fix potential deadlock in dlerror buffer handling at thread exit

[musl] / src / stdio / vfprintf.c

diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c
index 5e7be71..9b961e7 100644 (file)
--- a/src/stdio/vfprintf.c
+++ b/src/stdio/vfprintf.c
@@ -5,6 +5,7 @@
 #include <string.h>
 #include <stdarg.h>
 #include <stddef.h>
+#include <stdlib.h>
 #include <wchar.h>
 #include <inttypes.h>
 #include <math.h>
@@ -674,11 +675,12 @@ int vfprintf(FILE *restrict f, const char *restrict fmt, va_list ap)
        if (f->mode < 1) f->flags &= ~F_ERR;
        if (!f->buf_size) {
                saved_buf = f->buf;
-               f->wpos = f->wbase = f->buf = internal_buf;
+               f->buf = internal_buf;
                f->buf_size = sizeof internal_buf;
-               f->wend = internal_buf + sizeof internal_buf;
+               f->wpos = f->wbase = f->wend = 0;
        }
-       ret = printf_core(f, fmt, &ap2, nl_arg, nl_type);
+       if (!f->wend && __towrite(f)) ret = -1;
+       else ret = printf_core(f, fmt, &ap2, nl_arg, nl_type);
        if (saved_buf) {
                f->write(f, 0, 0);
                if (!f->wpos) ret = -1;