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adbd3ba137
Remove the odd atomic_forced_read which is neither atomic nor forced. Some uses are completely redundant, so simply remove them. In other cases the intended use is to force a memory ordering, so use acquire load for those. In yet other cases their purpose is unclear, for example __nscd_cache_search appears to allow concurrent accesses to the cache while it is being garbage collected by another thread! Use relaxed atomic loads here to block spills from accidentally reloading memory that is being changed. Passes regress on AArch64, OK for commit?
71 lines
2.3 KiB
C
71 lines
2.3 KiB
C
/* Copyright (C) 2009-2025 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <errno.h>
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#include <signal.h>
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#include <string.h>
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#include <unistd.h>
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#include <pthreadP.h>
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#include <tls.h>
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#include <sysdep.h>
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#include <shlib-compat.h>
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int
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__pthread_sigqueue (pthread_t threadid, int signo, const union sigval value)
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{
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#ifdef __NR_rt_tgsigqueueinfo
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struct pthread *pd = (struct pthread *) threadid;
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/* Force load of pd->tid into local variable or register. Otherwise
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if a thread exits between ESRCH test and tgkill, we might return
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EINVAL, because pd->tid would be cleared by the kernel. */
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pid_t tid = atomic_load_relaxed (&pd->tid);
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if (__glibc_unlikely (tid <= 0))
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/* Not a valid thread handle. */
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return ESRCH;
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/* Disallow sending the signal we use for cancellation, timers,
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for the setxid implementation. */
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if (signo == SIGCANCEL || signo == SIGTIMER || signo == SIGSETXID)
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return EINVAL;
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pid_t pid = getpid ();
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/* Set up the siginfo_t structure. */
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siginfo_t info;
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memset (&info, '\0', sizeof (siginfo_t));
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info.si_signo = signo;
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info.si_code = SI_QUEUE;
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info.si_pid = pid;
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info.si_uid = __getuid ();
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info.si_value = value;
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/* We have a special syscall to do the work. */
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int val = INTERNAL_SYSCALL_CALL (rt_tgsigqueueinfo, pid, tid, signo,
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&info);
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return (INTERNAL_SYSCALL_ERROR_P (val)
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? INTERNAL_SYSCALL_ERRNO (val) : 0);
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#else
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return ENOSYS;
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#endif
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}
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versioned_symbol (libc, __pthread_sigqueue, pthread_sigqueue, GLIBC_2_34);
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#if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_11, GLIBC_2_34)
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compat_symbol (libpthread, __pthread_sigqueue, pthread_sigqueue, GLIBC_2_11);
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#endif
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