Index: sys/i386/i386/identcpu.c
===================================================================
--- sys/i386/i386/identcpu.c	(revision 198853)
+++ sys/i386/i386/identcpu.c	(working copy)
@@ -1303,6 +1303,24 @@ print_AMD_info(void)
 			    (amd_whcr & 0x0100) ? "Enable" : "Disable");
 		}
 	}
+
+	/*
+	 * Opteron Rev E shows a bug as in very rare occasions a read memory
+	 * barrier is not performed as expected if it is followed by a
+	 * non-atomic read-modify-write instruction.
+	 * As long as that bug pops up very rarely (intensive machine usages
+	 * on other operating systems generally report one unexplainable
+	 * crash any 2 months) and as long as a model specific fix would be
+	 * inpratical at this stage, print out a warning string if the broken
+	 * model and family are identified.
+	 */
+	if (CPUID_TO_FAMILY(cpu_id) == 0xf && CPUID_TO_MODEL(cpu_id) >= 0x20 &&
+	    CPUID_TO_MODEL(cpu_id) <= 0x3f) {
+		printf("WARNING: This architecture revision has known SMP "
+		    "hardware bugs which may cause random instability\n);
+		printf("WARNING: For details see: "
+		    "http://bugzilla.kernel.org/show_bug.cgi?id=11305\n");
+	}
 }
 
 static void
Index: sys/amd64/amd64/identcpu.c
===================================================================
--- sys/amd64/amd64/identcpu.c	(revision 198853)
+++ sys/amd64/amd64/identcpu.c	(working copy)
@@ -607,6 +607,24 @@ print_AMD_info(void)
 		printf(", %d lines/tag", (regs[2] >> 8) & 0x0f);
 		print_AMD_l2_assoc((regs[2] >> 12) & 0x0f);	
 	}
+
+	/*
+	 * Opteron Rev E shows a bug as in very rare occasions a read memory 
+	 * barrier is not performed as expected if it is followed by a 
+	 * non-atomic read-modify-write instruction.  
+	 * As long as that bug pops up very rarely (intensive machine usages
+	 * on other operating systems generally report one unexplainable 
+	 * crash any 2 months) and as long as a model specific fix would be
+	 * inpratical at this stage, print out a warning string if the broken
+	 * model and family are identified.
+	 */
+	if (CPUID_TO_FAMILY(cpu_id) == 0xf && CPUID_TO_MODEL(cpu_id) >= 0x20 &&
+	    CPUID_TO_MODEL(cpu_id) <= 0x3f) {
+		printf("WARNING: This architecture revision has known SMP "
+		    "hardware bugs which may cause random instability\n);
+		printf("WARNING: For details see: "
+		    "http://bugzilla.kernel.org/show_bug.cgi?id=11305\n");
+	}
 }
 
 static void