https://bugs.gentoo.org/949654
https://bugreports.qt.io/browse/QTBUG-134631
--- a/src/3rdparty/chromium/sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.cc
+++ b/src/3rdparty/chromium/sandbox/linux/seccomp-bpf-helpers/syscall_parameters_restrictions.cc
@@ -36,4 +36,8 @@
 #include "sandbox/linux/system_headers/linux_time.h"
 
+#if !defined(MAP_DROPPABLE)
+#define MAP_DROPPABLE	0x08    // Zero memory under memory pressure.
+#endif
+
 #if (BUILDFLAG(IS_LINUX) || BUILDFLAG(IS_CHROMEOS_LACROS)) && \
     !defined(__arm__) && !defined(__aarch64__) &&             \
@@ -239,5 +243,5 @@
   const uint64_t kAllowedMask = MAP_SHARED | MAP_PRIVATE | MAP_ANONYMOUS |
                                 MAP_STACK | MAP_NORESERVE | MAP_FIXED |
-                                MAP_DENYWRITE | MAP_LOCKED |
+                                MAP_DENYWRITE | MAP_LOCKED | MAP_DROPPABLE |
                                 kArchSpecificAllowedMask;
   const Arg<int> flags(3);
