diff --git a/security/sandbox/linux/SandboxFilter.cpp b/security/sandbox/linux/SandboxFilter.cpp
--- a/security/sandbox/linux/SandboxFilter.cpp
+++ b/security/sandbox/linux/SandboxFilter.cpp
@@ -1048,16 +1048,24 @@ public:
 
     case __NR_mprotect:
     case __NR_brk:
     case __NR_madvise:
       // libc's realloc uses mremap (Bug 1286119); wasm does too (bug 1342385).
     case __NR_mremap:
       return Allow();
 
+      // Bug 1462640: Mesa libEGL uses mincore to test whether values
+      // are pointers, for reasons.
+    case __NR_mincore: {
+      Arg<size_t> length(1);
+      return If(length == getpagesize(), Allow())
+             .Else(SandboxPolicyCommon::EvaluateSyscall(sysno));
+    }
+
     case __NR_sigaltstack:
       return Allow();
 
 #ifdef __NR_set_thread_area
     case __NR_set_thread_area:
       return Allow();
 #endif