diff --git a/components/fatfs/src/vfs_fat_sdmmc.c b/components/fatfs/src/vfs_fat_sdmmc.c
index 68751cb50..5e79d4a9f 100644
--- a/components/fatfs/src/vfs_fat_sdmmc.c
+++ b/components/fatfs/src/vfs_fat_sdmmc.c
@@ -128,6 +128,7 @@ esp_err_t esp_vfs_fat_sdmmc_mount(const char* base_path,
             goto fail;
         }
         free(workbuf);
+        workbuf = NULL;
         ESP_LOGW(TAG, "mounting again");
         res = f_mount(fs, drv, 0);
         if (res != FR_OK) {