After commit f1ac745583 ("arm: Use "nr"
constraint for Systemtap probes [BZ #24164]"), we load pd->result into
a register in the probe below:
/* Free the TCB. */
__free_tcb (pd);
}
else
pd->joinid = NULL;
LIBC_PROBE (pthread_join_ret, 3, threadid, result, pd->result);
However, at this point, the thread descriptor has been freed. If the
thread stack does not fit into the thread stack cache, the memory will
have been unmapped, and the program will crash in the probe.
Patch ce7eb0e903 ("nptl: Cleanup cancellation macros") changed the
join sequence for internal common __pthread_timedjoin_ex to use the
new macro lll_wait_tid. The idea was this macro would issue the
cancellable futex operation depending whether the timeout is used or
not. However if a timeout is used, __lll_timedwait_tid is called and
it is not a cancellable entrypoint.
This patch fixes it by simplifying the code in various ways:
- Instead of adding the cancellation handling on __lll_timedwait_tid,
it moves the generic implementation to pthread_join_common.c (called
now timedwait_tid with some fixes to use the correct type for pid).
- The llvm_wait_tid macro is removed, along with its replication on
x86_64, i686, and sparc arch-specific lowlevellock.h.
- sparc32 __lll_timedwait_tid is also removed, since the code is similar
to generic one.
- x86_64 and i386 provides arch-specific __lll_timedwait_tid which is
also removed since they are similar in functionality to generic C code
and there is no indication it is better than compiler generated code.
New tests, tst-join8 and tst-join9, are provided to check if
pthread_timedjoin_np acts as a cancellation point.
Checked on x86_64-linux-gnu, i686-linux-gnu, sparcv9-linux-gnu, and
aarch64-linux-gnu.
[BZ #24215]
* nptl/Makefile (lpthread-routines): Remove lll_timedwait_tid.
(tests): Add tst-join8 tst-join9.
* nptl/lll_timedwait_tid.c: Remove file.
* sysdeps/sparc/sparc32/lll_timedwait_tid.c: Likewise.
* sysdeps/unix/sysv/linux/i386/lll_timedwait_tid.c: Likewise.
* sysdeps/sysv/linux/x86_64/lll_timedwait_tid.c: Likewise.
* nptl/pthread_join_common.c (timedwait_tid): New function.
(__pthread_timedjoin_ex): Act as cancellation entrypoint is block
is set.
* nptl/tst-join5.c (thread_join): New function.
(tf1, tf2, do_test): Use libsupport and add pthread_timedjoin_np
check.
* nptl/tst-join8.c: New file.
* nptl/tst-join9.c: Likewise.
* sysdeps/nptl/lowlevellock-futex.h (lll_futex_wait_cancel,
lll_futex_timed_wait_cancel): Add generic macros.
* sysdeps/nptl/lowlevellock.h (__lll_timedwait_tid, lll_wait_tid):
Remove definitions.
* sysdeps/unix/sysv/linux/i386/lowlevellock.h: Likewise.
* sysdeps/unix/sysv/linux/sparc/lowlevellock.h: Likewise.
* sysdeps/unix/sysv/linux/x86_64/lowlevellock.h: Likewise.
* sysdeps/sparc/sparc32/lowlevellock.c (__lll_timedwait_tid):
Remove function.
* sysdeps/unix/sysv/linux/i386/lowlevellock.S (__lll_timedwait_tid):
Likewise.
* sysdeps/unix/sysv/linux/x86_64/lowlevellock.S: Likewise.
* sysdeps/unix/sysv/linux/lowlevellock-futex.h
(lll_futex_timed_wait_cancel): New macro.
This patch wraps all uses of *_{enable,disable}_asynccancel and
and *_CANCEL_{ASYNC,RESET} in either already provided macros
(lll_futex_timed_wait_cancel) or creates new ones if the
functionality is not provided (SYSCALL_CANCEL_NCS, lll_futex_wait_cancel,
and lll_futex_timed_wait_cancel).
Also for some generic implementations, the direct call of the macros
are removed since the underlying symbols are suppose to provide
cancellation support.
This is a priliminary patch intended to simplify the work required
for BZ#12683 fix. It is a refactor change, no semantic changes are
expected.
Checked on x86_64-linux-gnu and i686-linux-gnu.
* nptl/pthread_join_common.c (__pthread_timedjoin_ex): Use
lll_wait_tid with timeout.
* nptl/sem_wait.c (__old_sem_wait): Use lll_futex_wait_cancel.
* sysdeps/nptl/aio_misc.h (AIO_MISC_WAIT): Use
futex_reltimed_wait_cancelable for cancelabla mode.
* sysdeps/nptl/gai_misc.h (GAI_MISC_WAIT): Likewise.
* sysdeps/posix/open64.c (__libc_open64): Do not call cancelation
macros.
* sysdeps/posix/sigwait.c (__sigwait): Likewise.
* sysdeps/posix/waitid.c (__sigwait): Likewise.
* sysdeps/unix/sysdep.h (__SYSCALL_CANCEL_CALL,
SYSCALL_CANCEL_NCS): New macro.
* sysdeps/nptl/lowlevellock.h (lll_wait_tid): Add timeout argument.
(lll_timedwait_tid): Remove macro.
* sysdeps/unix/sysv/linux/i386/lowlevellock.h (lll_wait_tid):
Likewise.
(lll_timedwait_tid): Likewise.
* sysdeps/unix/sysv/linux/sparc/lowlevellock.h (lll_wait_tid):
Likewise.
(lll_timedwait_tid): Likewise.
* sysdeps/unix/sysv/linux/x86_64/lowlevellock.h (lll_wait_tid):
Likewise.
(lll_timedwait_tid): Likewise.
* sysdeps/unix/sysv/linux/clock_nanosleep.c (__clock_nanosleep):
Use INTERNAL_SYSCALL_CANCEL.
* sysdeps/unix/sysv/linux/futex-internal.h
(futex_reltimed_wait_cancelable): Use LIBC_CANCEL_{ASYNC,RESET}
instead of __pthread_{enable,disable}_asynccancel.
* sysdeps/unix/sysv/linux/lowlevellock-futex.h
(lll_futex_wait_cancel): New macro.
This patch consolidates the pthread_join and gnu extensions to avoid
code duplication. The function pthread_join, pthread_tryjoin_np, and
pthread_timedjoin_np are now based on pthread_timedjoin_ex.
It also fixes some inconsistencies on ESRCH, EINVAL, EDEADLK handling
(where each implementation differs from each other) and also on
clenup handler (which now always use a CAS).
Checked on i686-linux-gnu and x86_64-linux-gnu.
* nptl/pthreadP.h (__pthread_timedjoin_np): Define.
* nptl/pthread_join.c (pthread_join): Use __pthread_timedjoin_np.
* nptl/pthread_tryjoin.c (pthread_tryjoin): Likewise.
* nptl/pthread_timedjoin.c (cleanup): Use CAS on argument setting.
(pthread_timedjoin_np): Define internal symbol and common code from
pthread_join.
* sysdeps/unix/sysv/linux/i386/lowlevellock.h (__lll_timedwait_tid):
Remove superflous checks.
* sysdeps/unix/sysv/linux/x86_64/lowlevellock.h (__lll_timedwait_tid):
Likewise.
Signed-off-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
