CVS commit: src/libexec/ld.elf_so

["Taylor R Campbell" <riastradh%netbsd.org@localhost>]

Module Name:    src
Committed By:   riastradh
Date:           Tue Sep 13 10:18:58 UTC 2022

Modified Files:
        src/libexec/ld.elf_so: rtld.c

Log Message:
ld.elf_so(8): Make fork take a shared, not exclusive, lock.

We only need to ensure that there are no concurrent modifications to
the rtld data structures in flight, since the threads that began
those modifications will not exist in the child and will therefore be
unable to complete them in the child.

A shared lock suffices to ensure there are no such concurrent
modifications in flight; an exclusive lock is not necessary, and can
cause deadlock if fork is executed from a signal handler, which is
explicitly allowed by POSIX (and our own sigaction(2) man page) which
marks fork as async-signal-safe.

PR lib/56979


To generate a diff of this commit:
cvs rdiff -u -r1.211 -r1.212 src/libexec/ld.elf_so/rtld.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.