1 files changed, 4 insertions, 1 deletions
diff --git a/src/coredump/stacktrace.c b/src/coredump/stacktrace.c
index d37ffae020..95fd27b79a 100644
--- a/src/coredump/stacktrace.c
+++ b/src/coredump/stacktrace.c
@@ -20,6 +20,7 @@
 
 #include <dwarf.h>
 #include <elfutils/libdwfl.h>
+#include <stdio_ext.h>
 
 #include "alloc-util.h"
 #include "fd-util.h"
@@ -108,7 +109,7 @@ static int thread_callback(Dwfl_Thread *thread, void *userdata) {
                 return DWARF_CB_ABORT;
 
         if (c->n_thread != 0)
-                fputc_unlocked('\n', c->f);
+                fputc('\n', c->f);
 
         c->n_frame = 0;
 
@@ -145,6 +146,8 @@ int coredump_make_stack_trace(int fd, const char *executable, char **ret) {
         if (!c.f)
                 return -ENOMEM;
 
+        (void) __fsetlocking(c.f, FSETLOCKING_BYCALLER);
+
         elf_version(EV_CURRENT);
 
         c.elf = elf_begin(fd, ELF_C_READ_MMAP, NULL);