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)
The remaining symbols are mostly used by libthread_db.
__pthread_get_minstack has to remain exported even though unused.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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.
The symbol was moved using scripts/move-symbol-to-libc.py.
A temporary __pthread_testcancel@@GLIBC_PRIVATE export is created
because it is needed by the semaphore implementation.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
I used these shell commands:
../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")
and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
This patch fixes both sem_wait and sem_timedwait cancellation point for
uncontended case. In this scenario only atomics are involved and thus
the futex cancellable call is not issue and a pending cancellation signal
is not handled.
The fix is straighforward by calling pthread_testcancel is both function
start. Although it would be simpler to call CANCELLATION_P directly, I
decided to add an internal pthread_testcancel alias and use it to export
less internal implementation on such function. A possible change on
how pthread_testcancel is internally implemented would lead to either
continue to force use CANCELLATION_P or to adjust its every use.
GLIBC testcase also does have tests for uncontended cases, test-cancel12
and test-cancel14.c, however both are flawed by adding another
cancellation point just after thread pthread_cleanup_pop:
47 static void *
48 tf (void *arg)
49 {
50 pthread_cleanup_push (cleanup, NULL);
51
52 int e = pthread_barrier_wait (&bar);
53 if (e != 0 && e != PTHREAD_BARRIER_SERIAL_THREAD)
54 {
55 puts ("tf: 1st barrier_wait failed");
56 exit (1);
57 }
58
59 /* This call should block and be cancelable. */
60 sem_wait (&sem);
61
62 pthread_cleanup_pop (0);
63
64 puts ("sem_wait returned");
65
66 return NULL;
67 }
So sem_{timed}wait does not act on cancellation, pthread_cleanup_pop executes
'cleanup' and then 'puts' acts on cancellation. Since pthread_cleanup_pop
removed the clean-up handler, it will ran only once and thus it won't accuse
an error to indicate sem_wait has not acted on the cancellation signal.
This patch also fixes this behavior by removing the cancellation point 'puts'.
It also adds some cleanup on all sem_{timed}wait cancel tests.
It partially fixes BZ #18243. Checked on x86_64.
[BZ #18243]
* nptl/pthreadP.h (__pthread_testcancel): Add prototype and hidden_proto.
* nptl/pthread_testcancel.c (pthread_cancel): Add internal aliais
definition.
* nptl/sem_timedwait.c (sem_timedwait): Add cancellation check for
uncontended case.
* nptl/sem_wait.c (__new_sem_wait): Likewise.
* nptl/tst-cancel12.c (cleanup): Remove wrong cancellation point.
(tf): Fix check for uncontended case.
(do_test): Likewise.
* nptl/tst-cancel13.c (cleanup): Remove wrong cancellation point.
(tf): Fix check for uncontended case.
(do_test): Likewise.
* nptl/tst-cancel14.c (cleanup): Remove wrong cancellation point.
(tf): Fix check for uncontended case.
(do_test): Likewise.
* nptl/tst-cancel15.c (cleanup): Remove wrong cancellation point.
(tf): Fix check for uncontended case.
(do_test): Likewise.
2002-11-26 Ulrich Drepper <drepper@redhat.com>
* allocatestack.c (queue_stack): Don't remove stack from list here.
Do it in the caller. Correct condition to prematurely terminate
loop to free stacks.
(__deallocate_stack): Remove stack from list here.
2002-11-26 Ulrich Drepper <drepper@redhat.com>
* Makefile (tests): Add tst-stack1.
* tst-stack1.c: New file.
* allocatestack.c (allocate_stack): Initialize the TCB on a user
provided stack.
* pthread_attr_getstack.c: Return bottom of the thread area.
2002-11-25 Ulrich Drepper <drepper@redhat.com>
* Makefile (libpthread-routines): Add pt-allocrtsig and
pthread_kill_other_threads.
* pt-allocrtsig.c: New file.
* pthread_kill_other_threads.c: New file.
* sysdeps/unix/sysv/linux/allocrtsig.c: Add additional aliases for
all three functions.
* sysdeps/unix/sysv/linux/Makefile (sysdep_routines): Remove
allocrtsig.
* sysdeps/unix/sysv/linux/Versions (libc:GLIBC_PRIVATE): Export
__libc_current_sigrtmin_private, __libc_current_sigrtmax_private,
and __libc_allocate_rtsig_private.
* Versions (libpthread): Export pthread_kill_other_threads_np,
__libc_current_sigrtmin, and __libc_current_sigrtmax.
2002-11-24 Ulrich Drepper <drepper@redhat.com>
* allocatestack.c (allocate_stack): stackaddr in attribute points to
the end of the stack. Adjust computations.
When mprotect call fails dequeue stack and free it.
* pthread_attr_setstack.c: Store top of the stack in stackaddr
attribute.
* pthread_getattr_np.c: Likewise.
* descr.h (IS_DETACHED): Add some more parenthesis to prevent
surprises.
2002-11-23 Ulrich Drepper <drepper@redhat.com>
* sysdeps/pthread/pthread.h (pthread_self): __THROW must come before
attribute definitions. Patch by Luca Barbieri <ldb@ldb.ods.org>.
2002-11-22 Ulrich Drepper <drepper@redhat.com>
* pthread_getspecific.c: Optimize access to first 2nd-level array.
* pthread_setspecific.c: Likewise.
2002-11-21 Ulrich Drepper <drepper@redhat.com>
* sysdeps/unix/sysv/linux/i386/createthread.c: Remove CLONE_ flags
definitions. Get them from the official place.
* sysdeps/unix/sysv/linux/i386/fork.c: Likewise.
* sysdeps/unix/sysv/linux/i386/createthread.c: Update CLONE_* flags.
Use new CLONE_ flags in clone() calls.
* sysdeps/unix/sysv/linux/fork.c: Use ARCH_FORK to actually fork.
* sysdeps/unix/sysv/linux/i386/fork.c: New file.
* Versions: Add pthread_* functions for libc.
* forward.c: New file.
* sysdeps/pthread/Makefile (libpthread-sysdeps_routines): Add
errno-loc.
* herrno.c: New file.
* res.c: New file.
* Makefile (libpthread-routines): Remove sem_post, sem_wait,
sem_trywait, and sem_timedwait. Add herrno and res.
* sem_init.c: Don't initialize lock and waiters members.
* sem_open.c: Likewise.
* sem_post.c: Removed.
* sem_wait.c: Removed.
* sem_trywait.c: Removed.
* sem_timedwait.c: Removed.
* sysdeps/unix/sysv/linux/i386/i486/lowlevelsem.S: Complete rewrite.
Includes full implementations of sem_post, sem_wait, sem_trywait,
and sem_timedwait.
* sysdeps/unix/sysv/linux/i386/lowlevelsem.h (lll_sem_post): Adjust
for new implementation.
* sysdeps/unix/sysv/linux/internaltypes.h (struct sem): Remove lock
and waiters fields.
* tst-sem3.c: Improve error message.
* tst-signal3.c: Likewise.
* init.c (__pthread_initialize_minimal): Use set_tid_address syscall
to tell the kernel about the termination futex and to initialize tid
member. Don't initialize main_thread.
* descr.h (struct pthread): Remove main_thread member.
* cancelllation.c (__do_cancel): Remove code handling main thread.
The main thread is not special anymore.
* allocatestack.c (__reclaim_stacks): Mark stacks as unused. Add
size of the stacks to stack_cache_actsize.
* pt-readv.c: Add missing "defined".
* pt-sigwait.c: Likewise.
* pt-writev.c: Likewise.
2002-11-09 Ulrich Drepper <drepper@redhat.com>
* Versions: Export __connect from libpthread.
Patch by Luca Barbieri <ldb@ldb.ods.org>.
* Makefile (libpthread-routines): Add pt-raise.
* sysdeps/unix/sysv/linux/raise.c: New file.
* sysdeps/unix/sysv/linux/pt-raise.c: New file.
* sysdeps/generic/pt-raise.c: New file.
* pthread_cond_init.c: Initialize all data elements of the condvar
structure. Patch by Luca Barbieri <ldb@ldb.ods.org>.
* pthread_attr_init.c: Actually implement 2.0 compatibility version.
* pthread_create.c: Likewise.
* Makefile (tests): Add tst-key1, tst-key2, tst-key3.
* tst-key1.c: New file.
* tst-key2.c: New file.
* tst-key3.c: New file.
* Versions: Export pthread_detach for version GLIBC_2.0.
Reported by Saurabh Desai <sdesai@austin.ibm.com>.
2002-11-08 Ulrich Drepper <drepper@redhat.com>
* pthread_key_create.c: Terminate search after an unused key was found.
Patch by Luca Barbieri <ldb@ldb.ods.org>.
* sysdeps/unix/sysv/linux/i386/pthread_once.S: Return zero.
Patch by Luca Barbieri <ldb@ldb.ods.org>.
2002-10-10 Ulrich Drepper <drepper@redhat.com>
* sysdeps/unix/sysv/linux/i386/i486/lowlevelsem.S: Use slow generic
dynamic lookup for errno in PIC.
* allocatestack.c (get_cached_stack): Rearrange code slightly to
release the stack lock as soon as possible.
Call _dl_allocate_tls_init for TCB from the cache to re-initialize
the static TLS block.
(allocate_stack): Call _dl_allocate_tls_init for user-provided stack.
* cancellation.c: Renamed from cancelation.c.
* Makefile: Adjust accordingly.
* pthreadP.h (CANCELLATION_P): Renamed from CANCELATION_P.
* cleanup_defer.c: Use CANCELLATION_P.
* pthread_testcancel.c: Likewise.
* descr.h: Fix spelling in comments.
* init.c: Likewise.
* pthread_getattr_np.c: Likewise.
* pthread_getschedparam.c: Likewise.
* pthread_setschedparam.c: Likewise.
* Versions: Likewise.
* pt-pselect.c: New file.
* Makefile (libpthread-routines): Add pt-pselect.
* Versions: Add pselect.
* tst-cancel4.c: New file.
* Makefile (tests): Add tst-cancel4.
2002-10-09 Ulrich Drepper <drepper@redhat.com>
* pthread_mutex_lock.c: Always record lock ownership.
* pthread_mutex_timedlock.c: Likewise.
* pthread_mutex_trylock.c: Likewise.
* pt-readv.c: New file.
* pt-writev.c: New file.
* pt-creat.c: New file.
* pt-msgrcv.c: New file.
* pt-msgsnd.c: New file.
* pt-poll.c: New file.
* pt-select.c: New file.
* pt-sigpause.c: New file.
* pt-sigsuspend.c: New file.
* pt-sigwait.c: New file.
* pt-sigwaitinfo.c: New file.
* pt-waitid.c: New file.
* Makefile (libpthread-routines): Add pt-readv, pt-writev, pt-creat,
pt-msgrcv, pt-msgsnd, pt-poll, pt-select, pt-sigpause, pt-sigsuspend,
pt-sigwait, pt-sigwaitinfo, and pt-waitid.
* Versions: Add all the new functions.
* tst-exit1.c: New file.
* Makefile (tests): Add tst-exit1.
* sem_timedwait.c: Minor optimization for more optimal fastpath.
2002-10-08 Ulrich Drepper <drepper@redhat.com>
* pt-fcntl.c: Only enable asynchronous cancellation for F_SETLKW.
* pthread_join.c: Enable asynchronous cancellation around lll_wait_tid
call. pthread_join is an official cancellation point.
* pthread_timedjoin.c: Likewise.
* pthread_cond_wait.c: Revert order in which internal lock are dropped
and the condvar's mutex are retrieved.
* pthread_cond_timedwait.c: Likewise.
Reported by dice@saros.East.Sun.COM.
2002-10-07 Ulrich Drepper <drepper@redhat.com>
* pthreadP.h: Cut out all type definitions and move them...
* sysdeps/unix/sysv/linux/internaltypes.h: ...here. New file.
* pthreadP.h: Include <internaltypes.h>.
* sysdeps/unix/sysv/linux/i386/lowlevelsem.h (lll_sem_post): Little
performance tweaks.
* sem_trywait.c: Shuffle #includes around to get right order.
* sem_timedwait.c: Likewise.
* sem_post.c: Likewise.
* sem_wait.c: Likewise.
* nptl 0.3 released.
* Makefile (tests): Add tst-signal3.
* tst-signal3.c: New file.
2002-10-05 Ulrich Drepper <drepper@redhat.com>
* sysdeps/unix/sysv/linux/i386/lowlevelsem.h: Tell the compiler that
the asms modify the sem object.
(__lll_sem_timedwait): Now takes struct sem* as first parameter.
* sysdeps/unix/sysv/linux/i386/bits/semaphore.h (sem_t): Don't expose
the actual members.
* pthreadP.h (struct sem): New type. Actual semaphore type.
* semaphoreP.h: Include pthreadP.h.
* sem_getvalue.c: Adjust to sem_t change.
* sem_init.c: Likewise.
* sem_open.c: Likewise.
* sem_post.c: Likewise.
* sem_timedwait.c: Likewise.
* sem_trywait.c: Likewise.
* sem_wait.c: Likewise.
2002-10-04 Ulrich Drepper <drepper@redhat.com>
* Makefile (tests): Add tst-basic2, tst-exec1, tst-exec3, tst-exec3.
* tst-basic2.c: New file.
* tst-exec1.c: New file.
* tst-exec2.c: New file.
* tst-exec3.c: New file.
* tst-fork1.c: Remove extra */.
* nptl 0.2 released. The API for IA-32 is complete.
