This simple testcase: locale_t st = newlocale(LC_ALL_MASK, "C", (locale_t)0); locale_t st2 = newlocale(LC_CTYPE_MASK, "en_US.UTF-8", st); is sufficient to reproduce a crash in _newlocale_r. After the first call to newlocale, `st' points to __C_locale, which is const. When using `st' as locale base in the second call, _newlocale_r tries to set pointers inside base to NULL. This is bad if base is __C_locale, obviously. Add a test to avoid trying to overwrite pointer values inside base if base is __C_locale. Signed-off-by: Corinna Vinschen <corinna@vinschen.de> --- newlib/libc/locale/newlocale.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/newlib/libc/locale/newlocale.c b/newlib/libc/locale/newlocale.c index 0789d5fd95ec..08f29dbcc0c1 100644 --- a/newlib/libc/locale/newlocale.c +++ b/newlib/libc/locale/newlocale.c @@ -188,7 +188,8 @@ _newlocale_r (struct _reent *p, int category_mask, const char *locale, if (tmp_locale.lc_cat[i].buf == (const void *) -1) { tmp_locale.lc_cat[i].buf = base->lc_cat[i].buf; - base->lc_cat[i].ptr = base->lc_cat[i].buf = NULL; + if (base != __get_C_locale ()) + base->lc_cat[i].ptr = base->lc_cat[i].buf = NULL; } #endif /* __HAVE_LOCALE_INFO__ */ _freelocale_r (p, base); -- 2.37.1