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| author | kib <kib@FreeBSD.org> | 2016-02-08 19:24:13 +0000 |
|---|---|---|
| committer | kib <kib@FreeBSD.org> | 2016-02-08 19:24:13 +0000 |
| commit | 42e09be9c23e730d42b331384d128dbba8719c04 (patch) | |
| tree | c91cbb77944f06638bce887f736eaeafed34a388 /lib/libc/sys | |
| parent | 42bcd86bfbff24f6d52e96805b6d8d535c7db051 (diff) | |
| download | FreeBSD-src-42e09be9c23e730d42b331384d128dbba8719c04.zip FreeBSD-src-42e09be9c23e730d42b331384d128dbba8719c04.tar.gz | |
If libthr.so is dlopened without RTLD_GLOBAL flag, the libthr symbols
do not participate in the global symbols namespace, but rtld locks are
still replaced and functions are interposed. In particular,
__pthread_map_stacks_exec is resolved to the libc version. If a
library is loaded later, which requires adjustment of the stack
protection mode, rtld calls into libc __pthread_map_stacks_exec due to
the symbols scope. The libc version might recurse into binder and
recursively acquire rtld bind lock, causing the hang.
Make libc __pthread_map_stacks_exec() interposed, which synchronizes
rtld locks and version of the stack exec hook when libthr loaded,
regardless of the symbol scope control or symbol resolution order.
The __pthread_map_stacks_exec() symbol is removed from the private
version in libthr since libc symbol now operates correctly in presence
of libthr.
Reported and tested by: markj
Sponsored by: The FreeBSD Foundation
MFC after: 2 weeks
Diffstat (limited to 'lib/libc/sys')
| -rw-r--r-- | lib/libc/sys/interposing_table.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/lib/libc/sys/interposing_table.c b/lib/libc/sys/interposing_table.c index 08dfbb1..75bb280 100644 --- a/lib/libc/sys/interposing_table.c +++ b/lib/libc/sys/interposing_table.c @@ -78,6 +78,7 @@ interpos_func_t __libc_interposing[INTERPOS_MAX] = { SLOT(kevent, __sys_kevent), SLOT(wait6, __sys_wait6), SLOT(ppoll, __sys_ppoll), + SLOT(map_stacks_exec, __libc_map_stacks_exec), }; #undef SLOT |
