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a687683b99
Rtld locks from libthr defer signals delivery, which means that binding is not possible while a signal handler is executed. Binding might upgrade read-locked rtld_bind_lock to write-lock, if symbol resolution requires loading filters. If a signal would be delivered while rtld is in read-locked section, and signal handler needs binding which upgrades the lock, for non-threaded image that uses default rtld locks, we get the rtld data structures modified under the top-level active rtld frame. To correct the problem, mask signals for read-locking of default locks in addition to the write-locking. It is very cheap now with sigfastblock(2). Note that the global state is used to track pre-locked state of either sigfastblock(2) or signal mask (if sigfastblock(2) is administratively disabled). It is fine for non-threaded images since there are no other threads. But I believe that it is fine for threaded images using libc_r as well, since masking signals disables preemption (I did not tested it). NetBSD PR: https://gnats.netbsd.org/56979 Reported by: tmunro Reviewed by: markj Sponsored by: The FreeBSD Foundation MFC after: 2 weeks Differential revision: https://reviews.freebsd.org/D36396 |
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| aarch64 | ||
| amd64 | ||
| arm | ||
| i386 | ||
| powerpc | ||
| powerpc64 | ||
| riscv | ||
| rtld-libc | ||
| tests | ||
| debug.c | ||
| debug.h | ||
| libmap.c | ||
| libmap.conf | ||
| libmap.h | ||
| Makefile | ||
| Makefile.depend | ||
| map_object.c | ||
| rtld_lock.c | ||
| rtld_lock.h | ||
| rtld_malloc.c | ||
| rtld_malloc.h | ||
| rtld_paths.h | ||
| rtld_printf.c | ||
| rtld_printf.h | ||
| rtld_tls.h | ||
| rtld_utrace.h | ||
| rtld.1 | ||
| rtld.c | ||
| rtld.h | ||
| Symbol.map | ||
| xmalloc.c | ||