diff --git a/src/util-debug.c b/src/util-debug.c
index 97b1626b2b..d4ddc14a2d 100644
--- a/src/util-debug.c
+++ b/src/util-debug.c
@@ -577,11 +577,13 @@ SCError SCLogMessage(const SCLogLevel log_level, const char *file,
                                           log_level, file, line, function,
                                           error_code, message) == 0)
                 {
+                    SCMutexLock(&op_iface_ctx->fp_mutex);
                     if (op_iface_ctx->rotation_flag) {
                         SCLogReopen(op_iface_ctx);
                         op_iface_ctx->rotation_flag = 0;
                     }
                     SCLogPrintToStream(op_iface_ctx->file_d, buffer);
+                    SCMutexUnlock(&op_iface_ctx->fp_mutex);
                 }
                 break;
             case SC_LOG_OP_IFACE_SYSLOG:
@@ -714,6 +716,7 @@ static inline SCLogOPIfaceCtx *SCLogInitFileOPIface(const char *file,
         goto error;
     }
 
+    SCMutexInit(&iface_ctx->fp_mutex, NULL);
     OutputRegisterFileRotationFlag(&iface_ctx->rotation_flag);
 
     iface_ctx->log_level = log_level;
diff --git a/src/util-debug.h b/src/util-debug.h
index 5148fe19f6..8cf49beda3 100644
--- a/src/util-debug.h
+++ b/src/util-debug.h
@@ -139,6 +139,9 @@ typedef struct SCLogOPIfaceCtx_ {
     /* override for the global_log_format(currently not used) */
     const char *log_format;
 
+    /* Mutex used for locking around rotate/write to a file. */
+    SCMutex fp_mutex;
+
     struct SCLogOPIfaceCtx_ *next;
 } SCLogOPIfaceCtx;