Fix a potential memory leak bug in write_boot_rom() (v6.2.0).

[wliang]

Hi all,

I find a memory leak bug in QEMU 6.2.0, which is in 
write_boot_rom()(./hw/arm/aspeed.c).

Specifically, at line 276, a memory chunk is allocated with g_new0() and 
assigned to the variable 'storage'. However, if the branch takes true at line 
277, there will be only an error report at line 278 but not a free operation 
for 'storage' before function returns. As a result, a memory leak bug is 
triggered.


259    BlockBackend *blk = blk_by_legacy_dinfo(dinfo);
...
276    storage = g_new0(uint8_t, rom_size);
277    if (blk_pread(blk, 0, storage, rom_size) < 0) {
278        error_setg(errp, "failed to read the initial flash content");
279        return;
280    }


I believe that the problem can be fixed by adding a g_free() before the 
function returns.


277    if (blk_pread(blk, 0, storage, rom_size) < 0) {
278        error_setg(errp, "failed to read the initial flash content");
+++    g_free(storage);
279        return;
280    }


I'm looking forward to your confirmation.

Best,
Wentao

--- ./hw/arm/aspeed.c	2022-02-23 15:06:31.928708083 +0800
+++ ./hw/arm/aspeed-PATCH.c	2022-02-23 21:22:28.200802801 +0800
@@ -276,6 +276,7 @@
     storage = g_new0(uint8_t, rom_size);
     if (blk_pread(blk, 0, storage, rom_size) < 0) {
         error_setg(errp, "failed to read the initial flash content");
+        g_free(storage);
         return;
     }