).
Reported by: Andrew Gierth (andrew_tao173.riddles.org.uk, inspection)
Reviewed by: kib
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D27231
The current default is provided in various Makefile.inc in some top-level
directories and covers a good portion of the tree, but doesn't cover parts
of the build a little deeper (e.g. libcasper).
Provide a default in src.sys.mk and set WARNS to it in bsd.sys.mk if that
variable is defined. This lets us relatively cleanly provide a default WARNS
no matter where you're building in the src tree without breaking things
outside of the tree.
Crunchgen has been updated as a bootstrap tool to work on this change
because it needs r365605 at a minimum to succeed. The cleanup necessary to
successfully walk over this change on WITHOUT_CLEAN builds has been added.
There is a supplemental project to this to list all of the warnings that are
encountered when the environment has WARNS=6 NO_WERROR=yes:
https://warns.kevans.dev -- this project will hopefully eventually go away
in favor of CI doing a much better job than it.
Reviewed by: emaste, brooks, ngie (all earlier version)
Reviewed by: emaste, arichardson (depend-cleanup.sh change)
Differential Revision: https://reviews.freebsd.org/D26455
pthread_get_name_np() and pthread_set_name_np().
This re-applies r361770 after compatibility fixes.
Reviewed by: antoine, jkim, markj
Tested by: antoine (exp-run)
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D25117
for pthread_get_name_np() and pthread_set_name_np(), to be
compatible with Linux.
PR: 238404
Proposed and reviewed by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D25117
Assume gcc is at least 6.4, the oldest xtoolchain in the ports tree.
Assume clang is at least 6, which was in 11.2-RELEASE. Drop conditions
for older compilers.
Reviewed by: imp (earlier version), emaste, jhb
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
Differential Revision: https://reviews.freebsd.org/D24802
functionality first appeared in FreeBSD.
Submitted by: Gordon Bergling gbergling_gmail.com
Approved by: bcr
Differential Revision: https://reviews.freebsd.org/D24677
The function allows to peek at the thread exit status and even see
return value, without joining (and thus finally destroying) the target
thread.
Reviewed by: markj
Sponsored by: The FreeBSD Foundation (kib)
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D23676
exited but not yet joined thread.
Before, if the thread exited but was not yet joined, we returned
ESRCH.
According to IEEE Std 1003.1™-2017 recommendation in the
description of pthread_cancel(3):
If an implementation detects use of a thread ID after the end of its
lifetime, it is recommended that the function should fail and report
an [ESRCH] error.
So it seems desirable to not return ESRCH until the lifetime of the
thread ID ends. According to the section 2.9.2 Thread IDs,
The lifetime of a thread ID ends after the thread terminates if it
was created with the detachstate attribute set to
PTHREAD_CREATE_DETACHED or if pthread_detach() or pthread_join()
has been called for that thread.
In other words, lifetime for thread ID of exited but not yet joined thread
did not ended yet.
Prompted by: cperciva
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Ensure proper handshake to transfer sigfastblock(2) blocking word
ownership from rtld to libthr.
Unfortunately sigfastblock(2) is not enough to stop intercepting
signals in libthr, because critical sections must ensure more than
just signal blocking.
Tested by: pho
Disscussed with: cem, emaste, jilles
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D12773
Update a bunch of Makefile.depend files as
a result of adding Makefile.depend.options files
Reviewed by: bdrewery
MFC after: 1 week
Sponsored by: Juniper Networks
Differential Revision: https://reviews.freebsd.org/D22494
Compiling with clang gives a loss-of-alignment error due the cast to
uint8_t *. Since the TLS is always tcb aligned and TP_OFFSET is defined
as sizeof(struct tcb) we can guarantee there is no misalignment. Silence
the error by moving the offset into the inline assembly.
Reviewed by: br
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D21926
If robust mutex' owner terminated, causing kernel-assisted state
recovery, and then pthread_mutex_destroy() is executed as the next
action, assert is triggered about mutex still being on the list.
Ignore the mutex linkage in pthread_mutex_destroy() for shared robust
mutexes with dead owner, same as for enqueue_mutex().
Reported by: avg
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
As per r177853, we need to avoid using errno inside user mutex code, since
signal handlers can interfere with it and mess up libthr internal state.
So, implement _umtx_op_err() instead, which makes a raw syscall and
returns the error value directly instead of using errno.
Approved by: jhibbits (mentor)
Differential Revision: https://reviews.freebsd.org/D20946
In some corner cases of static linking and unexpected libraries order
on the linker command line, libc symbol might preempt the same libthr
symbol, in which case libthr jump table points back to libc causing
either infinite recursion or loop. Handle all of such symbols by
using private libthr names for them, ensuring that the right pointers
are installed into the table.
In collaboration with: arichardson
PR: 239475
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21088
In some corner cases of static linking and unexpected libraries order
on the linker command line, libc symbol might preempt the same libthr
symbol, in which case libthr jump table points back to libc causing
either infinite recursion or loop. Handle all of such symbols by
using private libthr names for them, ensuring that the right pointers
are installed into the table.
In collaboration with: arichardson
PR: 239475
Tested by: pho
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D21088
If dso uses initial exec TLS mode, rtld tries to allocate TLS in
static space. If there is no space left, the dlopen(3) fails. If space
if allocated, initial content from PT_TLS segment is distributed to
all threads' pcbs, which was missed and caused un-initialized TLS
segment for such dso after dlopen(3).
The mode is auto-detected either due to the relocation used, or if the
DF_STATIC_TLS dynamic flag is set. In the later case, the TLS segment
is tried to allocate earlier, which increases chance of the dlopen(3)
to succeed. LLD was recently fixed to properly emit the flag, ld.bdf
did it always.
Initial test by: dumbbell
Tested by: emaste (amd64), ian (arm)
Tested by: Gerald Aryeetey <aryeeteygerald_rogers.com> (arm64)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D19072
r345620 by kib@ fixed the rtld issue that caused a crash at startup
during resolution of libc's ifuncs with BIND_NOW.
PR: 233333
Sponsored by: The FreeBSD Foundation
This is not required of a compliant implementation, but it's easy to
check for and helps improve compatibility with other common
implementations. Moreover, it's consistent with our
pthread_mutex_destroy().
PR: 234805
Reviewed by: jhb, kib, ngie
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D19496
When libthr is statically linked into the binary, order of the
constructors execution is not deterministic. It is possible for the
application constructor to use pthread_mutex_* functions before the
libthr initialization was done.
Handle it by:
- making thr_malloc.c locking functions operational when curthread is not
yet set;
- making __thr_malloc_init() idempotent, allowing more than one call to it;
- unconditionally calling __thr_malloc_init() before initializing
a process-private mutex.
Reported and tested by: mmel
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
The need to use libc malloc(3) from some places in libthr always
caused issues. For instance, per-thread key allocation was switched to
use plain mmap(2) to get storage, because some third party mallocs
used keys for implementation of calloc(3).
Even more important, libthr calls calloc(3) during initialization of
pthread mutexes, and jemalloc uses pthread mutexes. Jemalloc provides
some way to both postpone the initialization, and to make
initialization to use specialized allocator, but this is very fragile
and often breaks. See the referenced PR for another example.
Add the small malloc implementation used by rtld, to libthr. Use it in
thr_spec.c and for mutexes initialization. This avoids the issues with
mutual dependencies between malloc and libthr in principle. The
drawback is that some more allocations are not interceptable for
alternate malloc implementations. There should be not too much memory
use from this allocator, and the alternative, direct use of mmap(2) is
obviously worse.
PR: 235211
MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation
Differential revision: https://reviews.freebsd.org/D18988
An issue remains with BIND_NOW and processes using threads. For now,
restore libc's BIND_NOW disable, and also disable BIND_NOW in rtld and
libthr.
A patch is in review (D18400) that likely fixes this issue, but just
disable BIND_NOW pending further testing after it is committed.
PR: 233333
Sponsored by: The FreeBSD Foundation
Also remove logic to avoid unnecessary stores to the global variable.
Thread creation and destruction are heavy enough that any supposed savings
is in the noise.
MFC after: 2 weeks
Sponsored by: Dell EMC Isilon
This basically adds makes use of the C99 restrict keyword, and also
adds some 'const's to four threading functions: pthread_mutexattr_gettype(),
pthread_mutexattr_getprioceiling(), pthread_mutexattr_getprotocol(), and
pthread_mutex_getprioceiling. The changes are in accordance to POSIX/SUSv4-2018.
Hinted by: DragonFlyBSD
Relnotes: yes
MFC after: 1 month
Differential Revision: D16722
The function retrieves the thread name previously set by
pthread_set_name_np(3). The name is cached in the process memory.
Requested by: Willem Jan Withagen <wjw@digiware.nl>
Man page update: Yuri Pankov <yuripv@yuripv.net>
Reviewed by: ian (previous version)
Discussed with: arichardson, bjk (man page)
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Differential revision: https://reviews.freebsd.org/D16702
