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-rw-r--r--arch/um/os-Linux/util.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/arch/um/os-Linux/util.c b/arch/um/os-Linux/util.c
index fc0f2a9de..1dca4ffbd 100644
--- a/arch/um/os-Linux/util.c
+++ b/arch/um/os-Linux/util.c
@@ -173,23 +173,38 @@ __uml_setup("quiet", quiet_cmd_param,
"quiet\n"
" Turns off information messages during boot.\n\n");
+/*
+ * The os_info/os_warn functions will be called by helper threads. These
+ * have a very limited stack size and using the libc formatting functions
+ * may overflow the stack.
+ * So pull in the kernel vscnprintf and use that instead with a fixed
+ * on-stack buffer.
+ */
+int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
+
void os_info(const char *fmt, ...)
{
+ char buf[256];
va_list list;
+ int len;
if (quiet_info)
return;
va_start(list, fmt);
- vfprintf(stderr, fmt, list);
+ len = vscnprintf(buf, sizeof(buf), fmt, list);
+ fwrite(buf, len, 1, stderr);
va_end(list);
}
void os_warn(const char *fmt, ...)
{
+ char buf[256];
va_list list;
+ int len;
va_start(list, fmt);
- vfprintf(stderr, fmt, list);
+ len = vscnprintf(buf, sizeof(buf), fmt, list);
+ fwrite(buf, len, 1, stderr);
va_end(list);
}