commit 9f349d02c6065f77b485526b3d76a637f6f079dc
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Wed Jul 24 14:05:13 2024 -0700

    linux: Update the mremap C implementation [BZ #31968]
    
    Update the mremap C implementation to support the optional argument for
    MREMAP_DONTUNMAP added in Linux 5.7 since it may not always be correct
    to implement a variadic function as a non-variadic function on all Linux
    targets.  Return MAP_FAILED and set errno to EINVAL for unknown flag bits.
    This fixes BZ #31968.
    
    Note: A test must be added when a new flag bit is introduced.
    
    Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
    (cherry picked from commit 6c40cb0e9f893d49dc7caee580a055de53562206)

diff --git a/sysdeps/unix/sysv/linux/mremap.c b/sysdeps/unix/sysv/linux/mremap.c
index 4f770799c4f2fd18..1ada5c1f40dec1f6 100644
--- a/sysdeps/unix/sysv/linux/mremap.c
+++ b/sysdeps/unix/sysv/linux/mremap.c
@@ -20,6 +20,12 @@
 #include <sysdep.h>
 #include <stdarg.h>
 #include <stddef.h>
+#include <errno.h>
+
+#define MREMAP_KNOWN_BITS \
+  (MREMAP_MAYMOVE \
+   | MREMAP_FIXED \
+   | MREMAP_DONTUNMAP)
 
 void *
 __mremap (void *addr, size_t old_len, size_t new_len, int flags, ...)
@@ -27,7 +33,13 @@ __mremap (void *addr, size_t old_len, size_t new_len, int flags, ...)
   va_list va;
   void *new_addr = NULL;
 
-  if (flags & MREMAP_FIXED)
+  if (flags & ~(MREMAP_KNOWN_BITS))
+    {
+      __set_errno (EINVAL);
+      return MAP_FAILED;
+    }
+
+  if (flags & (MREMAP_FIXED | MREMAP_DONTUNMAP))
     {
       va_start (va, flags);
       new_addr = va_arg (va, void *);