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[PATCH] nptl: Open libgcc.so with RTLD_NOW during pthread_cancel [BZ #22636]
- From: fweimer at redhat dot com (Florian Weimer)
- To: libc-alpha at sourceware dot org
- Date: Mon, 15 Jan 2018 16:08:42 +0100
- Subject: [PATCH] nptl: Open libgcc.so with RTLD_NOW during pthread_cancel [BZ #22636]
- Authentication-results: sourceware.org; auth=none
Disabling lazy binding reduces stack usage during unwinding.
Note that RTLD_NOW only makes a difference if libgcc.so has not
already been loaded, so this is only a partial fix.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit f993b8754080ac7572b692870e926d8b493db16c)
2018-01-10 Florian Weimer <fweimer@redhat.com>
[BZ #22636]
* sysdeps/nptl/unwind-forcedunwind.c (pthread_cancel_init): Open
libgcc.so with RTLD_NOW, to avoid lazy binding during unwind.
diff --git a/NEWS b/NEWS
index 3a719e81e3..afa170f86e 100644
--- a/NEWS
+++ b/NEWS
@@ -100,6 +100,7 @@ The following bugs are resolved with this release:
[22322] libc: [mips64] wrong bits/long-double.h installed
[22325] glibc: Memory leak in glob with GLOB_TILDE (CVE-2017-15671)
[22375] malloc returns pointer from tcache instead of NULL (CVE-2017-17426)
+ [22636] PTHREAD_STACK_MIN is too small on x86-64
[22627] $ORIGIN in $LD_LIBRARY_PATH is substituted twice
[22637] nptl: Fix stack guard size accounting
[22679] getcwd(3) can succeed without returning an absolute path
diff --git a/sysdeps/nptl/unwind-forcedunwind.c b/sysdeps/nptl/unwind-forcedunwind.c
index 33a1975f5e..ace58b2468 100644
--- a/sysdeps/nptl/unwind-forcedunwind.c
+++ b/sysdeps/nptl/unwind-forcedunwind.c
@@ -49,7 +49,7 @@ pthread_cancel_init (void)
return;
}
- handle = __libc_dlopen (LIBGCC_S_SO);
+ handle = __libc_dlopen_mode (LIBGCC_S_SO, RTLD_NOW | __RTLD_DLOPEN);
if (handle == NULL
|| (resume = __libc_dlsym (handle, "_Unwind_Resume")) == NULL