Some Linux interfaces never restart after being interrupted by a signal
handler, regardless of the use of SA_RESTART [1]. It means that for
pthread cancellation, if the target thread disables cancellation with
pthread_setcancelstate and calls such interfaces (like poll or select),
it should not see spurious EINTR failures due the internal SIGCANCEL.
However recent changes made pthread_cancel to always sent the internal
signal, regardless of the target thread cancellation status or type.
To fix it, the previous semantic is restored, where the cancel signal
is only sent if the target thread has cancelation enabled in
asynchronous mode.
The cancel state and cancel type is moved back to cancelhandling
and atomic operation are used to synchronize between threads. The
patch essentially revert the following commits:
8c1c0aae20 nptl: Move cancel type out of cancelhandling
2b51742531 nptl: Move cancel state out of cancelhandling
26cfbb7162 nptl: Remove CANCELING_BITMASK
However I changed the atomic operation to follow the internal C11
semantic and removed the MACRO usage, it simplifies a bit the
resulting code (and removes another usage of the old atomic macros).
Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
and powerpc64-linux-gnu.
[1] https://man7.org/linux/man-pages/man7/signal.7.html
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
(cherry-picked from commit 404656009b)
<limits.h> used to be a header file with no declarations.
GCC's libgomp includes it in a #pragma GCC visibility hidden block.
Including <unistd.h> from <limits.h> (indirectly) declares everything
in <unistd.h> with hidden visibility, resulting in linker failures.
This commit avoids C declarations in assembler mode and only declares
__sysconf in <limits.h> (and not the entire contents of <unistd.h>).
The __sysconf symbol is already part of the ABI. PTHREAD_STACK_MIN
is no longer defined for __USE_DYNAMIC_STACK_SIZE && __ASSEMBLER__
because there is no possible definition.
Additionally, PTHREAD_STACK_MIN is now defined by <pthread.h> for
__USE_MISC because this is what developers expect based on the macro
name. It also helps to avoid libgomp linker failures in GCC because
libgomp includes <pthread.h> before its visibility hacks.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
As a result, is not necessary to specify __attribute__ ((nocommon))
on individual definitions.
GCC 10 defaults to -fno-common on all architectures except ARC,
but this change is compatible with older GCC versions and ARC, too.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This slightly reduces code size, as can be seen below.
__libc_lock_unlock is usually used along with __libc_lock_lock in
the same function. __libc_lock_lock already has an out-of-line
slow path, so this change should not introduce many additional
non-leaf functions.
This change also fixes a link failure in 32-bit Arm thumb mode
because commit 1f9c804fbd
("nptl: Use internal low-level lock type for !IS_IN (libc)")
introduced __libc_do_syscall calls outside of libc.
Before x86-64:
text data bss dec hex filename
1937748 20456 54896 2013100 1eb7ac libc.so.6
25601 856 12768 39225 9939 nss/libnss_db.so.2
40310 952 25144 66406 10366 nss/libnss_files.so.2
After x86-64:
text data bss dec hex filename
1935312 20456 54896 2010664 1eae28 libc.so.6
25559 864 12768 39191 9917 nss/libnss_db.so.2
39764 960 25144 65868 1014c nss/libnss_files.so.2
Before i686:
2110961 11272 39144 2161377 20fae1 libc.so.6
27243 428 12652 40323 9d83 nss/libnss_db.so.2
43062 476 25028 68566 10bd6 nss/libnss_files.so.2
After i686:
2107347 11272 39144 2157763 20ecc3 libc.so.6
26929 432 12652 40013 9c4d nss/libnss_db.so.2
43132 480 25028 68640 10c20 nss/libnss_files.so.2
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This avoids an ABI hazard (types changing between different modules
of glibc) without introducing linknamespace issues. In particular,
NSS modules now call __lll_lock_wait_private@@GLIBC_PRIVATE to wait
on internal locks (the unlock path is inlined and performs a direct
system call).
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The symbols gai_cancel, gai_error, gai_suspend, getaddrinfo_a,
__gai_suspend_time64 were moved using scripts/move-symbol-to-libc.py.
For Hurd (which remains !PTHREAD_IN_LIBC), a few #define redirects
had to be added because several pthread functions are not available
under __. (Linux uses __ prefixes for most hidden aliases, and has
to in some cases to avoid linknamespace issues.)
The valgrind/helgrind test suite needs a way to make stack dealloction
more prompt, and this feature seems to be generally useful.
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
librt.so is no longer installed for PTHREAD_IN_LIBC, and tests
are not linked against it. $(librt) is introduced globally for
shared tests that need to be linked for both PTHREAD_IN_LIBC
and !PTHREAD_IN_LIBC.
GLIBC_PRIVATE symbols that were needed during the transition are
removed again.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This adds several temporary GLIBC_PRIVATE exports. The symbol names
are changed so that they all start with __timer_.
It is now possible to invoke the fork handler directly, so
pthread_atfork is no longer necessary. The associated error cannot
happen anymore, and cancellation handling can be removed from
the helper thread routine.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The symbol was moved using scripts/move-symbol-to-libc.py.
An explicit call from fork into the mq_notify implementation replaces
the previous use of pthread_atfork.
Reviewed-by: Adhemerva Zanella <adhemerval.zanella@linaro.org>
This commit also moves the aio_misc and aio_sigquue helper,
so GLIBC_PRIVATE exports need to be added.
The symbol was moved using scripts/move-symbol-to-libc.py.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The pthread_atfork is similar between Linux and Hurd, only the compat
version bits differs. The generic version is place at sysdeps/pthread
with a common name.
It also fixes an issue with Hurd license, where the static-only object
did not use LGPL + exception.
Checked on x86_64-linux-gnu, i686-linux-gnu, and with a build for
i686-gnu.
The Linux nptl implementation is used as base for generic fork
implementation to handle the internal locks and mutexes. The
system specific bits are moved a new internal _Fork symbol.
(This new implementation will be used to provide a async-signal-safe
_Fork now that POSIX has clarified that fork might not be
async-signal-safe [1]).
For Hurd it means that the __nss_database_fork_prepare_parent and
__nss_database_fork_subprocess will be run in a slight different
order.
[1] https://austingroupbugs.net/view.php?id=62
For !__ASSUME_TIME64_SYSCALLS there is no need to issue a 64-bit syscall
if the provided timeout fits in a 32-bit one. The 64-bit usage should
be rare since the timeout is a relative one.
Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel
(with and without --enable-kernel=5.1) and on x86_64-linux-gnu.
Reviewed-by: Lukasz Majewski <lukma@denx.de>
This mirrors the situation on Hurd. These directories are on
the include search part, so #include <pthreadP.h> works after this
change on both Hurd and nptl.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
A new build flag, _TIME_BITS, enables the usage of the newer 64-bit
time symbols for legacy ABI (where 32-bit time_t is default). The 64
bit time support is only enabled if LFS (_FILE_OFFSET_BITS=64) is
also used.
Different than LFS support, the y2038 symbols are added only for the
required ABIs (armhf, csky, hppa, i386, m68k, microblaze, mips32,
mips64-n32, nios2, powerpc32, sparc32, s390-32, and sh). The ABIs with
64-bit time support are unchanged, both for symbol and types
redirection.
On Linux the full 64-bit time support requires a minimum of kernel
version v5.1. Otherwise, the 32-bit fallbacks are used and might
results in error with overflow return code (EOVERFLOW).
The i686-gnu does not yet support 64-bit time.
This patch exports following rediretions to support 64-bit time:
* libc:
adjtime
adjtimex
clock_adjtime
clock_getres
clock_gettime
clock_nanosleep
clock_settime
cnd_timedwait
ctime
ctime_r
difftime
fstat
fstatat
futimens
futimes
futimesat
getitimer
getrusage
gettimeofday
gmtime
gmtime_r
localtime
localtime_r
lstat_time
lutimes
mktime
msgctl
mtx_timedlock
nanosleep
nanosleep
ntp_gettime
ntp_gettimex
ppoll
pselec
pselect
pthread_clockjoin_np
pthread_cond_clockwait
pthread_cond_timedwait
pthread_mutex_clocklock
pthread_mutex_timedlock
pthread_rwlock_clockrdlock
pthread_rwlock_clockwrlock
pthread_rwlock_timedrdlock
pthread_rwlock_timedwrlock
pthread_timedjoin_np
recvmmsg
sched_rr_get_interval
select
sem_clockwait
semctl
semtimedop
sem_timedwait
setitimer
settimeofday
shmctl
sigtimedwait
stat
thrd_sleep
time
timegm
timerfd_gettime
timerfd_settime
timespec_get
utime
utimensat
utimes
utimes
wait3
wait4
* librt:
aio_suspend
mq_timedreceive
mq_timedsend
timer_gettime
timer_settime
* libanl:
gai_suspend
Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
Now that the thread cancellation type is not accessed concurrently
anymore, it is possible to move it out the cancelhandling.
By removing the cancel state out of the internal thread cancel handling
state there is no need to check if cancelled bit was set in CAS
operation.
It allows simplifing the cancellation wrappers and the
CANCEL_CANCELED_AND_ASYNCHRONOUS is removed.
Checked on x86_64-linux-gnu and aarch64-linux-gnu.
Now that thread cancellation state is not accessed concurrently anymore,
it is possible to move it out the 'cancelhandling'.
The code is also simplified: CANCELLATION_P is replaced with a
internal pthread_testcancel call and the CANCELSTATE_BIT{MASK} is
removed.
With this behavior pthread_setcancelstate does not require to act on
cancellation if cancel type is asynchronous (is already handled either
by pthread_setcanceltype or by the signal handler).
Checked on x86_64-linux-gnu and aarch64-linux-gnu.
Only the placeholder compatibility symbols are left now.
The __errno_location symbol was removed (moved) using
scripts/move-symbol-to-libc.py.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The symbols were moved using scripts/move-symbol-to-libc.py.
The libpthread placeholder symbols need some changes because some
symbol versions have gone away completely. But
__errno_location@@GLIBC_2.0 still exists, so the GLIBC_2.0 version
is still there.
The internal __pthread_create symbol now points to the correct
function, so the sysdeps/nptl/thrd_create.c override is no longer
necessary.
There was an issue how the hidden alias of pthread_getattr_default_np
was defined, so this commit cleans up that aspects and removes the
GLIBC_PRIVATE export altogether.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Use the __nptl_tls_static_size_for_stack inline function instead,
and the GLRO (dl_tls_static_align) value directly.
The computation of GLRO (dl_tls_static_align) in
_dl_determine_tlsoffset ensures that the alignment is at least
TLS_TCB_ALIGN, which at least STACK_ALIGN (see allocate_stack).
Therefore, the additional rounding-up step is removed.
ALso move the initialization of the default stack size from
__pthread_initialize_minimal_internal to __pthread_early_init.
This introduces an extra system call during single-threaded startup,
but this simplifies the initialization sequence. No locking is
needed around the writes to __default_pthread_attr because the
process is single-threaded at this point.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The initialization of the report_events TCB field is now performed
in __tls_init_tp instead of __pthread_initialize_minimal_internal
(in libpthread).
The events interface is difficult to test because GDB stopped using it
in 2015. The td_thr_get_info change to ignore lookup issues is enough
to support GDB with this change.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Permissions of the cached stacks may have to be updated if an object
is loaded that requires executable stacks, so the dynamic loader
needs to know about these cached stacks.
The move of in_flight_stack and stack_cache_actsize is a requirement for
merging __reclaim_stacks into the fork implementation in libc.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This is an early variant of __tls_init_tp, primarily for initializing
thread-related elements of _rtld_global/GL.
Some existing initialization code not needed for NPTL is moved into
the generic version of this function.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
If libpthread is included in libc, it is not necessary to delay
initialization of the lock/unlock function pointers until libpthread
is loaded. This eliminates two unprotected function pointers
from _rtld_global and removes some initialization code from
libpthread.
Tested-by: Carlos O'Donell <carlos@redhat.com>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Previously, the source file nptl/cancellation.c was compiled multiple
times, for libc, libpthread, librt. This commit switches to a single
implementation, with new __pthread_enable_asynccancel@@GLIBC_PRIVATE,
__pthread_disable_asynccancel@@GLIBC_PRIVATE exports.
The almost-unused CANCEL_ASYNC and CANCEL_RESET macros are replaced
by LIBC_CANCEL_ASYNC and LIBC_CANCEL_ASYNC macros. They call the
__pthread_* functions unconditionally now. The macros are still
needed because shared code uses them; Hurd has different definitions.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
And deprecate it in <pthread.h>, redirecting it to sched_yield
for the time being.
The symbol was moved using scripts/move-symbol-to-libc.py.
No GLIBC_2.34 symbol version is added because of the compatibility
symbol status.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
And __pthread_rwlock_trywrlock as a compatibility symbol.
Remove the unused __libc_rwlock_trywrlock macro.
The symbols were moved using scripts/move-symbol-to-libc.py.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
And __pthread_rwlock_tryrdlock as a compatibility symbol.
Remove the unused __libc_rwlock_tryrdlock macro.
The symbols were moved using scripts/move-symbol-to-libc.py.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
And __pthread_rwlock_init as a compatibility symbol.
__libc_rwlock_init is changed to call __pthread_rwlock_init directly.
The symbols were moved using scripts/move-symbol-to-libc.py.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
And __pthread_rwlock_destroy as a compatibility symbol.
rwlocks do not need finalization, so change __libc_rwlock_fini to do
nothing.
The symbols were moved using scripts/move-symbol-to-libc.py.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
The symbol was moved using scripts/move-symbol-to-libc.py.
The calls to __pthread_mutex_init, __pthread_mutexattr_init,
__pthread_mutexattr_settype are now private and no longer need
to be exported. This allows the removal of the newly added
GLIBC_2.34 symbol versions for those functions.
Also clean up some weak declarations in <libc-lockP.h> for
these functions. They are not needed and potentially incorrect
for static linking of mtx_init.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
The symbol was moved using scripts/move-symbol-to-libc.py.
This change also turns __pthread_once into a compatibility symbol
because after the call_once move, an internal call to __pthread_once
can be used. This an adjustment to __libc_once: Outside libc (e.g.,
in nscd), it has to call pthread_once. With __pthread_once as a
compatibility symbol, it is no longer to add a new GLIBC_2.34
version after the move from libpthread, and this commit removes
the new __pthread_once@@GLIBC_2.34 version.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
GCC 11 warns when a pointer to an uninitialized object is passed
to a function that takes a const-qualified argument. This is done
on the assumption that most such functions read from the object.
For the rare case of a function that doesn't, GCC 11 extends
attribute access to add a new mode called none.
POSIX pthread_setspecific() is one such rare function that takes
a const void* argument but that doesn't read from the object it
points to. To suppress the -Wmaybe-uninitialized issued by GCC
11 when the address of an uninitialized object is passed to it
(e.g., the result of malloc()), this change #defines
__attr_access_none in cdefs.h and uses the macro on the function
in sysdeps/htl/pthread.h and sysdeps/nptl/pthread.h.
This is required for GCC versions before 10 which default to -fcommon.
Fixes commit 442e8a40da ("nptl: Move part
of TCB initialization from libpthread to __tls_init_tp").
The signal handler is exported as __nptl_setxid_sighandler, so
that the libpthread initialization code can install it. This
is sufficient for now because it is guarantueed to happen before
the first pthread_create call.
Onl pthread_cond_clockwait did not have a forwarder, so it needs
a new symbol version.
Some complications arise due to the need to supply hidden aliases,
GLIBC_PRIVATE exports (for the C11 condition variable implementation
that still remains in libpthread) and 64-bit time_t stubs.
pthread_cond_broadcast, pthread_cond_signal, pthread_cond_timedwait,
pthread_cond_wait, pthread_cond_clockwait have been moved using
scripts/move-symbol-to-libc.py.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This is complicated because of a second compilation of
nptl/pthread_mutex_lock.c via nptl/pthread_mutex_cond_lock.c.
PTHREAD_MUTEX_VERSIONS is introduced to suppress symbol versions
in that case.
The symbols __pthread_mutex_lock, __pthread_mutex_unlock,
__pthread_mutex_init, __pthread_mutex_destroy, pthread_mutex_lock,
pthread_mutex_unlock, pthread_mutex_init, pthread_mutex_destroy
have been moved using scripts/move-symbol-to-libc.py.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This is in preparation of moving the mutex code into libc.
__pthread_tunables_init is now called via __pthread_early_init.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The forwarders were only used internally, so new symbol versions
are needed. All symbols are moved at once because the forwarders
are no-ops if libpthread is not loaded, leading to inconsistencies
in case of a partial migration.
The symbols __pthread_rwlock_rdlock, __pthread_rwlock_unlock,
__pthread_rwlock_wrlock, pthread_rwlock_rdlock,
pthread_rwlock_unlock, pthread_rwlock_wrlock have been moved using
scripts/move-symbol-to-libc.py.
The __ symbol variants are turned into compat symbols, which is why they
do not receive a GLIBC_2.34 version.
